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author | d34d <clark@cyngn.com> | 2014-08-24 09:30:38 -0700 |
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committer | Clark Scheff <clark@cyngn.com> | 2014-08-25 16:45:24 +0000 |
commit | 1c8f369803ff0f93c29e8f1e682a33e9b861da26 (patch) | |
tree | 108e9fc84a73ee029383cd3ed937439a713715d7 /src/au/com/glassechidna | |
parent | c4fe984717aa93eaa2b3dc09066539208dfda03e (diff) | |
download | packages_apps_ThemeChooser-1c8f369803ff0f93c29e8f1e682a33e9b861da26.zip packages_apps_ThemeChooser-1c8f369803ff0f93c29e8f1e682a33e9b861da26.tar.gz packages_apps_ThemeChooser-1c8f369803ff0f93c29e8f1e682a33e9b861da26.tar.bz2 |
Use VelocityViewPager in component selector
Change-Id: I8f6774e593a8a67d5de90dbec6b9a040d9f95052
Diffstat (limited to 'src/au/com/glassechidna')
-rw-r--r-- | src/au/com/glassechidna/velocityviewpager/VelocityScroller.java | 1011 | ||||
-rw-r--r-- | src/au/com/glassechidna/velocityviewpager/VelocityViewPager.java | 3101 |
2 files changed, 4112 insertions, 0 deletions
diff --git a/src/au/com/glassechidna/velocityviewpager/VelocityScroller.java b/src/au/com/glassechidna/velocityviewpager/VelocityScroller.java new file mode 100644 index 0000000..d1946e4 --- /dev/null +++ b/src/au/com/glassechidna/velocityviewpager/VelocityScroller.java @@ -0,0 +1,1011 @@ +/* + * Copyright (C) 2010 The Android Open Source Project + * Copyright (C) 2014 Benjamin Dobell, Glass Echidna + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package au.com.glassechidna.velocityviewpager; + +import android.content.Context; +import android.hardware.SensorManager; +import android.util.FloatMath; +import android.util.Log; +import android.view.ViewConfiguration; +import android.view.animation.AnimationUtils; +import android.view.animation.Interpolator; + +/** + * Based on Google's OverScroller, this class encapsulates scrolling with the + * ability to overshoot the bounds of a scrolling operation. This class is a + * drop-in replacement for {@link android.widget.Scroller} in most cases. + * + * Relative to Google's OverScroller, this class contains only minor changes + * that add support for "under scrolling" behaviour. Additionally, the viscous + * fluid behaviour is taken from Google's Scroller class and included here + * because it is not publicly accessible through the Android SDK. + */ +public class VelocityScroller { + private int mMode; + + private final SplineOverScroller mScrollerX; + private final SplineOverScroller mScrollerY; + + private Interpolator mInterpolator; + + private final boolean mFlywheel; + + private static final int DEFAULT_DURATION = 250; + private static final int SCROLL_MODE = 0; + private static final int FLING_MODE = 1; + + private static float sViscousFluidScale; + private static float sViscousFluidNormalize; + + private static float viscousFluid(float x) + { + x *= sViscousFluidScale; + if (x < 1.0f) { + x -= (1.0f - (float) Math.exp(-x)); + } else { + float start = 0.36787944117f; // 1/e == exp(-1) + x = 1.0f - (float) Math.exp(1.0f - x); + x = start + x * (1.0f - start); + } + x *= sViscousFluidNormalize; + return x; + } + + /** + * Creates an VelocityScroller with a viscous fluid scroll interpolator and flywheel. + * @param context + */ + public VelocityScroller(Context context) { + this(context, null); + } + + /** + * Creates an VelocityScroller with flywheel enabled. + * @param context The context of this application. + * @param interpolator The scroll interpolator. If null, a default (viscous) interpolator will + * be used. + */ + public VelocityScroller(Context context, Interpolator interpolator) { + this(context, interpolator, true); + } + + /** + * Creates an VelocityScroller. + * @param context The context of this application. + * @param interpolator The scroll interpolator. If null, a default (viscous) interpolator will + * be used. + * @param flywheel If true, successive fling motions will keep on increasing scroll speed. + * @hide + */ + public VelocityScroller(Context context, Interpolator interpolator, boolean flywheel) { + mInterpolator = interpolator; + mFlywheel = flywheel; + mScrollerX = new SplineOverScroller(context); + mScrollerY = new SplineOverScroller(context); + } + + /** + * Creates an VelocityScroller with flywheel enabled. + * @param context The context of this application. + * @param interpolator The scroll interpolator. If null, a default (viscous) interpolator will + * be used. + * @param bounceCoefficientX A value between 0 and 1 that will determine the proportion of the + * velocity which is preserved in the bounce when the horizontal edge is reached. A null value + * means no bounce. This behavior is no longer supported and this coefficient has no effect. + * @param bounceCoefficientY Same as bounceCoefficientX but for the vertical direction. This + * behavior is no longer supported and this coefficient has no effect. + * !deprecated Use {!link #VelocityScroller(Context, Interpolator, boolean)} instead. + */ + public VelocityScroller(Context context, Interpolator interpolator, + float bounceCoefficientX, float bounceCoefficientY) { + this(context, interpolator, true); + } + + /** + * Creates an VelocityScroller. + * @param context The context of this application. + * @param interpolator The scroll interpolator. If null, a default (viscous) interpolator will + * be used. + * @param bounceCoefficientX A value between 0 and 1 that will determine the proportion of the + * velocity which is preserved in the bounce when the horizontal edge is reached. A null value + * means no bounce. This behavior is no longer supported and this coefficient has no effect. + * @param bounceCoefficientY Same as bounceCoefficientX but for the vertical direction. This + * behavior is no longer supported and this coefficient has no effect. + * @param flywheel If true, successive fling motions will keep on increasing scroll speed. + * !deprecated Use {!link VelocityScroller(Context, Interpolator, boolean)} instead. + */ + public VelocityScroller(Context context, Interpolator interpolator, + float bounceCoefficientX, float bounceCoefficientY, boolean flywheel) { + this(context, interpolator, flywheel); + } + + void setInterpolator(Interpolator interpolator) { + mInterpolator = interpolator; + } + + /** + * The amount of friction applied to flings. The default value + * is {@link android.view.ViewConfiguration#getScrollFriction}. + * + * @param friction A scalar dimension-less value representing the coefficient of + * friction. + */ + public final void setFriction(float friction) { + mScrollerX.setFriction(friction); + mScrollerY.setFriction(friction); + } + + /** + * + * Returns whether the scroller has finished scrolling. + * + * @return True if the scroller has finished scrolling, false otherwise. + */ + public final boolean isFinished() { + return mScrollerX.mFinished && mScrollerY.mFinished; + } + + /** + * Force the finished field to a particular value. Contrary to + * {@link #abortAnimation()}, forcing the animation to finished + * does NOT cause the scroller to move to the final x and y + * position. + * + * @param finished The new finished value. + */ + public final void forceFinished(boolean finished) { + mScrollerX.mFinished = mScrollerY.mFinished = finished; + } + + /** + * Returns the current X offset in the scroll. + * + * @return The new X offset as an absolute distance from the origin. + */ + public final int getCurrX() { + return mScrollerX.mCurrentPosition; + } + + /** + * Returns the current Y offset in the scroll. + * + * @return The new Y offset as an absolute distance from the origin. + */ + public final int getCurrY() { + return mScrollerY.mCurrentPosition; + } + + /** + * Returns the absolute value of the current velocity. + * + * @return The original velocity less the deceleration, norm of the X and Y velocity vector. + */ + public float getCurrVelocity() { + float squaredNorm = mScrollerX.mCurrVelocity * mScrollerX.mCurrVelocity; + squaredNorm += mScrollerY.mCurrVelocity * mScrollerY.mCurrVelocity; + return FloatMath.sqrt(squaredNorm); + } + + /** + * Returns the start X offset in the scroll. + * + * @return The start X offset as an absolute distance from the origin. + */ + public final int getStartX() { + return mScrollerX.mStart; + } + + /** + * Returns the start Y offset in the scroll. + * + * @return The start Y offset as an absolute distance from the origin. + */ + public final int getStartY() { + return mScrollerY.mStart; + } + + /** + * Returns where the scroll will end. Valid only for "fling" scrolls. + * + * @return The final X offset as an absolute distance from the origin. + */ + public final int getFinalX() { + return mScrollerX.mFinal; + } + + /** + * Returns where the scroll will end. Valid only for "fling" scrolls. + * + * @return The final Y offset as an absolute distance from the origin. + */ + public final int getFinalY() { + return mScrollerY.mFinal; + } + + /** + * Returns how long the scroll event will take, in milliseconds. + * + * @return The duration of the scroll in milliseconds. + * + * @hide Pending removal once nothing depends on it + * @deprecated VelocityScroller don't necessarily have a fixed duration. + * This function will lie to the best of its ability. + */ + @Deprecated + public final int getDuration() { + return Math.max(mScrollerX.mDuration, mScrollerY.mDuration); + } + + /** + * Extend the scroll animation. This allows a running animation to scroll + * further and longer, when used with {@link #setFinalX(int)} or {@link #setFinalY(int)}. + * + * @param extend Additional time to scroll in milliseconds. + * @see #setFinalX(int) + * @see #setFinalY(int) + * + * @hide Pending removal once nothing depends on it + * @deprecated VelocityScroller don't necessarily have a fixed duration. + * Instead of setting a new final position and extending + * the duration of an existing scroll, use startScroll + * to begin a new animation. + */ + @Deprecated + public void extendDuration(int extend) { + mScrollerX.extendDuration(extend); + mScrollerY.extendDuration(extend); + } + + /** + * Sets the final position (X) for this scroller. + * + * @param newX The new X offset as an absolute distance from the origin. + * @see #extendDuration(int) + * @see #setFinalY(int) + * + * @hide Pending removal once nothing depends on it + * @deprecated VelocityScroller's final position may change during an animation. + * Instead of setting a new final position and extending + * the duration of an existing scroll, use startScroll + * to begin a new animation. + */ + @Deprecated + public void setFinalX(int newX) { + mScrollerX.setFinalPosition(newX); + } + + /** + * Sets the final position (Y) for this scroller. + * + * @param newY The new Y offset as an absolute distance from the origin. + * @see #extendDuration(int) + * @see #setFinalX(int) + * + * @hide Pending removal once nothing depends on it + * @deprecated VelocityScroller's final position may change during an animation. + * Instead of setting a new final position and extending + * the duration of an existing scroll, use startScroll + * to begin a new animation. + */ + @Deprecated + public void setFinalY(int newY) { + mScrollerY.setFinalPosition(newY); + } + + /** + * Call this when you want to know the new location. If it returns true, the + * animation is not yet finished. + */ + public boolean computeScrollOffset() { + if (isFinished()) { + return false; + } + + switch (mMode) { + case SCROLL_MODE: + long time = AnimationUtils.currentAnimationTimeMillis(); + // Any scroller can be used for time, since they were started + // together in scroll mode. We use X here. + final long elapsedTime = time - mScrollerX.mStartTime; + + final int duration = mScrollerX.mDuration; + if (elapsedTime < duration) { + float q = (float) (elapsedTime) / duration; + + if (mInterpolator == null) { + q = viscousFluid(q); + } else { + q = mInterpolator.getInterpolation(q); + } + + mScrollerX.updateScroll(q); + mScrollerY.updateScroll(q); + } else { + abortAnimation(); + } + break; + + case FLING_MODE: + if (!mScrollerX.mFinished) { + if (!mScrollerX.update()) { + if (!mScrollerX.continueWhenFinished()) { + mScrollerX.finish(); + } + } + } + + if (!mScrollerY.mFinished) { + if (!mScrollerY.update()) { + if (!mScrollerY.continueWhenFinished()) { + mScrollerY.finish(); + } + } + } + + break; + } + + return true; + } + + /** + * Start scrolling by providing a starting point and the distance to travel. + * The scroll will use the default value of 250 milliseconds for the + * duration. + * + * @param startX Starting horizontal scroll offset in pixels. Positive + * numbers will scroll the content to the left. + * @param startY Starting vertical scroll offset in pixels. Positive numbers + * will scroll the content up. + * @param dx Horizontal distance to travel. Positive numbers will scroll the + * content to the left. + * @param dy Vertical distance to travel. Positive numbers will scroll the + * content up. + */ + public void startScroll(int startX, int startY, int dx, int dy) { + startScroll(startX, startY, dx, dy, DEFAULT_DURATION); + } + + /** + * Start scrolling by providing a starting point and the distance to travel. + * + * @param startX Starting horizontal scroll offset in pixels. Positive + * numbers will scroll the content to the left. + * @param startY Starting vertical scroll offset in pixels. Positive numbers + * will scroll the content up. + * @param dx Horizontal distance to travel. Positive numbers will scroll the + * content to the left. + * @param dy Vertical distance to travel. Positive numbers will scroll the + * content up. + * @param duration Duration of the scroll in milliseconds. + */ + public void startScroll(int startX, int startY, int dx, int dy, int duration) { + mMode = SCROLL_MODE; + mScrollerX.startScroll(startX, dx, duration); + mScrollerY.startScroll(startY, dy, duration); + } + + /** + * Call this when you want to 'spring back' into a valid coordinate range. + * + * @param startX Starting X coordinate + * @param startY Starting Y coordinate + * @param minX Minimum valid X value + * @param maxX Maximum valid X value + * @param minY Minimum valid Y value + * @param maxY Minimum valid Y value + * @return true if a springback was initiated, false if startX and startY were + * already within the valid range. + */ + public boolean springBack(int startX, int startY, int minX, int maxX, int minY, int maxY) { + mMode = FLING_MODE; + + // Make sure both methods are called. + final boolean spingbackX = mScrollerX.springback(startX, minX, maxX); + final boolean spingbackY = mScrollerY.springback(startY, minY, maxY); + return spingbackX || spingbackY; + } + + public void fling(int startX, int startY, int velocityX, int velocityY, + int minX, int maxX, int minY, int maxY) { + fling(startX, startY, velocityX, velocityY, minX, maxX, minY, maxY, 0, 0); + } + + /** + * Start scrolling based on a fling gesture. The distance traveled will + * depend on the initial velocity of the fling. + * + * @param startX Starting point of the scroll (X) + * @param startY Starting point of the scroll (Y) + * @param velocityX Initial velocity of the fling (X) measured in pixels per + * second. + * @param velocityY Initial velocity of the fling (Y) measured in pixels per + * second + * @param minX Minimum X value. The scroller will not scroll past this point + * unless overX > 0. If overfling is allowed, it will use minX as + * a springback boundary. + * @param maxX Maximum X value. The scroller will not scroll past this point + * unless overX > 0. If overfling is allowed, it will use maxX as + * a springback boundary. + * @param minY Minimum Y value. The scroller will not scroll past this point + * unless overY > 0. If overfling is allowed, it will use minY as + * a springback boundary. + * @param maxY Maximum Y value. The scroller will not scroll past this point + * unless overY > 0. If overfling is allowed, it will use maxY as + * a springback boundary. + * @param overX Overfling range. If > 0, horizontal overfling in either + * direction will be possible. + * @param overY Overfling range. If > 0, vertical overfling in either + * direction will be possible. + */ + public void fling(int startX, int startY, int velocityX, int velocityY, + int minX, int maxX, int minY, int maxY, int overX, int overY) { + // Continue a scroll or fling in progress + if (mFlywheel && !isFinished()) { + float oldVelocityX = mScrollerX.mCurrVelocity; + float oldVelocityY = mScrollerY.mCurrVelocity; + if (Math.signum(velocityX) == Math.signum(oldVelocityX) && + Math.signum(velocityY) == Math.signum(oldVelocityY)) { + velocityX += oldVelocityX; + velocityY += oldVelocityY; + } + } + + mMode = FLING_MODE; + mScrollerX.fling(startX, velocityX, minX, maxX, overX); + mScrollerY.fling(startY, velocityY, minY, maxY, overY); + } + + /** + * Notify the scroller that we've reached a horizontal boundary. + * Normally the information to handle this will already be known + * when the animation is started, such as in a call to one of the + * fling functions. However there are cases where this cannot be known + * in advance. This function will transition the current motion and + * animate from startX to finalX as appropriate. + * + * @param startX Starting/current X position + * @param finalX Desired final X position + * @param overX Magnitude of overscroll allowed. This should be the maximum + * desired distance from finalX. Absolute value - must be positive. + */ + public void notifyHorizontalEdgeReached(int startX, int finalX, int overX) { + mScrollerX.notifyEdgeReached(startX, finalX, overX); + } + + /** + * Notify the scroller that we've reached a vertical boundary. + * Normally the information to handle this will already be known + * when the animation is started, such as in a call to one of the + * fling functions. However there are cases where this cannot be known + * in advance. This function will animate a parabolic motion from + * startY to finalY. + * + * @param startY Starting/current Y position + * @param finalY Desired final Y position + * @param overY Magnitude of overscroll allowed. This should be the maximum + * desired distance from finalY. Absolute value - must be positive. + */ + public void notifyVerticalEdgeReached(int startY, int finalY, int overY) { + mScrollerY.notifyEdgeReached(startY, finalY, overY); + } + + public void notifyFinalXExtended(int finalX) { + mScrollerX.notifyFinalPositionExtended(finalX); + } + + public void notifyFinalYExtended(int finalY) { + mScrollerY.notifyFinalPositionExtended(finalY); + } + + /** + * Returns whether the current Scroller is currently returning to a valid position. + * Valid bounds were provided by the + * {@link #fling(int, int, int, int, int, int, int, int, int, int)} method. + * + * One should check this value before calling + * {@link #startScroll(int, int, int, int)} as the interpolation currently in progress + * to restore a valid position will then be stopped. The caller has to take into account + * the fact that the started scroll will start from an overscrolled position. + * + * @return true when the current position is overscrolled and in the process of + * interpolating back to a valid value. + */ + public boolean isOverScrolled() { + return ((!mScrollerX.mFinished && + mScrollerX.mState != SplineOverScroller.SPLINE) || + (!mScrollerY.mFinished && + mScrollerY.mState != SplineOverScroller.SPLINE)); + } + + /** + * Stops the animation. Contrary to {@link #forceFinished(boolean)}, + * aborting the animating causes the scroller to move to the final x and y + * positions. + * + * @see #forceFinished(boolean) + */ + public void abortAnimation() { + mScrollerX.finish(); + mScrollerY.finish(); + } + + /** + * Returns the time elapsed since the beginning of the scrolling. + * + * @return The elapsed time in milliseconds. + * + * @hide + */ + public int timePassed() { + final long time = AnimationUtils.currentAnimationTimeMillis(); + final long startTime = Math.min(mScrollerX.mStartTime, mScrollerY.mStartTime); + return (int) (time - startTime); + } + + /** + * @hide + */ + public boolean isScrollingInDirection(float xvel, float yvel) { + final int dx = mScrollerX.mFinal - mScrollerX.mStart; + final int dy = mScrollerY.mFinal - mScrollerY.mStart; + return !isFinished() && Math.signum(xvel) == Math.signum(dx) && + Math.signum(yvel) == Math.signum(dy); + } + + static class SplineOverScroller { + // Initial position + private int mStart; + + // Current position + private int mCurrentPosition; + + // Final position + private int mFinal; + + // Initial velocity + private int mVelocity; + + // Current velocity + private float mCurrVelocity; + + // Constant current deceleration + private float mDeceleration; + + // Animation starting time, in system milliseconds + private long mStartTime; + + // Animation duration, in milliseconds + private int mDuration; + + // Duration to complete spline component of animation + private int mSplineDuration; + + // Distance to travel along spline animation + private int mSplineDistance; + + // Whether the animation is currently in progress + private boolean mFinished; + + // The allowed overshot distance before boundary is reached. + private int mOver; + + // Fling friction + private float mFlingFriction = ViewConfiguration.getScrollFriction(); + + // Current state of the animation. + private int mState = SPLINE; + + // Constant gravity value, used in the deceleration phase. + private static final float GRAVITY = 2000.0f; + + // A context-specific coefficient adjusted to physical values. + private float mPhysicalCoeff; + + private static float DECELERATION_RATE = (float) (Math.log(0.78) / Math.log(0.9)); + private static final float INFLEXION = 0.35f; // Tension lines cross at (INFLEXION, 1) + private static final float START_TENSION = 0.5f; + private static final float END_TENSION = 1.0f; + private static final float P1 = START_TENSION * INFLEXION; + private static final float P2 = 1.0f - END_TENSION * (1.0f - INFLEXION); + + private static final int NB_SAMPLES = 100; + private static final float[] SPLINE_POSITION = new float[NB_SAMPLES + 1]; + private static final float[] SPLINE_TIME = new float[NB_SAMPLES + 1]; + + private static final int SPLINE = 0; + private static final int CUBIC = 1; + private static final int BALLISTIC = 2; + + static { + float x_min = 0.0f; + float y_min = 0.0f; + for (int i = 0; i < NB_SAMPLES; i++) { + final float alpha = (float) i / NB_SAMPLES; + + float x_max = 1.0f; + float x, tx, coef; + while (true) { + x = x_min + (x_max - x_min) / 2.0f; + coef = 3.0f * x * (1.0f - x); + tx = coef * ((1.0f - x) * P1 + x * P2) + x * x * x; + if (Math.abs(tx - alpha) < 1E-5) break; + if (tx > alpha) x_max = x; + else x_min = x; + } + SPLINE_POSITION[i] = coef * ((1.0f - x) * START_TENSION + x) + x * x * x; + + float y_max = 1.0f; + float y, dy; + while (true) { + y = y_min + (y_max - y_min) / 2.0f; + coef = 3.0f * y * (1.0f - y); + dy = coef * ((1.0f - y) * START_TENSION + y) + y * y * y; + if (Math.abs(dy - alpha) < 1E-5) break; + if (dy > alpha) y_max = y; + else y_min = y; + } + SPLINE_TIME[i] = coef * ((1.0f - y) * P1 + y * P2) + y * y * y; + } + SPLINE_POSITION[NB_SAMPLES] = SPLINE_TIME[NB_SAMPLES] = 1.0f; + + // This controls the viscous fluid effect (how much of it) + sViscousFluidScale = 8.0f; + // must be set to 1.0 (used in viscousFluid()) + sViscousFluidNormalize = 1.0f; + sViscousFluidNormalize = 1.0f / viscousFluid(1.0f); + } + + void setFriction(float friction) { + mFlingFriction = friction; + } + + SplineOverScroller(Context context) { + mFinished = true; + final float ppi = context.getResources().getDisplayMetrics().density * 160.0f; + mPhysicalCoeff = SensorManager.GRAVITY_EARTH // g (m/s^2) + * 39.37f // inch/meter + * ppi + * 0.84f; // look and feel tuning + } + + void updateScroll(float q) { + mCurrentPosition = mStart + Math.round(q * (mFinal - mStart)); + } + + /* + * Get a signed deceleration that will reduce the velocity. + */ + static private float getDeceleration(int velocity) { + return velocity > 0 ? -GRAVITY : GRAVITY; + } + + /* + * Modifies mDuration to the duration it takes to get from start to newFinal using the + * spline interpolation. The previous duration was needed to get to oldFinal. + */ + private void adjustDuration(int start, int oldFinal, int newFinal) { + final int oldDistance = oldFinal - start; + final int newDistance = newFinal - start; + final float x = Math.abs((float) newDistance / oldDistance); + final int index = (int) (NB_SAMPLES * x); + if (index < NB_SAMPLES) { + final float x_inf = (float) index / NB_SAMPLES; + final float x_sup = (float) (index + 1) / NB_SAMPLES; + final float t_inf = SPLINE_TIME[index]; + final float t_sup = SPLINE_TIME[index + 1]; + final float timeCoef = t_inf + (x - x_inf) / (x_sup - x_inf) * (t_sup - t_inf); + mDuration *= timeCoef; + } + } + + void startScroll(int start, int distance, int duration) { + mFinished = false; + + mStart = start; + mFinal = start + distance; + + mStartTime = AnimationUtils.currentAnimationTimeMillis(); + mDuration = duration; + + // Unused + mDeceleration = 0.0f; + mVelocity = 0; + } + + void finish() { + mCurrentPosition = mFinal; + // Not reset since WebView relies on this value for fast fling. + // TODO: restore when WebView uses the fast fling implemented in this class. + // mCurrVelocity = 0.0f; + mFinished = true; + } + + void setFinalPosition(int position) { + mFinal = position; + mFinished = false; + } + + void extendDuration(int extend) { + final long time = AnimationUtils.currentAnimationTimeMillis(); + final int elapsedTime = (int) (time - mStartTime); + mDuration = elapsedTime + extend; + mFinished = false; + } + + boolean springback(int start, int min, int max) { + mFinished = true; + + mStart = mFinal = start; + mVelocity = 0; + + mStartTime = AnimationUtils.currentAnimationTimeMillis(); + mDuration = 0; + + if (start < min) { + startSpringback(start, min, 0); + } else if (start > max) { + startSpringback(start, max, 0); + } + + return !mFinished; + } + + private void startSpringback(int start, int end, int velocity) { + // mStartTime has been set + mFinished = false; + mState = CUBIC; + mStart = start; + mFinal = end; + final int delta = start - end; + mDeceleration = getDeceleration(delta); + // TODO take velocity into account + mVelocity = -delta; // only sign is used + mOver = Math.abs(delta); + mDuration = (int) (1000.0 * Math.sqrt(-2.0 * delta / mDeceleration)); + } + + void fling(int start, int velocity, int min, int max, int over) { + mOver = over; + mFinished = false; + mCurrVelocity = mVelocity = velocity; + mDuration = mSplineDuration = 0; + mStartTime = AnimationUtils.currentAnimationTimeMillis(); + mCurrentPosition = mStart = start; + + if (start > max || start < min) { + startAfterEdge(start, min, max, velocity); + return; + } + + mState = SPLINE; + double totalDistance = 0.0; + + if (velocity != 0) { + mDuration = mSplineDuration = getSplineFlingDuration(velocity); + totalDistance = getSplineFlingDistance(velocity); + } + + mSplineDistance = (int) (totalDistance * Math.signum(velocity)); + mFinal = start + mSplineDistance; + + // Clamp to a valid final position + if (mFinal < min) { + adjustDuration(mStart, mFinal, min); + mFinal = min; + } + + if (mFinal > max) { + adjustDuration(mStart, mFinal, max); + mFinal = max; + } + } + + private double getSplineDeceleration(int velocity) { + return Math.log(INFLEXION * Math.abs(velocity) / (mFlingFriction * mPhysicalCoeff)); + } + + private double getSplineFlingDistance(int velocity) { + final double l = getSplineDeceleration(velocity); + final double decelMinusOne = DECELERATION_RATE - 1.0; + return mFlingFriction * mPhysicalCoeff * Math.exp(DECELERATION_RATE / decelMinusOne * l); + } + + /* Returns the duration, expressed in milliseconds */ + private int getSplineFlingDuration(int velocity) { + final double l = getSplineDeceleration(velocity); + final double decelMinusOne = DECELERATION_RATE - 1.0; + return (int) (1000.0 * Math.exp(l / decelMinusOne)); + } + + private void fitOnBounceCurve(int start, int end, int velocity) { + // Simulate a bounce that started from edge + final float durationToApex = - velocity / mDeceleration; + final float distanceToApex = velocity * velocity / 2.0f / Math.abs(mDeceleration); + final float distanceToEdge = Math.abs(end - start); + final float totalDuration = (float) Math.sqrt( + 2.0 * (distanceToApex + distanceToEdge) / Math.abs(mDeceleration)); + mStartTime -= (int) (1000.0f * (totalDuration - durationToApex)); + mStart = end; + mVelocity = (int) (- mDeceleration * totalDuration); + } + + private void startBounceAfterEdge(int start, int end, int velocity) { + mDeceleration = getDeceleration(velocity == 0 ? start - end : velocity); + fitOnBounceCurve(start, end, velocity); + onEdgeReached(); + } + + private void startAfterEdge(int start, int min, int max, int velocity) { + if (start > min && start < max) { + Log.e("VelocityScroller", "startAfterEdge called from a valid position"); + mFinished = true; + return; + } + final boolean positive = start > max; + final int edge = positive ? max : min; + final int overDistance = start - edge; + boolean keepIncreasing = overDistance * velocity >= 0; + if (keepIncreasing) { + // Will result in a bounce or a to_boundary depending on velocity. + startBounceAfterEdge(start, edge, velocity); + } else { + final double totalDistance = getSplineFlingDistance(velocity); + if (totalDistance > Math.abs(overDistance)) { + fling(start, velocity, positive ? min : start, positive ? start : max, mOver); + } else { + startSpringback(start, edge, velocity); + } + } + } + + void notifyEdgeReached(int start, int end, int over) { + // mState is used to detect successive notifications + if (mState == SPLINE) { + mOver = over; + mStartTime = AnimationUtils.currentAnimationTimeMillis(); + // We were in fling/scroll mode before: current velocity is such that distance to + // edge is increasing. This ensures that startAfterEdge will not start a new fling. + startAfterEdge(start, end, end, (int) mCurrVelocity); + } + } + + // TODO: Don't discard current velocity, use spline interpolation instead. + public void notifyFinalPositionExtended(int position) { + mOver = 0; + mFinished = false; + mDuration = mDuration - (int) (mStartTime - AnimationUtils.currentAnimationTimeMillis()); + + if (mDuration < 50) { + mDuration = 50; + } + + mSplineDuration = mDuration; + + mStartTime = AnimationUtils.currentAnimationTimeMillis(); + mStart = mCurrentPosition; + mFinal = position; + + mState = SPLINE; + + mSplineDistance = mFinal - mStart; + } + + private void onEdgeReached() { + // mStart, mVelocity and mStartTime were adjusted to their values when edge was reached. + float distance = mVelocity * mVelocity / (2.0f * Math.abs(mDeceleration)); + final float sign = Math.signum(mVelocity); + + if (distance > mOver) { + // Default deceleration is not sufficient to slow us down before boundary + mDeceleration = - sign * mVelocity * mVelocity / (2.0f * mOver); + distance = mOver; + } + + mOver = (int) distance; + mState = BALLISTIC; + mFinal = mStart + (int) (mVelocity > 0 ? distance : -distance); + mDuration = - (int) (1000.0f * mVelocity / mDeceleration); + } + + boolean continueWhenFinished() { + switch (mState) { + case SPLINE: + // Duration from start to null velocity + if (mDuration < mSplineDuration) { + // If the animation was clamped, we reached the edge + mStart = mFinal; + // TODO Better compute speed when edge was reached + mVelocity = (int) mCurrVelocity; + mDeceleration = getDeceleration(mVelocity); + mStartTime += mDuration; + onEdgeReached(); + } else { + // Normal stop, no need to continue + return false; + } + break; + case BALLISTIC: + mStartTime += mDuration; + startSpringback(mFinal, mStart, 0); + break; + case CUBIC: + return false; + } + + update(); + return true; + } + + /* + * Update the current position and velocity for current time. Returns + * true if update has been done and false if animation duration has been + * reached. + */ + boolean update() { + final long time = AnimationUtils.currentAnimationTimeMillis(); + final long currentTime = time - mStartTime; + + if (currentTime > mDuration) { + return false; + } + + double distance = 0.0; + switch (mState) { + case SPLINE: { + final float t = (float) currentTime / mSplineDuration; + final int index = (int) (NB_SAMPLES * t); + float distanceCoef = 1.f; + float velocityCoef = 0.f; + if (index < NB_SAMPLES) { + final float t_inf = (float) index / NB_SAMPLES; + final float t_sup = (float) (index + 1) / NB_SAMPLES; + final float d_inf = SPLINE_POSITION[index]; + final float d_sup = SPLINE_POSITION[index + 1]; + velocityCoef = (d_sup - d_inf) / (t_sup - t_inf); + distanceCoef = d_inf + (t - t_inf) * velocityCoef; + } + + distance = distanceCoef * mSplineDistance; + mCurrVelocity = velocityCoef * mSplineDistance / mSplineDuration * 1000.0f; + break; + } + + case BALLISTIC: { + final float t = currentTime / 1000.0f; + mCurrVelocity = mVelocity + mDeceleration * t; + distance = mVelocity * t + mDeceleration * t * t / 2.0f; + break; + } + + case CUBIC: { + final float t = (float) (currentTime) / mDuration; + final float t2 = t * t; + final float sign = Math.signum(mVelocity); + distance = sign * mOver * (3.0f * t2 - 2.0f * t * t2); + mCurrVelocity = sign * mOver * 6.0f * (- t + t2); + break; + } + } + + mCurrentPosition = mStart + (int) Math.round(distance); + + return true; + } + } +}
\ No newline at end of file diff --git a/src/au/com/glassechidna/velocityviewpager/VelocityViewPager.java b/src/au/com/glassechidna/velocityviewpager/VelocityViewPager.java new file mode 100644 index 0000000..7049514 --- /dev/null +++ b/src/au/com/glassechidna/velocityviewpager/VelocityViewPager.java @@ -0,0 +1,3101 @@ +/* + * Copyright (C) 2011 The Android Open Source Project + * Copyright (C) 2014 Benjamin Dobell, Glass Echidna + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package au.com.glassechidna.velocityviewpager; + +import android.content.Context; +import android.content.res.Resources; +import android.content.res.TypedArray; +import android.database.DataSetObserver; +import android.graphics.Canvas; +import android.graphics.Rect; +import android.graphics.drawable.Drawable; +import android.os.Build; +import android.os.Bundle; +import android.os.Parcel; +import android.os.Parcelable; +import android.os.SystemClock; +import android.support.v4.os.ParcelableCompat; +import android.support.v4.os.ParcelableCompatCreatorCallbacks; +import android.support.v4.view.AccessibilityDelegateCompat; +import android.support.v4.view.KeyEventCompat; +import android.support.v4.view.MotionEventCompat; +import android.support.v4.view.PagerAdapter; +import android.support.v4.view.VelocityTrackerCompat; +import android.support.v4.view.ViewCompat; +import android.support.v4.view.ViewConfigurationCompat; +import android.support.v4.view.accessibility.AccessibilityEventCompat; +import android.support.v4.view.accessibility.AccessibilityNodeInfoCompat; +import android.support.v4.view.accessibility.AccessibilityRecordCompat; +import android.support.v4.widget.EdgeEffectCompat; +import android.util.AttributeSet; +import android.util.Log; +import android.view.FocusFinder; +import android.view.Gravity; +import android.view.KeyEvent; +import android.view.MotionEvent; +import android.view.SoundEffectConstants; +import android.view.VelocityTracker; +import android.view.View; +import android.view.ViewConfiguration; +import android.view.ViewGroup; +import android.view.ViewParent; +import android.view.accessibility.AccessibilityEvent; +import android.view.animation.AnimationUtils; +import android.view.animation.Interpolator; + +import java.lang.reflect.Method; +import java.util.ArrayList; +import java.util.Collections; +import java.util.Comparator; + +/** + * Layout manager that allows the user to flip left and right + * through pages of data. You supply an implementation of a + * {@link android.support.v4.view.PagerAdapter} to generate the pages that the view shows. + * + * Based on the support library's ViewPager, this class includes + * modifications that add support continuous scrolling fling + * gestures and customised rendering logic to allow support for + * carousel-like behaviour. + */ +public class VelocityViewPager extends ViewGroup implements View.OnClickListener, View.OnLongClickListener { + private static final String TAG = "VelocityViewPager"; + private static final boolean DEBUG = false; + + private static final boolean USE_CACHE = false; + + private static final int DEFAULT_OFFSCREEN_PAGES = 1; + private static final int MAX_SETTLE_DURATION = 600; // ms + private static final int MIN_DISTANCE_FOR_FLING = 25; // dips + + private static final int DEFAULT_GUTTER_SIZE = 16; // dips + + private static final int MIN_FLING_VELOCITY = 400; // dips + + private static final int[] LAYOUT_ATTRS = new int[] { + android.R.attr.layout_gravity + }; + + /** + * Used to track what the expected number of items in the adapter should be. + * If the app changes this when we don't expect it, we'll throw a big obnoxious exception. + */ + private int mExpectedAdapterCount; + + static class ItemInfo { + Object object; + int position; + boolean scrolling; + float widthFactor; + float offset; + } + + private static final Comparator<ItemInfo> COMPARATOR = new Comparator<ItemInfo>(){ + @Override + public int compare(ItemInfo lhs, ItemInfo rhs) { + return lhs.position - rhs.position; + } + }; + + private static final Interpolator sInterpolator = new Interpolator() { + public float getInterpolation(float t) { + t -= 1.0f; + return t * t * t * t * t + 1.0f; + } + }; + + private static final int FLINGING_STOPPED = 0; + private static final int FLINGING_LEFT = 1; + private static final int FLINGING_RIGHT = 2; + + private final ArrayList<ItemInfo> mItems = new ArrayList<ItemInfo>(); + private final ItemInfo mTempItem = new ItemInfo(); + + private final Rect mTempRect = new Rect(); + + private PagerAdapter mAdapter; + private int mCurItem; // Index of currently displayed page. + private int mRestoredCurItem = -1; + private Parcelable mRestoredAdapterState = null; + private ClassLoader mRestoredClassLoader = null; + private VelocityScroller mScroller; + private PagerObserver mObserver; + + private int mPageMargin; + private Drawable mMarginDrawable; + private int mTopPageBounds; + private int mBottomPageBounds; + + // Offsets of the first and last items, if known. + // Set during population, used to determine if we are at the beginning + // or end of the pager data set during touch scrolling. + private float mFirstOffset = -Float.MAX_VALUE; + private float mLastOffset = Float.MAX_VALUE; + private boolean mOffsetToLastPageAllowed = false; + + private int mChildWidthMeasureSpec; + private int mChildHeightMeasureSpec; + private boolean mInLayout; + + private boolean mScrollingCacheEnabled; + + private int mOffscreenPageLimit = DEFAULT_OFFSCREEN_PAGES; + + private boolean mIsBeingDragged; + private boolean mIsUnableToDrag; + private boolean mIgnoreGutter; + private int mDefaultGutterSize; + private int mGutterSize; + private int mTouchSlop; + /** + * Position of the last motion event. + */ + private float mLastMotionX; + private float mLastMotionY; + private float mInitialMotionX; + private float mInitialMotionY; + /** + * ID of the active pointer. This is used to retain consistency during + * drags/flings if multiple pointers are used. + */ + private int mActivePointerId = INVALID_POINTER; + /** + * Sentinel value for no current active pointer. + * Used by {@link #mActivePointerId}. + */ + private static final int INVALID_POINTER = -1; + + /** + * Determines speed during touch scrolling + */ + private VelocityTracker mVelocityTracker; + private int mMinimumVelocity; + private int mMaximumVelocity; + private int mFlingDistance; + private int mCloseEnough; + private long mScrollStartTime; + private int mScrollDuration; + private int mFlinging; + + // If the pager is at least this close to its final position, complete the scroll + // on touch down and let the user interact with the content inside instead of + // "catching" the flinging pager. + private static final int CLOSE_ENOUGH = 2; // dp + + private boolean mFakeDragging; + private long mFakeDragBeginTime; + + private EdgeEffectCompat mLeftEdge; + private EdgeEffectCompat mRightEdge; + + private boolean mFirstLayout = true; + private boolean mNeedCalculatePageOffsets = false; + private boolean mCalledSuper; + private int mDecorChildCount; + + private OnPageChangeListener mOnPageChangeListener; + private OnPageChangeListener mInternalPageChangeListener; + private OnAdapterChangeListener mAdapterChangeListener; + private PageTransformer mPageTransformer; + private Method mSetChildrenDrawingOrderEnabled; + + private static final int DRAW_ORDER_DEFAULT = 0; + private static final int DRAW_ORDER_FORWARD = 1; + private static final int DRAW_ORDER_REVERSE = 2; + private int mDrawingOrder; + private ArrayList<View> mDrawingOrderedChildren; + private Comparator<View> mDrawOrderComparator = new ViewPositionComparator(); + + private OnItemClickListener mOnItemClickListener; + private OnItemLongClickListener mOnItemLongClickListener; + + /** + * Indicates that the pager is in an idle, settled state. The current page + * is fully in view and no animation is in progress. + */ + public static final int SCROLL_STATE_IDLE = 0; + + /** + * Indicates that the pager is currently being dragged by the user. + */ + public static final int SCROLL_STATE_DRAGGING = 1; + + /** + * Indicates that the pager is in the process of settling to a final position. + */ + public static final int SCROLL_STATE_SETTLING = 2; + + private final Runnable mEndScrollRunnable = new Runnable() { + public void run() { + setScrollState(SCROLL_STATE_IDLE); + populate(); + } + }; + + private int mScrollState = SCROLL_STATE_IDLE; + + /** + * Callback interface for responding to changing state of the selected page. + */ + public interface OnPageChangeListener { + + /** + * This method will be invoked when the current page is scrolled, either as part + * of a programmatically initiated smooth scroll or a user initiated touch scroll. + * + * @param position Position index of the first page currently being displayed. + * Page position+1 will be visible if positionOffset is nonzero. + * @param positionOffset Value from [0, 1) indicating the offset from the page at position. + * @param positionOffsetPixels Value in pixels indicating the offset from position. + */ + public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels); + + /** + * This method will be invoked when a new page becomes selected. Animation is not + * necessarily complete. + * + * @param position Position index of the new selected page. + */ + public void onPageSelected(int position); + + /** + * Called when the scroll state changes. Useful for discovering when the user + * begins dragging, when the pager is automatically settling to the current page, + * or when it is fully stopped/idle. + * + * @param state The new scroll state. + * @see VelocityViewPager#SCROLL_STATE_IDLE + * @see VelocityViewPager#SCROLL_STATE_DRAGGING + * @see VelocityViewPager#SCROLL_STATE_SETTLING + */ + public void onPageScrollStateChanged(int state); + } + + /** + * Simple implementation of the {@link OnPageChangeListener} interface with stub + * implementations of each method. Extend this if you do not intend to override + * every method of {@link OnPageChangeListener}. + */ + public static class SimpleOnPageChangeListener implements OnPageChangeListener { + @Override + public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { + // This space for rent + } + + @Override + public void onPageSelected(int position) { + // This space for rent + } + + @Override + public void onPageScrollStateChanged(int state) { + // This space for rent + } + } + + /** + * Default view rendering order comparator identical to that used in the + * support library's ViewPager. + */ + public static class ViewPositionComparator implements Comparator<View> { + @Override + public int compare(View lhs, View rhs) { + final LayoutParams llp = (LayoutParams) lhs.getLayoutParams(); + final LayoutParams rlp = (LayoutParams) rhs.getLayoutParams(); + if (llp.isDecor != rlp.isDecor) { + return llp.isDecor ? 1 : -1; + } + return llp.position - rlp.position; + } + } + + /** + * A PageTransformer is invoked whenever a visible/attached page is scrolled. + * This offers an opportunity for the application to apply a custom transformation + * to the page views using animation properties. + * + * <p>As property animation is only supported as of Android 3.0 and forward, + * setting a PageTransformer on a ViewPager on earlier platform versions will + * be ignored.</p> + */ + public interface PageTransformer { + /** + * Apply a property transformation to the given page. + * + * @param page Apply the transformation to this page + * @param position Position of page relative to the current front-and-center + * position of the pager. 0 is front and center. 1 is one full + * page position to the right, and -1 is one page position to the left. + */ + public void transformPage(View page, float position); + } + + /** + * Used internally to monitor when adapters are switched. + */ + interface OnAdapterChangeListener { + public void onAdapterChanged(PagerAdapter oldAdapter, PagerAdapter newAdapter); + } + + /** + * Used internally to tag special types of child views that should be added as + * pager decorations by default. + */ + interface Decor {} + + public VelocityViewPager(Context context) { + super(context); + initViewPager(); + } + + public VelocityViewPager(Context context, AttributeSet attrs) { + super(context, attrs); + initViewPager(); + } + + void initViewPager() { + setWillNotDraw(false); + setDescendantFocusability(FOCUS_AFTER_DESCENDANTS); + setFocusable(true); + final Context context = getContext(); + mScroller = new VelocityScroller(context, sInterpolator); + final ViewConfiguration configuration = ViewConfiguration.get(context); + final float density = context.getResources().getDisplayMetrics().density; + + mTouchSlop = ViewConfigurationCompat.getScaledPagingTouchSlop(configuration); + mMinimumVelocity = (int) (MIN_FLING_VELOCITY * density); + mMaximumVelocity = configuration.getScaledMaximumFlingVelocity(); + mLeftEdge = new EdgeEffectCompat(context); + mRightEdge = new EdgeEffectCompat(context); + + mFlingDistance = (int) (MIN_DISTANCE_FOR_FLING * density); + mCloseEnough = (int) (CLOSE_ENOUGH * density); + mDefaultGutterSize = (int) (DEFAULT_GUTTER_SIZE * density); + + ViewCompat.setAccessibilityDelegate(this, new MyAccessibilityDelegate()); + + if (ViewCompat.getImportantForAccessibility(this) + == ViewCompat.IMPORTANT_FOR_ACCESSIBILITY_AUTO) { + ViewCompat.setImportantForAccessibility(this, + ViewCompat.IMPORTANT_FOR_ACCESSIBILITY_YES); + } + } + + @Override + protected void onDetachedFromWindow() { + removeCallbacks(mEndScrollRunnable); + super.onDetachedFromWindow(); + } + + private void setScrollState(int newState) { + if (mScrollState == newState) { + return; + } + + mScrollState = newState; + if (mPageTransformer != null) { + // PageTransformers can do complex things that benefit from hardware layers. + enableLayers(newState != SCROLL_STATE_IDLE); + } + if (mOnPageChangeListener != null) { + mOnPageChangeListener.onPageScrollStateChanged(newState); + } + + } + /** + * Set a PagerAdapter that will supply views for this pager as needed. + * + * @param adapter Adapter to use + */ + public void setAdapter(PagerAdapter adapter) { + if (mAdapter != null) { + mAdapter.unregisterDataSetObserver(mObserver); + mAdapter.startUpdate(this); + for (int i = 0; i < mItems.size(); i++) { + final ItemInfo ii = mItems.get(i); + mAdapter.destroyItem(this, ii.position, ii.object); + } + mAdapter.finishUpdate(this); + mItems.clear(); + removeNonDecorViews(); + mCurItem = 0; + scrollTo(0, 0); + } + + final PagerAdapter oldAdapter = mAdapter; + mAdapter = adapter; + mExpectedAdapterCount = 0; + + if (mAdapter != null) { + if (mObserver == null) { + mObserver = new PagerObserver(); + } + mAdapter.registerDataSetObserver(mObserver); + final boolean wasFirstLayout = mFirstLayout; + mFirstLayout = true; + mExpectedAdapterCount = mAdapter.getCount(); + if (mRestoredCurItem >= 0) { + mAdapter.restoreState(mRestoredAdapterState, mRestoredClassLoader); + setCurrentItemInternal(mRestoredCurItem, false, true); + mRestoredCurItem = -1; + mRestoredAdapterState = null; + mRestoredClassLoader = null; + } else if (!wasFirstLayout) { + populate(); + } else { + requestLayout(); + } + } + + if (mAdapterChangeListener != null && oldAdapter != adapter) { + mAdapterChangeListener.onAdapterChanged(oldAdapter, adapter); + } + } + + private void removeNonDecorViews() { + for (int i = 0; i < getChildCount(); i++) { + final View child = getChildAt(i); + final LayoutParams lp = (LayoutParams) child.getLayoutParams(); + if (!lp.isDecor) { + removeViewAt(i); + i--; + } + } + } + + /** + * Retrieve the current adapter supplying pages. + * + * @return The currently registered PagerAdapter + */ + public PagerAdapter getAdapter() { + return mAdapter; + } + + void setOnAdapterChangeListener(OnAdapterChangeListener listener) { + mAdapterChangeListener = listener; + } + + private int getClientWidth() { + return getMeasuredWidth() - getPaddingLeft() - getPaddingRight(); + } + + /** + * Set the currently selected page. If the ViewPager has already been through its first + * layout with its current adapter there will be a smooth animated transition between + * the current item and the specified item. + * + * @param item Item index to select + */ + public void setCurrentItem(int item) { + setCurrentItemInternal(item, !mFirstLayout, false); + } + + /** + * Set the currently selected page. + * + * @param item Item index to select + * @param smoothScroll True to smoothly scroll to the new item, false to transition immediately + */ + public void setCurrentItem(int item, boolean smoothScroll) { + setCurrentItemInternal(item, smoothScroll, false); + } + + public int getCurrentItem() { + return mCurItem; + } + + void setCurrentItemInternal(int item, boolean smoothScroll, boolean always) { + setCurrentItemInternal(item, smoothScroll, always, 0); + } + + void setCurrentItemInternal(int item, boolean smoothScroll, boolean always, int velocity) { + if (mAdapter == null || mAdapter.getCount() <= 0) { + setScrollingCacheEnabled(false); + return; + } + if (!always && mCurItem == item && mItems.size() != 0) { + setScrollingCacheEnabled(false); + return; + } + + if (item < 0) { + item = 0; + } else if (item >= mAdapter.getCount()) { + item = mAdapter.getCount() - 1; + } + final int pageLimit = mOffscreenPageLimit; + if (item > (mCurItem + pageLimit) || item < (mCurItem - pageLimit)) { + // We are doing a jump by more than one page. To avoid + // glitches, we want to keep all current pages in the view + // until the scroll ends. + for (int i=0; i<mItems.size(); i++) { + mItems.get(i).scrolling = true; + } + } + final boolean dispatchSelected = mCurItem != item; + + if (mFirstLayout) { + // We don't have any idea how big we are yet and shouldn't have any pages either. + // Just set things up and let the pending layout handle things. + mCurItem = item; + if (dispatchSelected && mOnPageChangeListener != null) { + mOnPageChangeListener.onPageSelected(item); + } + if (dispatchSelected && mInternalPageChangeListener != null) { + mInternalPageChangeListener.onPageSelected(item); + } + requestLayout(); + } else { + populate(item); + scrollToItem(item, smoothScroll, velocity, dispatchSelected); + } + } + + private void scrollToItem(int item, boolean smoothScroll, int velocity, + boolean dispatchSelected) { + final ItemInfo curInfo = infoForPosition(item); + int destX = 0; + if (curInfo != null) { + final int width = getClientWidth(); + destX = (int) (width * Math.max(mFirstOffset, + Math.min(curInfo.offset, mLastOffset))); + } + if (smoothScroll) { + smoothScrollTo(destX, 0, velocity); + if (dispatchSelected && mOnPageChangeListener != null) { + mOnPageChangeListener.onPageSelected(item); + } + if (dispatchSelected && mInternalPageChangeListener != null) { + mInternalPageChangeListener.onPageSelected(item); + } + } else { + if (dispatchSelected && mOnPageChangeListener != null) { + mOnPageChangeListener.onPageSelected(item); + } + if (dispatchSelected && mInternalPageChangeListener != null) { + mInternalPageChangeListener.onPageSelected(item); + } + completeScroll(false); + scrollTo(destX, 0); + pageScrolled(destX); + } + } + + /** + * Set a listener that will be invoked whenever the page changes or is incrementally + * scrolled. See {@link OnPageChangeListener}. + * + * @param listener Listener to set + */ + public void setOnPageChangeListener(OnPageChangeListener listener) { + mOnPageChangeListener = listener; + } + + /** + * Set a {@link PageTransformer} that will be called for each attached page whenever + * the scroll position is changed. This allows the application to apply custom property + * transformations to each page, overriding the default sliding look and feel. + * + * <p><em>Note:</em> Prior to Android 3.0 the property animation APIs did not exist. + * As a result, setting a PageTransformer prior to Android 3.0 (API 11) will have no effect.</p> + * + * @param reverseDrawingOrder true if the supplied PageTransformer requires page views + * to be drawn from last to first instead of first to last. + * @param transformer PageTransformer that will modify each page's animation properties + */ + public void setPageTransformer(boolean reverseDrawingOrder, PageTransformer transformer) { + if (Build.VERSION.SDK_INT >= 11) { + final boolean hasTransformer = transformer != null; + final boolean needsPopulate = hasTransformer != (mPageTransformer != null); + mPageTransformer = transformer; + setChildrenDrawingOrderEnabledCompat(hasTransformer); + if (hasTransformer) { + mDrawingOrder = reverseDrawingOrder ? DRAW_ORDER_REVERSE : DRAW_ORDER_FORWARD; + } else { + mDrawingOrder = DRAW_ORDER_DEFAULT; + } + if (needsPopulate) populate(); + } + } + + public void setDrawOrderComparator(Comparator<View> drawOrderComparator) { + this.mDrawOrderComparator = drawOrderComparator; + } + + public void setOffsetToLastPageAllowed(final boolean offsetToLastPageAllowed) { + this.mOffsetToLastPageAllowed = offsetToLastPageAllowed; + } + + void setChildrenDrawingOrderEnabledCompat(boolean enable) { + if (Build.VERSION.SDK_INT >= 7) { + if (mSetChildrenDrawingOrderEnabled == null) { + try { + mSetChildrenDrawingOrderEnabled = ViewGroup.class.getDeclaredMethod( + "setChildrenDrawingOrderEnabled", new Class[] { Boolean.TYPE }); + } catch (NoSuchMethodException e) { + Log.e(TAG, "Can't find setChildrenDrawingOrderEnabled", e); + } + } + try { + mSetChildrenDrawingOrderEnabled.invoke(this, enable); + } catch (Exception e) { + Log.e(TAG, "Error changing children drawing order", e); + } + } + } + + @Override + protected int getChildDrawingOrder(int childCount, int i) { + final int index = mDrawingOrder == DRAW_ORDER_REVERSE ? childCount - 1 - i : i; + final int result = ((LayoutParams) mDrawingOrderedChildren.get(index).getLayoutParams()).childIndex; + return result; + } + + /** + * Set a separate OnPageChangeListener for internal use by the support library. + * + * @param listener Listener to set + * @return The old listener that was set, if any. + */ + OnPageChangeListener setInternalPageChangeListener(OnPageChangeListener listener) { + OnPageChangeListener oldListener = mInternalPageChangeListener; + mInternalPageChangeListener = listener; + return oldListener; + } + + /** + * Returns the number of pages that will be retained to either side of the + * current page in the view hierarchy in an idle state. Defaults to 1. + * + * @return How many pages will be kept offscreen on either side + * @see #setOffscreenPageLimit(int) + */ + public int getOffscreenPageLimit() { + return mOffscreenPageLimit; + } + + /** + * Set the number of pages that should be retained to either side of the + * current page in the view hierarchy in an idle state. Pages beyond this + * limit will be recreated from the adapter when needed. + * + * <p>This is offered as an optimization. If you know in advance the number + * of pages you will need to support or have lazy-loading mechanisms in place + * on your pages, tweaking this setting can have benefits in perceived smoothness + * of paging animations and interaction. If you have a small number of pages (3-4) + * that you can keep active all at once, less time will be spent in layout for + * newly created view subtrees as the user pages back and forth.</p> + * + * <p>You should keep this limit low, especially if your pages have complex layouts. + * This setting defaults to 1.</p> + * + * @param limit How many pages will be kept offscreen in an idle state. + */ + public void setOffscreenPageLimit(int limit) { + if (limit < DEFAULT_OFFSCREEN_PAGES) { + Log.w(TAG, "Requested offscreen page limit " + limit + " too small; defaulting to " + + DEFAULT_OFFSCREEN_PAGES); + limit = DEFAULT_OFFSCREEN_PAGES; + } + if (limit != mOffscreenPageLimit) { + mOffscreenPageLimit = limit; + populate(); + } + } + + /** + * Set the margin between pages. + * + * @param marginPixels Distance between adjacent pages in pixels + * @see #getPageMargin() + * @see #setPageMarginDrawable(android.graphics.drawable.Drawable) + * @see #setPageMarginDrawable(int) + */ + public void setPageMargin(int marginPixels) { + final int oldMargin = mPageMargin; + mPageMargin = marginPixels; + + final int width = getWidth(); + recomputeScrollPosition(width, width, marginPixels, oldMargin); + + requestLayout(); + } + + /** + * Return the margin between pages. + * + * @return The size of the margin in pixels + */ + public int getPageMargin() { + return mPageMargin; + } + + /** + * Set a drawable that will be used to fill the margin between pages. + * + * @param d Drawable to display between pages + */ + public void setPageMarginDrawable(Drawable d) { + mMarginDrawable = d; + if (d != null) refreshDrawableState(); + setWillNotDraw(d == null); + invalidate(); + } + + /** + * Set a drawable that will be used to fill the margin between pages. + * + * @param resId Resource ID of a drawable to display between pages + */ + public void setPageMarginDrawable(int resId) { + setPageMarginDrawable(getContext().getResources().getDrawable(resId)); + } + + @Override + protected boolean verifyDrawable(Drawable who) { + return super.verifyDrawable(who) || who == mMarginDrawable; + } + + @Override + protected void drawableStateChanged() { + super.drawableStateChanged(); + final Drawable d = mMarginDrawable; + if (d != null && d.isStateful()) { + d.setState(getDrawableState()); + } + } + + // We want the duration of the page snap animation to be influenced by the distance that + // the screen has to travel, however, we don't want this duration to be effected in a + // purely linear fashion. Instead, we use this method to moderate the effect that the distance + // of travel has on the overall snap duration. + float distanceInfluenceForSnapDuration(float f) { + f -= 0.5f; // center the values about 0. + f *= 0.3f * Math.PI / 2.0f; + return (float) Math.sin(f); + } + + /** + * Like {@link android.view.View#scrollBy}, but scroll smoothly instead of immediately. + * + * @param x the number of pixels to scroll by on the X axis + * @param y the number of pixels to scroll by on the Y axis + */ + void smoothScrollTo(int x, int y) { + smoothScrollTo(x, y, 0); + } + + /** + * Like {@link android.view.View#scrollBy}, but scroll smoothly instead of immediately. + * + * @param x the number of pixels to scroll by on the X axis + * @param y the number of pixels to scroll by on the Y axis + * @param velocity the velocity associated with a fling, if applicable. (0 otherwise) + */ + void smoothScrollTo(int x, int y, int velocity) { + if (getChildCount() == 0) { + // Nothing to do. + setScrollingCacheEnabled(false); + return; + } + int sx = getScrollX(); + int sy = getScrollY(); + int dx = x - sx; + int dy = y - sy; + if (dx == 0 && dy == 0) { + completeScroll(false); + populate(); + setScrollState(SCROLL_STATE_IDLE); + return; + } + + setScrollingCacheEnabled(true); + setScrollState(SCROLL_STATE_SETTLING); + + final int width = getClientWidth(); + final int halfWidth = width / 2; + final float distanceRatio = Math.min(1f, 1.0f * Math.abs(dx) / width); + final float distance = halfWidth + halfWidth * + distanceInfluenceForSnapDuration(distanceRatio); + + int duration = 0; + velocity = Math.abs(velocity); + if (velocity > 0) { + duration = 4 * Math.round(1000 * Math.abs(distance / velocity)); + } else { + final float pageWidth = width * mAdapter.getPageWidth(mCurItem); + final float pageDelta = (float) Math.abs(dx) / (pageWidth + mPageMargin); + duration = (int) ((pageDelta + 1) * 100); + } + duration = Math.min(duration, MAX_SETTLE_DURATION); + + mScrollStartTime = AnimationUtils.currentAnimationTimeMillis(); + mScrollDuration = duration; + mScroller.startScroll(sx, sy, dx, dy, duration); + ViewCompat.postInvalidateOnAnimation(this); + } + + ItemInfo addNewItem(int position, int index) { + ItemInfo ii = new ItemInfo(); + ii.position = position; + ii.object = mAdapter.instantiateItem(this, position); + ii.widthFactor = mAdapter.getPageWidth(position); + if (index < 0 || index >= mItems.size()) { + mItems.add(ii); + } else { + mItems.add(index, ii); + } + return ii; + } + + void dataSetChanged() { + // This method only gets called if our observer is attached, so mAdapter is non-null. + + final int adapterCount = mAdapter.getCount(); + mExpectedAdapterCount = adapterCount; + boolean needPopulate = mItems.size() < mOffscreenPageLimit * 2 + 1 && + mItems.size() < adapterCount; + int newCurrItem = mCurItem; + + boolean isUpdating = false; + for (int i = 0; i < mItems.size(); i++) { + final ItemInfo ii = mItems.get(i); + final int newPos = mAdapter.getItemPosition(ii.object); + + if (newPos == PagerAdapter.POSITION_UNCHANGED) { + continue; + } + + if (newPos == PagerAdapter.POSITION_NONE) { + mItems.remove(i); + i--; + + if (!isUpdating) { + mAdapter.startUpdate(this); + isUpdating = true; + } + + mAdapter.destroyItem(this, ii.position, ii.object); + needPopulate = true; + + if (mCurItem == ii.position) { + // Keep the current item in the valid range + newCurrItem = Math.max(0, Math.min(mCurItem, adapterCount - 1)); + needPopulate = true; + } + continue; + } + + if (ii.position != newPos) { + if (ii.position == mCurItem) { + // Our current item changed position. Follow it. + newCurrItem = newPos; + } + + ii.position = newPos; + needPopulate = true; + } + } + + if (isUpdating) { + mAdapter.finishUpdate(this); + + updateViewOnClickListeners(); + updateViewOnLongClickListeners(); + } + + Collections.sort(mItems, COMPARATOR); + + if (needPopulate) { + // Reset our known page widths; populate will recompute them. + final int childCount = getChildCount(); + for (int i = 0; i < childCount; i++) { + final View child = getChildAt(i); + final LayoutParams lp = (LayoutParams) child.getLayoutParams(); + if (!lp.isDecor) { + lp.widthFactor = 0.f; + } + } + + setCurrentItemInternal(newCurrItem, false, true); + requestLayout(); + } + } + + void populate() { + populate(mCurItem); + } + + void populate(int newCurrentItem) { + ItemInfo oldCurInfo = null; + int focusDirection = View.FOCUS_FORWARD; + if (mCurItem != newCurrentItem) { + focusDirection = mCurItem < newCurrentItem ? View.FOCUS_RIGHT : View.FOCUS_LEFT; + oldCurInfo = infoForPosition(mCurItem); + mCurItem = newCurrentItem; + } + + if (mAdapter == null) { + sortChildDrawingOrder(); + return; + } + + // Also, don't populate until we are attached to a window. This is to + // avoid trying to populate before we have restored our view hierarchy + // state and conflicting with what is restored. + if (getWindowToken() == null) { + return; + } + + mAdapter.startUpdate(this); + + final int pageLimit = mOffscreenPageLimit; + final int startPos = Math.max(0, mCurItem - pageLimit); + final int N = mAdapter.getCount(); + final int endPos = Math.min(N - 1, mCurItem + pageLimit); + + if (N != mExpectedAdapterCount) { + String resName; + try { + resName = getResources().getResourceName(getId()); + } catch (Resources.NotFoundException e) { + resName = Integer.toHexString(getId()); + } + throw new IllegalStateException("The application's PagerAdapter changed the adapter's" + + " contents without calling PagerAdapter#notifyDataSetChanged!" + + " Expected adapter item count: " + mExpectedAdapterCount + ", found: " + N + + " Pager id: " + resName + + " Pager class: " + getClass() + + " Problematic adapter: " + mAdapter.getClass()); + } + + // Locate the currently focused item or add it if needed. + int curIndex = -1; + ItemInfo curItem = null; + for (curIndex = 0; curIndex < mItems.size(); curIndex++) { + final ItemInfo ii = mItems.get(curIndex); + if (ii.position >= mCurItem) { + if (ii.position == mCurItem) curItem = ii; + break; + } + } + + if (curItem == null && N > 0) { + curItem = addNewItem(mCurItem, curIndex); + } + + // Fill 3x the available width or up to the number of offscreen + // pages requested to either side, whichever is larger. + // If we have no current item we have no work to do. + if (curItem != null) { + float extraWidthLeft = 0.f; + int itemIndex = curIndex - 1; + ItemInfo ii = itemIndex >= 0 ? mItems.get(itemIndex) : null; + final int clientWidth = getClientWidth(); + final float leftWidthNeeded = clientWidth <= 0 ? 0 : + 2.f - curItem.widthFactor + (float) getPaddingLeft() / (float) clientWidth; + for (int pos = mCurItem - 1; pos >= 0; pos--) { + if (extraWidthLeft >= leftWidthNeeded && pos < startPos) { + if (ii == null) { + break; + } + if (pos == ii.position && !ii.scrolling) { + mItems.remove(itemIndex); + mAdapter.destroyItem(this, pos, ii.object); + if (DEBUG) { + Log.i(TAG, "populate() - destroyItem() with pos: " + pos + + " view: " + ((View) ii.object)); + } + itemIndex--; + curIndex--; + ii = itemIndex >= 0 ? mItems.get(itemIndex) : null; + } + } else if (ii != null && pos == ii.position) { + extraWidthLeft += ii.widthFactor; + itemIndex--; + ii = itemIndex >= 0 ? mItems.get(itemIndex) : null; + } else { + ii = addNewItem(pos, itemIndex + 1); + extraWidthLeft += ii.widthFactor; + curIndex++; + ii = itemIndex >= 0 ? mItems.get(itemIndex) : null; + } + } + + float extraWidthRight = curItem.widthFactor; + itemIndex = curIndex + 1; + if (extraWidthRight < 2.f) { + ii = itemIndex < mItems.size() ? mItems.get(itemIndex) : null; + final float rightWidthNeeded = clientWidth <= 0 ? 0 : + (float) getPaddingRight() / (float) clientWidth + 2.f; + for (int pos = mCurItem + 1; pos < N; pos++) { + if (extraWidthRight >= rightWidthNeeded && pos > endPos) { + if (ii == null) { + break; + } + if (pos == ii.position && !ii.scrolling) { + mItems.remove(itemIndex); + mAdapter.destroyItem(this, pos, ii.object); + if (DEBUG) { + Log.i(TAG, "populate() - destroyItem() with pos: " + pos + + " view: " + ((View) ii.object)); + } + ii = itemIndex < mItems.size() ? mItems.get(itemIndex) : null; + } + } else if (ii != null && pos == ii.position) { + extraWidthRight += ii.widthFactor; + itemIndex++; + ii = itemIndex < mItems.size() ? mItems.get(itemIndex) : null; + } else { + ii = addNewItem(pos, itemIndex); + itemIndex++; + extraWidthRight += ii.widthFactor; + ii = itemIndex < mItems.size() ? mItems.get(itemIndex) : null; + } + } + } + + calculatePageOffsets(curItem, curIndex, oldCurInfo); + } + + if (DEBUG) { + Log.i(TAG, "Current page list:"); + for (int i=0; i<mItems.size(); i++) { + Log.i(TAG, "#" + i + ": page " + mItems.get(i).position); + } + } + + mAdapter.setPrimaryItem(this, mCurItem, curItem != null ? curItem.object : null); + + mAdapter.finishUpdate(this); + + // Check width measurement of current pages and drawing sort order. + // Update LayoutParams as needed. + final int childCount = getChildCount(); + for (int i = 0; i < childCount; i++) { + final View child = getChildAt(i); + final LayoutParams lp = (LayoutParams) child.getLayoutParams(); + lp.childIndex = i; + if (!lp.isDecor) { + if (lp.widthFactor == 0.f) { + // 0 means requery the adapter for this, it doesn't have a valid width. + final ItemInfo ii = infoForChild(child); + if (ii != null) { + lp.widthFactor = ii.widthFactor; + lp.position = ii.position; + } + } + } + } + + updateViewOnClickListeners(); + updateViewOnLongClickListeners(); + + sortChildDrawingOrder(); + + if (hasFocus()) { + View currentFocused = findFocus(); + ItemInfo ii = currentFocused != null ? infoForAnyChild(currentFocused) : null; + if (ii == null || ii.position != mCurItem) { + for (int i=0; i<getChildCount(); i++) { + View child = getChildAt(i); + ii = infoForChild(child); + if (ii != null && ii.position == mCurItem) { + if (child.requestFocus(focusDirection)) { + break; + } + } + } + } + } + } + + private void sortChildDrawingOrder() { + if (mDrawingOrder != DRAW_ORDER_DEFAULT) { + if (mDrawingOrderedChildren == null) { + mDrawingOrderedChildren = new ArrayList<View>(); + } else { + mDrawingOrderedChildren.clear(); + } + final int childCount = getChildCount(); + for (int i = 0; i < childCount; i++) { + final View child = getChildAt(i); + mDrawingOrderedChildren.add(child); + } + Collections.sort(mDrawingOrderedChildren, mDrawOrderComparator); + } + } + + private void calculatePageOffsets(ItemInfo curItem, int curIndex, ItemInfo oldCurInfo) { + final int N = mAdapter.getCount(); + final int width = getClientWidth(); + final float marginOffset = width > 0 ? (float) mPageMargin / width : 0; + // Fix up offsets for later layout. + if (oldCurInfo != null) { + final int oldCurPosition = oldCurInfo.position; + // Base offsets off of oldCurInfo. + if (oldCurPosition < curItem.position) { + int itemIndex = 0; + ItemInfo ii = null; + float offset = oldCurInfo.offset + oldCurInfo.widthFactor + marginOffset; + for (int pos = oldCurPosition + 1; + pos <= curItem.position && itemIndex < mItems.size(); pos++) { + ii = mItems.get(itemIndex); + while (pos > ii.position && itemIndex < mItems.size() - 1) { + itemIndex++; + ii = mItems.get(itemIndex); + } + while (pos < ii.position) { + // We don't have an item populated for this, + // ask the adapter for an offset. + offset += mAdapter.getPageWidth(pos) + marginOffset; + pos++; + } + ii.offset = offset; + offset += ii.widthFactor + marginOffset; + } + } else if (oldCurPosition > curItem.position) { + int itemIndex = mItems.size() - 1; + ItemInfo ii = null; + float offset = oldCurInfo.offset; + for (int pos = oldCurPosition - 1; + pos >= curItem.position && itemIndex >= 0; pos--) { + ii = mItems.get(itemIndex); + while (pos < ii.position && itemIndex > 0) { + itemIndex--; + ii = mItems.get(itemIndex); + } + while (pos > ii.position) { + // We don't have an item populated for this, + // ask the adapter for an offset. + offset -= mAdapter.getPageWidth(pos) + marginOffset; + pos--; + } + offset -= ii.widthFactor + marginOffset; + ii.offset = offset; + } + } + } + + // Base all offsets off of curItem. + final int itemCount = mItems.size(); + float offset = curItem.offset; + int pos = curItem.position - 1; + mFirstOffset = curItem.position == 0 ? curItem.offset : -Float.MAX_VALUE; + + if (mOffsetToLastPageAllowed) { + mLastOffset = curItem.position == N - 1 ? curItem.offset : Float.MAX_VALUE; + } else { + mLastOffset = curItem.position == N - 1 ? + curItem.offset + curItem.widthFactor - 1 : Float.MAX_VALUE; + } + // Previous pages + for (int i = curIndex - 1; i >= 0; i--, pos--) { + final ItemInfo ii = mItems.get(i); + while (pos > ii.position) { + offset -= mAdapter.getPageWidth(pos--) + marginOffset; + } + offset -= ii.widthFactor + marginOffset; + ii.offset = offset; + if (ii.position == 0) mFirstOffset = offset; + } + offset = curItem.offset + curItem.widthFactor + marginOffset; + pos = curItem.position + 1; + // Next pages + for (int i = curIndex + 1; i < itemCount; i++, pos++) { + final ItemInfo ii = mItems.get(i); + while (pos < ii.position) { + offset += mAdapter.getPageWidth(pos++) + marginOffset; + } + if (ii.position == N - 1) { + mLastOffset = (mOffsetToLastPageAllowed) ? offset : + offset + curItem.widthFactor - 1; + } + ii.offset = offset; + offset += ii.widthFactor + marginOffset; + } + + mNeedCalculatePageOffsets = false; + } + + /** + * This is the persistent state that is saved by ViewPager. Only needed + * if you are creating a sublass of ViewPager that must save its own + * state, in which case it should implement a subclass of this which + * contains that state. + */ + public static class SavedState extends BaseSavedState { + int position; + Parcelable adapterState; + ClassLoader loader; + + public SavedState(Parcelable superState) { + super(superState); + } + + @Override + public void writeToParcel(Parcel out, int flags) { + super.writeToParcel(out, flags); + out.writeInt(position); + out.writeParcelable(adapterState, flags); + } + + @Override + public String toString() { + return "FragmentPager.SavedState{" + + Integer.toHexString(System.identityHashCode(this)) + + " position=" + position + "}"; + } + + public static final Parcelable.Creator<SavedState> CREATOR + = ParcelableCompat.newCreator(new ParcelableCompatCreatorCallbacks<SavedState>() { + @Override + public SavedState createFromParcel(Parcel in, ClassLoader loader) { + return new SavedState(in, loader); + } + + @Override + public SavedState[] newArray(int size) { + return new SavedState[size]; + } + }); + + SavedState(Parcel in, ClassLoader loader) { + super(in); + if (loader == null) { + loader = getClass().getClassLoader(); + } + position = in.readInt(); + adapterState = in.readParcelable(loader); + this.loader = loader; + } + } + + @Override + public Parcelable onSaveInstanceState() { + Parcelable superState = super.onSaveInstanceState(); + SavedState ss = new SavedState(superState); + ss.position = mCurItem; + if (mAdapter != null) { + ss.adapterState = mAdapter.saveState(); + } + return ss; + } + + @Override + public void onRestoreInstanceState(Parcelable state) { + if (!(state instanceof SavedState)) { + super.onRestoreInstanceState(state); + return; + } + + SavedState ss = (SavedState)state; + super.onRestoreInstanceState(ss.getSuperState()); + + if (mAdapter != null) { + mAdapter.restoreState(ss.adapterState, ss.loader); + setCurrentItemInternal(ss.position, false, true); + } else { + mRestoredCurItem = ss.position; + mRestoredAdapterState = ss.adapterState; + mRestoredClassLoader = ss.loader; + } + } + + @Override + public void addView(View child, int index, ViewGroup.LayoutParams params) { + if (!checkLayoutParams(params)) { + params = generateLayoutParams(params); + } + final LayoutParams lp = (LayoutParams) params; + lp.isDecor |= child instanceof Decor; + if (mInLayout) { + if (lp != null && lp.isDecor) { + throw new IllegalStateException("Cannot add pager decor view during layout"); + } + lp.needsMeasure = true; + addViewInLayout(child, index, params); + } else { + super.addView(child, index, params); + } + + if (USE_CACHE) { + if (child.getVisibility() != GONE) { + child.setDrawingCacheEnabled(mScrollingCacheEnabled); + } else { + child.setDrawingCacheEnabled(false); + } + } + } + + @Override + public void removeView(View view) { + if (mInLayout) { + removeViewInLayout(view); + } else { + super.removeView(view); + } + } + + ItemInfo infoForChild(View child) { + for (int i=0; i<mItems.size(); i++) { + ItemInfo ii = mItems.get(i); + if (mAdapter.isViewFromObject(child, ii.object)) { + return ii; + } + } + return null; + } + + ItemInfo infoForAnyChild(View child) { + ViewParent parent; + while ((parent=child.getParent()) != this) { + if (parent == null || !(parent instanceof View)) { + return null; + } + child = (View)parent; + } + return infoForChild(child); + } + + ItemInfo infoForPosition(int position) { + for (int i = 0; i < mItems.size(); i++) { + ItemInfo ii = mItems.get(i); + if (ii.position == position) { + return ii; + } + } + return null; + } + + @Override + protected void onAttachedToWindow() { + super.onAttachedToWindow(); + mFirstLayout = true; + } + + @Override + protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { + // For simple implementation, our internal size is always 0. + // We depend on the container to specify the layout size of + // our view. We can't really know what it is since we will be + // adding and removing different arbitrary views and do not + // want the layout to change as this happens. + setMeasuredDimension(getDefaultSize(0, widthMeasureSpec), + getDefaultSize(0, heightMeasureSpec)); + + final int measuredWidth = getMeasuredWidth(); + final int maxGutterSize = measuredWidth / 10; + mGutterSize = Math.min(maxGutterSize, mDefaultGutterSize); + + // Children are just made to fill our space. + int childWidthSize = measuredWidth - getPaddingLeft() - getPaddingRight(); + int childHeightSize = getMeasuredHeight() - getPaddingTop() - getPaddingBottom(); + + /* + * Make sure all children have been properly measured. Decor views first. + * Right now we cheat and make this less complicated by assuming decor + * views won't intersect. We will pin to edges based on gravity. + */ + int size = getChildCount(); + for (int i = 0; i < size; ++i) { + final View child = getChildAt(i); + if (child.getVisibility() != GONE) { + final LayoutParams lp = (LayoutParams) child.getLayoutParams(); + if (lp != null && lp.isDecor) { + final int hgrav = lp.gravity & Gravity.HORIZONTAL_GRAVITY_MASK; + final int vgrav = lp.gravity & Gravity.VERTICAL_GRAVITY_MASK; + int widthMode = MeasureSpec.AT_MOST; + int heightMode = MeasureSpec.AT_MOST; + boolean consumeVertical = vgrav == Gravity.TOP || vgrav == Gravity.BOTTOM; + boolean consumeHorizontal = hgrav == Gravity.LEFT || hgrav == Gravity.RIGHT; + + if (consumeVertical) { + widthMode = MeasureSpec.EXACTLY; + } else if (consumeHorizontal) { + heightMode = MeasureSpec.EXACTLY; + } + + int widthSize = childWidthSize; + int heightSize = childHeightSize; + if (lp.width != LayoutParams.WRAP_CONTENT) { + widthMode = MeasureSpec.EXACTLY; + if (lp.width != LayoutParams.FILL_PARENT) { + widthSize = lp.width; + } + } + if (lp.height != LayoutParams.WRAP_CONTENT) { + heightMode = MeasureSpec.EXACTLY; + if (lp.height != LayoutParams.FILL_PARENT) { + heightSize = lp.height; + } + } + final int widthSpec = MeasureSpec.makeMeasureSpec(widthSize, widthMode); + final int heightSpec = MeasureSpec.makeMeasureSpec(heightSize, heightMode); + child.measure(widthSpec, heightSpec); + + if (consumeVertical) { + childHeightSize -= child.getMeasuredHeight(); + } else if (consumeHorizontal) { + childWidthSize -= child.getMeasuredWidth(); + } + } + } + } + + mChildWidthMeasureSpec = MeasureSpec.makeMeasureSpec(childWidthSize, MeasureSpec.EXACTLY); + mChildHeightMeasureSpec = MeasureSpec.makeMeasureSpec(childHeightSize, MeasureSpec.EXACTLY); + + // Make sure we have created all fragments that we need to have shown. + mInLayout = true; + populate(); + mInLayout = false; + + // Page views next. + size = getChildCount(); + for (int i = 0; i < size; ++i) { + final View child = getChildAt(i); + if (child.getVisibility() != GONE) { + if (DEBUG) Log.v(TAG, "Measuring #" + i + " " + child + + ": " + mChildWidthMeasureSpec); + + final LayoutParams lp = (LayoutParams) child.getLayoutParams(); + if (lp == null || !lp.isDecor) { + final int widthSpec = MeasureSpec.makeMeasureSpec( + (int) (childWidthSize * lp.widthFactor), MeasureSpec.EXACTLY); + child.measure(widthSpec, mChildHeightMeasureSpec); + } + } + } + } + + @Override + protected void onSizeChanged(int w, int h, int oldw, int oldh) { + super.onSizeChanged(w, h, oldw, oldh); + + // Make sure scroll position is set correctly. + if (w != oldw) { + recomputeScrollPosition(w, oldw, mPageMargin, mPageMargin); + } + } + + // TODO: This is incorrect for flings... + private void recomputeScrollPosition(int width, int oldWidth, int margin, int oldMargin) { + if (oldWidth > 0 && !mItems.isEmpty()) { + final int widthWithMargin = width - getPaddingLeft() - getPaddingRight() + margin; + final int oldWidthWithMargin = oldWidth - getPaddingLeft() - getPaddingRight() + + oldMargin; + final int xpos = getScrollX(); + final float pageOffset = (float) xpos / oldWidthWithMargin; + final int newOffsetPixels = (int) (pageOffset * widthWithMargin); + + scrollTo(newOffsetPixels, getScrollY()); + if (!mScroller.isFinished()) { + // We now return to your regularly scheduled scroll, already in progress. + final int newDuration = Math.max(0, (int) (mScrollDuration - AnimationUtils.currentAnimationTimeMillis() - mScrollStartTime)); + ItemInfo targetInfo = infoForPosition(mCurItem); + + mScrollStartTime = AnimationUtils.currentAnimationTimeMillis(); + mScrollDuration = newDuration; + mScroller.startScroll(newOffsetPixels, 0, + (int) (targetInfo.offset * width), 0, newDuration); + } + } else { + final ItemInfo ii = infoForPosition(mCurItem); + final float scrollOffset = ii != null ? Math.min(ii.offset, mLastOffset) : 0; + final int scrollPos = (int) (scrollOffset * + (width - getPaddingLeft() - getPaddingRight())); + if (scrollPos != getScrollX()) { + completeScroll(false); + scrollTo(scrollPos, getScrollY()); + } + } + } + + @Override + protected void onLayout(boolean changed, int l, int t, int r, int b) { + final int count = getChildCount(); + int width = r - l; + int height = b - t; + int paddingLeft = getPaddingLeft(); + int paddingTop = getPaddingTop(); + int paddingRight = getPaddingRight(); + int paddingBottom = getPaddingBottom(); + final int scrollX = getScrollX(); + + int decorCount = 0; + + // First pass - decor views. We need to do this in two passes so that + // we have the proper offsets for non-decor views later. + for (int i = 0; i < count; i++) { + final View child = getChildAt(i); + if (child.getVisibility() != GONE) { + final LayoutParams lp = (LayoutParams) child.getLayoutParams(); + int childLeft = 0; + int childTop = 0; + if (lp.isDecor) { + final int hgrav = lp.gravity & Gravity.HORIZONTAL_GRAVITY_MASK; + final int vgrav = lp.gravity & Gravity.VERTICAL_GRAVITY_MASK; + switch (hgrav) { + default: + childLeft = paddingLeft; + break; + case Gravity.LEFT: + childLeft = paddingLeft; + paddingLeft += child.getMeasuredWidth(); + break; + case Gravity.CENTER_HORIZONTAL: + childLeft = Math.max((width - child.getMeasuredWidth()) / 2, + paddingLeft); + break; + case Gravity.RIGHT: + childLeft = width - paddingRight - child.getMeasuredWidth(); + paddingRight += child.getMeasuredWidth(); + break; + } + switch (vgrav) { + default: + childTop = paddingTop; + break; + case Gravity.TOP: + childTop = paddingTop; + paddingTop += child.getMeasuredHeight(); + break; + case Gravity.CENTER_VERTICAL: + childTop = Math.max((height - child.getMeasuredHeight()) / 2, + paddingTop); + break; + case Gravity.BOTTOM: + childTop = height - paddingBottom - child.getMeasuredHeight(); + paddingBottom += child.getMeasuredHeight(); + break; + } + childLeft += scrollX; + child.layout(childLeft, childTop, + childLeft + child.getMeasuredWidth(), + childTop + child.getMeasuredHeight()); + decorCount++; + } + } + } + + final int childWidth = width - paddingLeft - paddingRight; + // Page views. Do this once we have the right padding offsets from above. + for (int i = 0; i < count; i++) { + final View child = getChildAt(i); + if (child.getVisibility() != GONE) { + final LayoutParams lp = (LayoutParams) child.getLayoutParams(); + ItemInfo ii; + if (!lp.isDecor && (ii = infoForChild(child)) != null) { + int loff = (int) (childWidth * ii.offset); + int childLeft = paddingLeft + loff; + int childTop = paddingTop; + if (lp.needsMeasure) { + // This was added during layout and needs measurement. + // Do it now that we know what we're working with. + lp.needsMeasure = false; + final int widthSpec = MeasureSpec.makeMeasureSpec( + (int) (childWidth * lp.widthFactor), + MeasureSpec.EXACTLY); + final int heightSpec = MeasureSpec.makeMeasureSpec( + (int) (height - paddingTop - paddingBottom), + MeasureSpec.EXACTLY); + child.measure(widthSpec, heightSpec); + } + if (DEBUG) Log.v(TAG, "Positioning #" + i + " " + child + " f=" + ii.object + + ":" + childLeft + "," + childTop + " " + child.getMeasuredWidth() + + "x" + child.getMeasuredHeight()); + child.layout(childLeft, childTop, + childLeft + child.getMeasuredWidth(), + childTop + child.getMeasuredHeight()); + } + } + } + mTopPageBounds = paddingTop; + mBottomPageBounds = height - paddingBottom; + mDecorChildCount = decorCount; + + if (mFirstLayout) { + scrollToItem(mCurItem, false, 0, false); + } + + sortChildDrawingOrder(); + + mFirstLayout = false; + } + + private int constrainScroll(int x) { + int width = getClientWidth(); + + int firstOffset = (int) (mFirstOffset * width); + if (x < firstOffset) { + if (ViewCompat.getOverScrollMode(this) != OVER_SCROLL_NEVER && mLeftEdge.isFinished()) { + mLeftEdge.onAbsorb((int) Math.abs(mScroller.getCurrVelocity())); + } + + mFlinging = FLINGING_STOPPED; + mScroller.startScroll(firstOffset, 0, 0, 0); + mScroller.abortAnimation(); + return firstOffset; + } + + int lastOffset = (int) (mLastOffset * width); + if (x > lastOffset) { + if (ViewCompat.getOverScrollMode(this) != OVER_SCROLL_NEVER && mRightEdge.isFinished()) { + mRightEdge.onAbsorb((int) Math.abs(mScroller.getCurrVelocity())); + } + + mFlinging = FLINGING_STOPPED; + mScroller.startScroll(lastOffset, 0, 0, 0); + mScroller.abortAnimation(); + return lastOffset; + } + + + if (mFlinging != FLINGING_STOPPED) { + int finalX = mScroller.getFinalX(); + ItemInfo snapItemInfo = infoForScrollPosition(finalX); + int snapItemWidth = (int) (snapItemInfo.widthFactor * width); + int snapItemOffset = (int) (snapItemInfo.offset * width); + + // infoForScrollPosition() returns the closest item. However, we can only snap when we + // have the ItemInfo that finalX is inside of. + if (finalX > snapItemOffset && finalX < snapItemOffset + snapItemWidth) { + // If finalX was in the right half of the snap item, then we want to snap to the + // next item along. + if (finalX - snapItemOffset > snapItemWidth / 2) { + snapItemOffset += snapItemWidth; + } + + if (mFlinging == FLINGING_RIGHT) { + if (finalX > snapItemOffset) { + // Overscroll + if (x > snapItemOffset) { + mFlinging = FLINGING_STOPPED; + int overscroll = finalX - snapItemOffset; + mScroller.notifyHorizontalEdgeReached(x, snapItemOffset, overscroll); + } + } else { + // Underscroll + if (x > snapItemOffset - snapItemWidth) { + mFlinging = FLINGING_STOPPED; + mScroller.notifyFinalXExtended(snapItemOffset); + } + } + } else if (mFlinging == FLINGING_LEFT) { + if (finalX < snapItemOffset) { + // Overscroll + if (x < snapItemOffset) { + mFlinging = FLINGING_STOPPED; + int overscroll = snapItemOffset - finalX; + mScroller.notifyHorizontalEdgeReached(x, snapItemOffset, overscroll); + } + } else { + // Underscroll + if (x < snapItemOffset + snapItemWidth) { + mFlinging = FLINGING_STOPPED; + mScroller.notifyFinalXExtended(snapItemOffset); + } + } + + } + } + } + + return x; + } + + @Override + public void computeScroll() { + if (!mScroller.isFinished() && mScroller.computeScrollOffset()) { + int oldX = getScrollX(); + int oldY = getScrollY(); + int x = mScroller.getCurrX(); + int y = mScroller.getCurrY(); + + if (oldX != x || oldY != y) { + final ItemInfo ii = infoForScrollPosition(x); + populate(ii.position); + + x = constrainScroll(x); + scrollTo(x, y); + + if (!pageScrolled(x)) { + mScroller.abortAnimation(); + scrollTo(0, y); + } + } + + // Keep on drawing until the animation has finished. + ViewCompat.postInvalidateOnAnimation(this); + return; + } + + // Done with scroll, clean up state. + completeScroll(true); + } + + private boolean pageScrolled(int xpos) { + if (mItems.size() == 0) { + mCalledSuper = false; + onPageScrolled(0, 0, 0); + if (!mCalledSuper) { + throw new IllegalStateException( + "onPageScrolled did not call superclass implementation"); + } + return false; + } + final ItemInfo ii = infoForCurrentScrollPosition(); + final int width = getClientWidth(); + final int widthWithMargin = width + mPageMargin; + final float marginOffset = (float) mPageMargin / width; + final int currentPage = ii.position; + final float pageOffset = (((float) xpos / width) - ii.offset) / + (ii.widthFactor + marginOffset); + final int offsetPixels = (int) (pageOffset * widthWithMargin); + + mCalledSuper = false; + onPageScrolled(currentPage, pageOffset, offsetPixels); + if (!mCalledSuper) { + throw new IllegalStateException( + "onPageScrolled did not call superclass implementation"); + } + return true; + } + + private void transformPages() { + if (mPageTransformer != null) { + final int scrollX = getScrollX(); + final int childCount = getChildCount(); + for (int i = 0; i < childCount; i++) { + final View child = getChildAt(i); + final LayoutParams lp = (LayoutParams) child.getLayoutParams(); + + if (lp.isDecor) continue; + + final float transformPos = (float) (child.getLeft() - scrollX) / getClientWidth(); + mPageTransformer.transformPage(child, transformPos); + } + } + } + + /** + * This method will be invoked when the current page is scrolled, either as part + * of a programmatically initiated smooth scroll or a user initiated touch scroll. + * If you override this method you must call through to the superclass implementation + * (e.g. super.onPageScrolled(position, offset, offsetPixels)) before onPageScrolled + * returns. + * + * @param position Position index of the first page currently being displayed. + * Page position+1 will be visible if positionOffset is nonzero. + * @param offset Value from [0, 1) indicating the offset from the page at position. + * @param offsetPixels Value in pixels indicating the offset from position. + */ + protected void onPageScrolled(int position, float offset, int offsetPixels) { + // Offset any decor views if needed - keep them on-screen at all times. + if (mDecorChildCount > 0) { + final int scrollX = getScrollX(); + int paddingLeft = getPaddingLeft(); + int paddingRight = getPaddingRight(); + final int width = getWidth(); + final int childCount = getChildCount(); + for (int i = 0; i < childCount; i++) { + final View child = getChildAt(i); + final LayoutParams lp = (LayoutParams) child.getLayoutParams(); + if (!lp.isDecor) continue; + + final int hgrav = lp.gravity & Gravity.HORIZONTAL_GRAVITY_MASK; + int childLeft = 0; + switch (hgrav) { + default: + childLeft = paddingLeft; + break; + case Gravity.LEFT: + childLeft = paddingLeft; + paddingLeft += child.getWidth(); + break; + case Gravity.CENTER_HORIZONTAL: + childLeft = Math.max((width - child.getMeasuredWidth()) / 2, + paddingLeft); + break; + case Gravity.RIGHT: + childLeft = width - paddingRight - child.getMeasuredWidth(); + paddingRight += child.getMeasuredWidth(); + break; + } + childLeft += scrollX; + + final int childOffset = childLeft - child.getLeft(); + if (childOffset != 0) { + child.offsetLeftAndRight(childOffset); + } + } + } + + if (mOnPageChangeListener != null) { + mOnPageChangeListener.onPageScrolled(position, offset, offsetPixels); + } + if (mInternalPageChangeListener != null) { + mInternalPageChangeListener.onPageScrolled(position, offset, offsetPixels); + } + + transformPages(); + + mCalledSuper = true; + } + + private void completeScroll(boolean postEvents) { + boolean needPopulate = mScrollState == SCROLL_STATE_SETTLING; + if (needPopulate) { + // Done with scroll, no longer want to cache view drawing. + setScrollingCacheEnabled(false); + mScroller.abortAnimation(); + int oldX = getScrollX(); + int oldY = getScrollY(); + int x = mScroller.getCurrX(); + int y = mScroller.getCurrY(); + if (oldX != x || oldY != y) { + scrollTo(x, y); + } + } + for (int i=0; i<mItems.size(); i++) { + ItemInfo ii = mItems.get(i); + if (ii.scrolling) { + needPopulate = true; + ii.scrolling = false; + } + } + if (needPopulate) { + if (postEvents) { + ViewCompat.postOnAnimation(this, mEndScrollRunnable); + } else { + mEndScrollRunnable.run(); + } + } + } + + private boolean isGutterDrag(float x, float dx) { + return (x < mGutterSize && dx > 0) || (x > getWidth() - mGutterSize && dx < 0); + } + + private void enableLayers(boolean enable) { + final int childCount = getChildCount(); + for (int i = 0; i < childCount; i++) { + final int layerType = enable ? + ViewCompat.LAYER_TYPE_HARDWARE : ViewCompat.LAYER_TYPE_NONE; + ViewCompat.setLayerType(getChildAt(i), layerType, null); + } + } + + @Override + public boolean onInterceptTouchEvent(MotionEvent ev) { + /* + * This method JUST determines whether we want to intercept the motion. + * If we return true, onMotionEvent will be called and we do the actual + * scrolling there. + */ + + final int action = ev.getAction() & MotionEventCompat.ACTION_MASK; + + // Always take care of the touch gesture being complete. + if (action == MotionEvent.ACTION_CANCEL || action == MotionEvent.ACTION_UP) { + // Release the drag. + if (DEBUG) Log.v(TAG, "Intercept done!"); + mIsBeingDragged = false; + mIsUnableToDrag = false; + mActivePointerId = INVALID_POINTER; + if (mVelocityTracker != null) { + mVelocityTracker.recycle(); + mVelocityTracker = null; + } + return false; + } + + // Nothing more to do here if we have decided whether or not we + // are dragging. + if (action != MotionEvent.ACTION_DOWN) { + if (mIsBeingDragged) { + if (DEBUG) Log.v(TAG, "Intercept returning true!"); + return true; + } + if (mIsUnableToDrag) { + if (DEBUG) Log.v(TAG, "Intercept returning false!"); + return false; + } + } + + switch (action) { + case MotionEvent.ACTION_MOVE: { + /* + * mIsBeingDragged == false, otherwise the shortcut would have caught it. Check + * whether the user has moved far enough from his original down touch. + */ + + /* + * Locally do absolute value. mLastMotionY is set to the y value + * of the down event. + */ + final int activePointerId = mActivePointerId; + if (activePointerId == INVALID_POINTER) { + // If we don't have a valid id, the touch down wasn't on content. + break; + } + + final int pointerIndex = MotionEventCompat.findPointerIndex(ev, activePointerId); + final float x = MotionEventCompat.getX(ev, pointerIndex); + final float dx = x - mLastMotionX; + final float xDiff = Math.abs(dx); + final float y = MotionEventCompat.getY(ev, pointerIndex); + final float yDiff = Math.abs(y - mInitialMotionY); + if (DEBUG) Log.v(TAG, "Moved x to " + x + "," + y + " diff=" + xDiff + "," + yDiff); + + if (dx != 0 && !isGutterDrag(mLastMotionX, dx) && + canScroll(this, false, (int) dx, (int) x, (int) y)) { + // Nested view has scrollable area under this point. Let it be handled there. + mLastMotionX = x; + mLastMotionY = y; + mIsUnableToDrag = true; + return false; + } + if (xDiff > mTouchSlop && xDiff * 0.5f > yDiff) { + if (DEBUG) Log.v(TAG, "Starting drag!"); + mIsBeingDragged = true; + requestParentDisallowInterceptTouchEvent(true); + setScrollState(SCROLL_STATE_DRAGGING); + mLastMotionX = dx > 0 ? mInitialMotionX + mTouchSlop : + mInitialMotionX - mTouchSlop; + mLastMotionY = y; + setScrollingCacheEnabled(true); + } else if (yDiff > mTouchSlop) { + // The finger has moved enough in the vertical + // direction to be counted as a drag... abort + // any attempt to drag horizontally, to work correctly + // with children that have scrolling containers. + if (DEBUG) Log.v(TAG, "Starting unable to drag!"); + mIsUnableToDrag = true; + } + if (mIsBeingDragged) { + // Scroll to follow the motion event + if (performDrag(x)) { + ViewCompat.postInvalidateOnAnimation(this); + } + } + break; + } + + case MotionEvent.ACTION_DOWN: { + /* + * Remember location of down touch. + * ACTION_DOWN always refers to pointer index 0. + */ + mLastMotionX = mInitialMotionX = ev.getX(); + mLastMotionY = mInitialMotionY = ev.getY(); + mActivePointerId = MotionEventCompat.getPointerId(ev, 0); + mIsUnableToDrag = false; + + mScroller.computeScrollOffset(); + if (mScrollState == SCROLL_STATE_SETTLING && + Math.abs(mScroller.getFinalX() - mScroller.getCurrX()) > mCloseEnough) { + // Let the user 'catch' the pager as it animates. + mScroller.abortAnimation(); + populate(); + mIsBeingDragged = true; + requestParentDisallowInterceptTouchEvent(true); + setScrollState(SCROLL_STATE_DRAGGING); + } else { + completeScroll(false); + mIsBeingDragged = false; + } + + if (DEBUG) Log.v(TAG, "Down at " + mLastMotionX + "," + mLastMotionY + + " mIsBeingDragged=" + mIsBeingDragged + + "mIsUnableToDrag=" + mIsUnableToDrag); + break; + } + + case MotionEventCompat.ACTION_POINTER_UP: + onSecondaryPointerUp(ev); + break; + } + + if (mVelocityTracker == null) { + mVelocityTracker = VelocityTracker.obtain(); + } + mVelocityTracker.addMovement(ev); + + /* + * The only time we want to intercept motion events is if we are in the + * drag mode. + */ + return mIsBeingDragged; + } + + @Override + public boolean onTouchEvent(MotionEvent ev) { + if (mFakeDragging) { + // A fake drag is in progress already, ignore this real one + // but still eat the touch events. + // (It is likely that the user is multi-touching the screen.) + return true; + } + + if (ev.getAction() == MotionEvent.ACTION_DOWN && ev.getEdgeFlags() != 0) { + // Don't handle edge touches immediately -- they may actually belong to one of our + // descendants. + return false; + } + + if (mAdapter == null || mAdapter.getCount() == 0) { + // Nothing to present or scroll; nothing to touch. + return false; + } + + if (mVelocityTracker == null) { + mVelocityTracker = VelocityTracker.obtain(); + } + mVelocityTracker.addMovement(ev); + + final int action = ev.getAction(); + boolean needsInvalidate = false; + + switch (action & MotionEventCompat.ACTION_MASK) { + case MotionEvent.ACTION_DOWN: { + mScroller.abortAnimation(); + populate(); + + // Remember where the motion event started + mLastMotionX = mInitialMotionX = ev.getX(); + mLastMotionY = mInitialMotionY = ev.getY(); + mActivePointerId = MotionEventCompat.getPointerId(ev, 0); + break; + } + case MotionEvent.ACTION_MOVE: + if (!mIsBeingDragged) { + final int pointerIndex = MotionEventCompat.findPointerIndex(ev, mActivePointerId); + final float x = MotionEventCompat.getX(ev, pointerIndex); + final float xDiff = Math.abs(x - mLastMotionX); + final float y = MotionEventCompat.getY(ev, pointerIndex); + final float yDiff = Math.abs(y - mLastMotionY); + if (DEBUG) Log.v(TAG, "Moved x to " + x + "," + y + " diff=" + xDiff + "," + yDiff); + if (xDiff > mTouchSlop && xDiff > yDiff) { + if (DEBUG) Log.v(TAG, "Starting drag!"); + mIsBeingDragged = true; + requestParentDisallowInterceptTouchEvent(true); + mLastMotionX = x - mInitialMotionX > 0 ? mInitialMotionX + mTouchSlop : + mInitialMotionX - mTouchSlop; + mLastMotionY = y; + setScrollState(SCROLL_STATE_DRAGGING); + setScrollingCacheEnabled(true); + + // Disallow Parent Intercept, just in case + ViewParent parent = getParent(); + if (parent != null) { + parent.requestDisallowInterceptTouchEvent(true); + } + } + } + // Not else! Note that mIsBeingDragged can be set above. + if (mIsBeingDragged) { + // Scroll to follow the motion event + final int activePointerIndex = MotionEventCompat.findPointerIndex( + ev, mActivePointerId); + final float x = MotionEventCompat.getX(ev, activePointerIndex); + needsInvalidate |= performDrag(x); + } + break; + case MotionEvent.ACTION_UP: + if (mIsBeingDragged) { + final VelocityTracker velocityTracker = mVelocityTracker; + velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity); + int initialVelocity = (int) VelocityTrackerCompat.getXVelocity( + velocityTracker, mActivePointerId); + final int width = getClientWidth(); + final int scrollX = getScrollX(); + final ItemInfo ii = infoForCurrentScrollPosition(); + final int currentPage = ii.position; + final float pageOffset = (((float) scrollX / width) - ii.offset) / ii.widthFactor; + final int activePointerIndex = + MotionEventCompat.findPointerIndex(ev, mActivePointerId); + final float x = MotionEventCompat.getX(ev, activePointerIndex); + final int totalDelta = (int) (x - mInitialMotionX); + + if (Math.abs(initialVelocity) > mMinimumVelocity) { + fling(initialVelocity); + ViewCompat.postInvalidateOnAnimation(this); + } else { + int nextPage = determineTargetPage(currentPage, pageOffset, initialVelocity, + totalDelta); + setCurrentItemInternal(nextPage, true, true, initialVelocity); + needsInvalidate = mLeftEdge.onRelease() | mRightEdge.onRelease(); + } + + mActivePointerId = INVALID_POINTER; + endDrag(); + } else { + + } + break; + case MotionEvent.ACTION_CANCEL: + if (mIsBeingDragged) { + scrollToItem(mCurItem, true, 0, false); + mActivePointerId = INVALID_POINTER; + endDrag(); + needsInvalidate = mLeftEdge.onRelease() | mRightEdge.onRelease(); + } + break; + case MotionEventCompat.ACTION_POINTER_DOWN: { + final int index = MotionEventCompat.getActionIndex(ev); + final float x = MotionEventCompat.getX(ev, index); + mLastMotionX = x; + mActivePointerId = MotionEventCompat.getPointerId(ev, index); + break; + } + case MotionEventCompat.ACTION_POINTER_UP: + onSecondaryPointerUp(ev); + mLastMotionX = MotionEventCompat.getX(ev, + MotionEventCompat.findPointerIndex(ev, mActivePointerId)); + break; + } + if (needsInvalidate) { + ViewCompat.postInvalidateOnAnimation(this); + } + return true; + } + + private void requestParentDisallowInterceptTouchEvent(boolean disallowIntercept) { + final ViewParent parent = getParent(); + if (parent != null) { + parent.requestDisallowInterceptTouchEvent(disallowIntercept); + } + } + + private boolean performDrag(float x) { + boolean needsInvalidate = false; + + final float deltaX = mLastMotionX - x; + mLastMotionX = x; + + float oldScrollX = getScrollX(); + float scrollX = oldScrollX + deltaX; + final int width = getClientWidth(); + + float leftBound = width * mFirstOffset; + float rightBound = width * mLastOffset; + boolean leftAbsolute = true; + boolean rightAbsolute = true; + + final ItemInfo firstItem = mItems.get(0); + final ItemInfo lastItem = mItems.get(mItems.size() - 1); + if (firstItem.position != 0) { + leftAbsolute = false; + leftBound = firstItem.offset * width; + } + if (lastItem.position != mAdapter.getCount() - 1) { + rightAbsolute = false; + rightBound = lastItem.offset * width; + } + + if (scrollX < leftBound) { + if (ViewCompat.getOverScrollMode(this) != OVER_SCROLL_NEVER && leftAbsolute) { + float over = leftBound - scrollX; + needsInvalidate = mLeftEdge.onPull(Math.abs(over) / width); + } + scrollX = leftBound; + } else if (scrollX > rightBound) { + if (ViewCompat.getOverScrollMode(this) != OVER_SCROLL_NEVER && rightAbsolute) { + float over = scrollX - rightBound; + needsInvalidate = mRightEdge.onPull(Math.abs(over) / width); + } + scrollX = rightBound; + } + + // Don't lose the rounded component + mLastMotionX += scrollX - (int) scrollX; + scrollTo((int) scrollX, getScrollY()); + pageScrolled((int) scrollX); + + final ItemInfo ii = infoForCurrentScrollPosition(); + populate(ii.position); + + return needsInvalidate; + } + + /** + * + * @param x scroll position + * @return Info about the page at the specified scroll position. + * This can be synthetic for a missing middle page; the 'object' field can be null. + */ + private ItemInfo infoForScrollPosition(int x) { + final int width = getClientWidth(); + final float scrollOffset = width > 0 ? (float) x / width : 0; + final float marginOffset = width > 0 ? (float) mPageMargin / width : 0; + int lastPos = -1; + float lastOffset = 0.f; + float lastWidth = 0.f; + boolean first = true; + + ItemInfo lastItem = null; + for (int i = 0; i < mItems.size(); i++) { + ItemInfo ii = mItems.get(i); + float offset; + if (!first && ii.position != lastPos + 1) { + // Create a synthetic item for a missing page. + ii = mTempItem; + ii.offset = lastOffset + lastWidth + marginOffset; + ii.position = lastPos + 1; + ii.widthFactor = mAdapter.getPageWidth(ii.position); + i--; + } + offset = ii.offset; + + final float leftBound = offset; + final float rightBound = offset + ii.widthFactor + marginOffset; + if (first || scrollOffset >= leftBound) { + if (scrollOffset < rightBound || i == mItems.size() - 1) { + return ii; + } + } else { + return lastItem; + } + first = false; + lastPos = ii.position; + lastOffset = offset; + lastWidth = ii.widthFactor; + lastItem = ii; + } + + return lastItem; + } + + /** + * @return Info about the page at the current scroll position. + * This can be synthetic for a missing middle page; the 'object' field can be null. + */ + private ItemInfo infoForCurrentScrollPosition() { + return infoForScrollPosition(getScrollX()); + } + + private int determineTargetPage(int currentPage, float pageOffset, int velocity, int deltaX) { + int targetPage; + if (Math.abs(deltaX) > mFlingDistance && Math.abs(velocity) > mMinimumVelocity) { + targetPage = velocity > 0 ? currentPage : currentPage + 1; + } else { + final float truncator = currentPage >= mCurItem ? 0.4f : 0.6f; + targetPage = (int) (currentPage + pageOffset + truncator); + } + + if (mItems.size() > 0) { + final ItemInfo firstItem = mItems.get(0); + final ItemInfo lastItem = mItems.get(mItems.size() - 1); + + // Only let the user target pages we have items for + targetPage = Math.max(firstItem.position, Math.min(targetPage, lastItem.position)); + } + + return targetPage; + } + + private void fling(int velocity) { + final int sx = getScrollX(); + final int sy = getScrollY(); + + mScroller.fling(sx, sy, -velocity, 0, Integer.MIN_VALUE, Integer.MAX_VALUE, sy, sy); + mFlinging = (velocity > 0) ? FLINGING_LEFT : FLINGING_RIGHT; + + setScrollState(SCROLL_STATE_SETTLING); + } + + @Override + public void draw(Canvas canvas) { + super.draw(canvas); + boolean needsInvalidate = false; + + final int overScrollMode = ViewCompat.getOverScrollMode(this); + if (overScrollMode == ViewCompat.OVER_SCROLL_ALWAYS || + (overScrollMode == ViewCompat.OVER_SCROLL_IF_CONTENT_SCROLLS && + mAdapter != null && mAdapter.getCount() > 1)) { + if (!mLeftEdge.isFinished()) { + final int restoreCount = canvas.save(); + final int height = getHeight() - getPaddingTop() - getPaddingBottom(); + final int width = getWidth(); + + canvas.rotate(270); + canvas.translate(-height + getPaddingTop(), mFirstOffset * width); + mLeftEdge.setSize(height, width); + needsInvalidate |= mLeftEdge.draw(canvas); + canvas.restoreToCount(restoreCount); + } + if (!mRightEdge.isFinished()) { + final int restoreCount = canvas.save(); + final int width = getWidth(); + final int height = getHeight() - getPaddingTop() - getPaddingBottom(); + + canvas.rotate(90); + canvas.translate(-getPaddingTop(), -(mLastOffset + 1) * width); + mRightEdge.setSize(height, width); + needsInvalidate |= mRightEdge.draw(canvas); + canvas.restoreToCount(restoreCount); + } + } else { + mLeftEdge.finish(); + mRightEdge.finish(); + } + + if (needsInvalidate) { + // Keep animating + ViewCompat.postInvalidateOnAnimation(this); + } + } + + @Override + protected void onDraw(Canvas canvas) { + super.onDraw(canvas); + + // Draw the margin drawable between pages if needed. + if (mPageMargin > 0 && mMarginDrawable != null && mItems.size() > 0 && mAdapter != null) { + final int scrollX = getScrollX(); + final int width = getWidth(); + + final float marginOffset = (float) mPageMargin / width; + int itemIndex = 0; + ItemInfo ii = mItems.get(0); + float offset = ii.offset; + final int itemCount = mItems.size(); + final int firstPos = ii.position; + final int lastPos = mItems.get(itemCount - 1).position; + for (int pos = firstPos; pos < lastPos; pos++) { + while (pos > ii.position && itemIndex < itemCount) { + ii = mItems.get(++itemIndex); + } + + float drawAt; + if (pos == ii.position) { + drawAt = (ii.offset + ii.widthFactor) * width; + offset = ii.offset + ii.widthFactor + marginOffset; + } else { + float widthFactor = mAdapter.getPageWidth(pos); + drawAt = (offset + widthFactor) * width; + offset += widthFactor + marginOffset; + } + + if (drawAt + mPageMargin > scrollX) { + mMarginDrawable.setBounds((int) drawAt, mTopPageBounds, + (int) (drawAt + mPageMargin + 0.5f), mBottomPageBounds); + mMarginDrawable.draw(canvas); + } + + if (drawAt > scrollX + width) { + break; // No more visible, no sense in continuing + } + } + } + } + + /** + * Start a fake drag of the pager. + * + * <p>A fake drag can be useful if you want to synchronize the motion of the ViewPager + * with the touch scrolling of another view, while still letting the ViewPager + * control the snapping motion and fling behavior. (e.g. parallax-scrolling tabs.) + * Call {@link #fakeDragBy(float)} to simulate the actual drag motion. Call + * {@link #endFakeDrag()} to complete the fake drag and fling as necessary. + * + * <p>During a fake drag the ViewPager will ignore all touch events. If a real drag + * is already in progress, this method will return false. + * + * @return true if the fake drag began successfully, false if it could not be started. + * + * @see #fakeDragBy(float) + * @see #endFakeDrag() + */ + public boolean beginFakeDrag() { + if (mIsBeingDragged) { + return false; + } + mFakeDragging = true; + setScrollState(SCROLL_STATE_DRAGGING); + mInitialMotionX = mLastMotionX = 0; + if (mVelocityTracker == null) { + mVelocityTracker = VelocityTracker.obtain(); + } else { + mVelocityTracker.clear(); + } + final long time = SystemClock.uptimeMillis(); + final MotionEvent ev = MotionEvent.obtain(time, time, MotionEvent.ACTION_DOWN, 0, 0, 0); + mVelocityTracker.addMovement(ev); + ev.recycle(); + mFakeDragBeginTime = time; + return true; + } + + /** + * End a fake drag of the pager. + * + * @see #beginFakeDrag() + * @see #fakeDragBy(float) + */ + public void endFakeDrag() { + if (!mFakeDragging) { + throw new IllegalStateException("No fake drag in progress. Call beginFakeDrag first."); + } + + final VelocityTracker velocityTracker = mVelocityTracker; + velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity); + int initialVelocity = (int) VelocityTrackerCompat.getXVelocity( + velocityTracker, mActivePointerId); + final int width = getClientWidth(); + final int scrollX = getScrollX(); + final ItemInfo ii = infoForCurrentScrollPosition(); + final int currentPage = ii.position; + final float pageOffset = (((float) scrollX / width) - ii.offset) / ii.widthFactor; + final int totalDelta = (int) (mLastMotionX - mInitialMotionX); + int nextPage = determineTargetPage(currentPage, pageOffset, initialVelocity, + totalDelta); + setCurrentItemInternal(nextPage, true, true, initialVelocity); + endDrag(); + + mFakeDragging = false; + } + + /** + * Fake drag by an offset in pixels. You must have called {@link #beginFakeDrag()} first. + * + * @param xOffset Offset in pixels to drag by. + * @see #beginFakeDrag() + * @see #endFakeDrag() + */ + public void fakeDragBy(float xOffset) { + if (!mFakeDragging) { + throw new IllegalStateException("No fake drag in progress. Call beginFakeDrag first."); + } + + mLastMotionX += xOffset; + + float oldScrollX = getScrollX(); + float scrollX = oldScrollX - xOffset; + final int width = getClientWidth(); + + float leftBound = width * mFirstOffset; + float rightBound = width * mLastOffset; + + final ItemInfo firstItem = mItems.get(0); + final ItemInfo lastItem = mItems.get(mItems.size() - 1); + if (firstItem.position != 0) { + leftBound = firstItem.offset * width; + } + if (lastItem.position != mAdapter.getCount() - 1) { + rightBound = lastItem.offset * width; + } + + if (scrollX < leftBound) { + scrollX = leftBound; + } else if (scrollX > rightBound) { + scrollX = rightBound; + } + // Don't lose the rounded component + mLastMotionX += scrollX - (int) scrollX; + scrollTo((int) scrollX, getScrollY()); + pageScrolled((int) scrollX); + + // Synthesize an event for the VelocityTracker. + final long time = SystemClock.uptimeMillis(); + final MotionEvent ev = MotionEvent.obtain(mFakeDragBeginTime, time, MotionEvent.ACTION_MOVE, + mLastMotionX, 0, 0); + mVelocityTracker.addMovement(ev); + ev.recycle(); + } + + /** + * Returns true if a fake drag is in progress. + * + * @return true if currently in a fake drag, false otherwise. + * + * @see #beginFakeDrag() + * @see #fakeDragBy(float) + * @see #endFakeDrag() + */ + public boolean isFakeDragging() { + return mFakeDragging; + } + + private void onSecondaryPointerUp(MotionEvent ev) { + final int pointerIndex = MotionEventCompat.getActionIndex(ev); + final int pointerId = MotionEventCompat.getPointerId(ev, pointerIndex); + if (pointerId == mActivePointerId) { + // This was our active pointer going up. Choose a new + // active pointer and adjust accordingly. + final int newPointerIndex = pointerIndex == 0 ? 1 : 0; + mLastMotionX = MotionEventCompat.getX(ev, newPointerIndex); + mActivePointerId = MotionEventCompat.getPointerId(ev, newPointerIndex); + if (mVelocityTracker != null) { + mVelocityTracker.clear(); + } + } + } + + private void endDrag() { + mIsBeingDragged = false; + mIsUnableToDrag = false; + + if (mVelocityTracker != null) { + mVelocityTracker.recycle(); + mVelocityTracker = null; + } + } + + private void setScrollingCacheEnabled(boolean enabled) { + if (mScrollingCacheEnabled != enabled) { + mScrollingCacheEnabled = enabled; + if (USE_CACHE) { + final int size = getChildCount(); + for (int i = 0; i < size; ++i) { + final View child = getChildAt(i); + if (child.getVisibility() != GONE) { + child.setDrawingCacheEnabled(enabled); + } + } + } + } + } + + public boolean canScrollHorizontally(int direction) { + if (mAdapter == null) { + return false; + } + + final int width = getClientWidth(); + final int scrollX = getScrollX(); + if (direction < 0) { + return (scrollX > (int) (width * mFirstOffset)); + } else if (direction > 0) { + return (scrollX < (int) (width * mLastOffset)); + } else { + return false; + } + } + + /** + * Tests scrollability within child views of v given a delta of dx. + * + * @param v View to test for horizontal scrollability + * @param checkV Whether the view v passed should itself be checked for scrollability (true), + * or just its children (false). + * @param dx Delta scrolled in pixels + * @param x X coordinate of the active touch point + * @param y Y coordinate of the active touch point + * @return true if child views of v can be scrolled by delta of dx. + */ + protected boolean canScroll(View v, boolean checkV, int dx, int x, int y) { + if (v instanceof ViewGroup) { + final ViewGroup group = (ViewGroup) v; + final int scrollX = v.getScrollX(); + final int scrollY = v.getScrollY(); + final int count = group.getChildCount(); + // Count backwards - let topmost views consume scroll distance first. + for (int i = count - 1; i >= 0; i--) { + // TODO: Add versioned support here for transformed views. + // This will not work for transformed views in Honeycomb+ + final View child = group.getChildAt(i); + if (x + scrollX >= child.getLeft() && x + scrollX < child.getRight() && + y + scrollY >= child.getTop() && y + scrollY < child.getBottom() && + canScroll(child, true, dx, x + scrollX - child.getLeft(), + y + scrollY - child.getTop())) { + return true; + } + } + } + + return checkV && ViewCompat.canScrollHorizontally(v, -dx); + } + + @Override + public boolean dispatchKeyEvent(KeyEvent event) { + // Let the focused view and/or our descendants get the key first + return super.dispatchKeyEvent(event) || executeKeyEvent(event); + } + + /** + * You can call this function yourself to have the scroll view perform + * scrolling from a key event, just as if the event had been dispatched to + * it by the view hierarchy. + * + * @param event The key event to execute. + * @return Return true if the event was handled, else false. + */ + public boolean executeKeyEvent(KeyEvent event) { + boolean handled = false; + if (event.getAction() == KeyEvent.ACTION_DOWN) { + switch (event.getKeyCode()) { + case KeyEvent.KEYCODE_DPAD_LEFT: + handled = arrowScroll(FOCUS_LEFT); + break; + case KeyEvent.KEYCODE_DPAD_RIGHT: + handled = arrowScroll(FOCUS_RIGHT); + break; + case KeyEvent.KEYCODE_TAB: + if (Build.VERSION.SDK_INT >= 11) { + // The focus finder had a bug handling FOCUS_FORWARD and FOCUS_BACKWARD + // before Android 3.0. Ignore the tab key on those devices. + if (KeyEventCompat.hasNoModifiers(event)) { + handled = arrowScroll(FOCUS_FORWARD); + } else if (KeyEventCompat.hasModifiers(event, KeyEvent.META_SHIFT_ON)) { + handled = arrowScroll(FOCUS_BACKWARD); + } + } + break; + } + } + return handled; + } + + public boolean arrowScroll(int direction) { + View currentFocused = findFocus(); + if (currentFocused == this) { + currentFocused = null; + } else if (currentFocused != null) { + boolean isChild = false; + for (ViewParent parent = currentFocused.getParent(); parent instanceof ViewGroup; + parent = parent.getParent()) { + if (parent == this) { + isChild = true; + break; + } + } + if (!isChild) { + // This would cause the focus search down below to fail in fun ways. + final StringBuilder sb = new StringBuilder(); + sb.append(currentFocused.getClass().getSimpleName()); + for (ViewParent parent = currentFocused.getParent(); parent instanceof ViewGroup; + parent = parent.getParent()) { + sb.append(" => ").append(parent.getClass().getSimpleName()); + } + Log.e(TAG, "arrowScroll tried to find focus based on non-child " + + "current focused view " + sb.toString()); + currentFocused = null; + } + } + + boolean handled = false; + + View nextFocused = FocusFinder.getInstance().findNextFocus(this, currentFocused, + direction); + if (nextFocused != null && nextFocused != currentFocused) { + if (direction == View.FOCUS_LEFT) { + // If there is nothing to the left, or this is causing us to + // jump to the right, then what we really want to do is page left. + final int nextLeft = getChildRectInPagerCoordinates(mTempRect, nextFocused).left; + final int currLeft = getChildRectInPagerCoordinates(mTempRect, currentFocused).left; + if (currentFocused != null && nextLeft >= currLeft) { + handled = pageLeft(); + } else { + handled = nextFocused.requestFocus(); + } + } else if (direction == View.FOCUS_RIGHT) { + // If there is nothing to the right, or this is causing us to + // jump to the left, then what we really want to do is page right. + final int nextLeft = getChildRectInPagerCoordinates(mTempRect, nextFocused).left; + final int currLeft = getChildRectInPagerCoordinates(mTempRect, currentFocused).left; + if (currentFocused != null && nextLeft <= currLeft) { + handled = pageRight(); + } else { + handled = nextFocused.requestFocus(); + } + } + } else if (direction == FOCUS_LEFT || direction == FOCUS_BACKWARD) { + // Trying to move left and nothing there; try to page. + handled = pageLeft(); + } else if (direction == FOCUS_RIGHT || direction == FOCUS_FORWARD) { + // Trying to move right and nothing there; try to page. + handled = pageRight(); + } + if (handled) { + playSoundEffect(SoundEffectConstants.getContantForFocusDirection(direction)); + } + return handled; + } + + private Rect getChildRectInPagerCoordinates(Rect outRect, View child) { + if (outRect == null) { + outRect = new Rect(); + } + if (child == null) { + outRect.set(0, 0, 0, 0); + return outRect; + } + outRect.left = child.getLeft(); + outRect.right = child.getRight(); + outRect.top = child.getTop(); + outRect.bottom = child.getBottom(); + + ViewParent parent = child.getParent(); + while (parent instanceof ViewGroup && parent != this) { + final ViewGroup group = (ViewGroup) parent; + outRect.left += group.getLeft(); + outRect.right += group.getRight(); + outRect.top += group.getTop(); + outRect.bottom += group.getBottom(); + + parent = group.getParent(); + } + return outRect; + } + + boolean pageLeft() { + if (mCurItem > 0) { + setCurrentItem(mCurItem-1, true); + return true; + } + return false; + } + + boolean pageRight() { + if (mAdapter != null && mCurItem < (mAdapter.getCount()-1)) { + setCurrentItem(mCurItem+1, true); + return true; + } + return false; + } + + /** + * We only want the current page that is being shown to be focusable. + */ + @Override + public void addFocusables(ArrayList<View> views, int direction, int focusableMode) { + final int focusableCount = views.size(); + + final int descendantFocusability = getDescendantFocusability(); + + if (descendantFocusability != FOCUS_BLOCK_DESCENDANTS) { + for (int i = 0; i < getChildCount(); i++) { + final View child = getChildAt(i); + if (child.getVisibility() == VISIBLE) { + ItemInfo ii = infoForChild(child); + if (ii != null && ii.position == mCurItem) { + child.addFocusables(views, direction, focusableMode); + } + } + } + } + + // we add ourselves (if focusable) in all cases except for when we are + // FOCUS_AFTER_DESCENDANTS and there are some descendants focusable. this is + // to avoid the focus search finding layouts when a more precise search + // among the focusable children would be more interesting. + if ( + descendantFocusability != FOCUS_AFTER_DESCENDANTS || + // No focusable descendants + (focusableCount == views.size())) { + // Note that we can't call the superclass here, because it will + // add all views in. So we need to do the same thing View does. + if (!isFocusable()) { + return; + } + if ((focusableMode & FOCUSABLES_TOUCH_MODE) == FOCUSABLES_TOUCH_MODE && + isInTouchMode() && !isFocusableInTouchMode()) { + return; + } + if (views != null) { + views.add(this); + } + } + } + + /** + * We only want the current page that is being shown to be touchable. + */ + @Override + public void addTouchables(ArrayList<View> views) { + // Note that we don't call super.addTouchables(), which means that + // we don't call View.addTouchables(). This is okay because a ViewPager + // is itself not touchable. + for (int i = 0; i < getChildCount(); i++) { + final View child = getChildAt(i); + if (child.getVisibility() == VISIBLE) { + ItemInfo ii = infoForChild(child); + if (ii != null && ii.position == mCurItem) { + child.addTouchables(views); + } + } + } + } + + /** + * We only want the current page that is being shown to be focusable. + */ + @Override + protected boolean onRequestFocusInDescendants(int direction, + Rect previouslyFocusedRect) { + int index; + int increment; + int end; + int count = getChildCount(); + if ((direction & FOCUS_FORWARD) != 0) { + index = 0; + increment = 1; + end = count; + } else { + index = count - 1; + increment = -1; + end = -1; + } + for (int i = index; i != end; i += increment) { + View child = getChildAt(i); + if (child.getVisibility() == VISIBLE) { + ItemInfo ii = infoForChild(child); + if (ii != null && ii.position == mCurItem) { + if (child.requestFocus(direction, previouslyFocusedRect)) { + return true; + } + } + } + } + return false; + } + + @Override + public boolean dispatchPopulateAccessibilityEvent(AccessibilityEvent event) { + // Dispatch scroll events from this ViewPager. + if (event.getEventType() == AccessibilityEventCompat.TYPE_VIEW_SCROLLED) { + return super.dispatchPopulateAccessibilityEvent(event); + } + + // Dispatch all other accessibility events from the current page. + final int childCount = getChildCount(); + for (int i = 0; i < childCount; i++) { + final View child = getChildAt(i); + if (child.getVisibility() == VISIBLE) { + final ItemInfo ii = infoForChild(child); + if (ii != null && ii.position == mCurItem && + child.dispatchPopulateAccessibilityEvent(event)) { + return true; + } + } + } + + return false; + } + + @Override + protected ViewGroup.LayoutParams generateDefaultLayoutParams() { + return new LayoutParams(); + } + + @Override + protected ViewGroup.LayoutParams generateLayoutParams(ViewGroup.LayoutParams p) { + return generateDefaultLayoutParams(); + } + + @Override + protected boolean checkLayoutParams(ViewGroup.LayoutParams p) { + return p instanceof LayoutParams && super.checkLayoutParams(p); + } + + @Override + public ViewGroup.LayoutParams generateLayoutParams(AttributeSet attrs) { + return new LayoutParams(getContext(), attrs); + } + + @Override + public void onClick(View v) { + final ItemInfo ii = infoForChild(v); + + if (ii != null && mOnItemClickListener != null) { + mOnItemClickListener.onItemClick(ii.object, v, ii.position); + } + } + + @Override + public boolean onLongClick(View v) { + final ItemInfo ii = infoForChild(v); + + if (ii != null && mOnItemLongClickListener != null) { + return mOnItemLongClickListener.onItemLongClick(ii.object, v, ii.position); + } + + return false; + } + + private void updateViewOnClickListeners() { + final int childCount = getChildCount(); + for (int i = 0; i < childCount; i++) { + final View child = getChildAt(i); + final LayoutParams layoutParams = (LayoutParams) child.getLayoutParams(); + if (!layoutParams.isDecor) { + if (mOnItemClickListener != null) { + child.setOnClickListener(this); + } + } + } + } + + private void updateViewOnLongClickListeners() { + final int childCount = getChildCount(); + for (int i = 0; i < childCount; i++) { + final View child = getChildAt(i); + final LayoutParams layoutParams = (LayoutParams) child.getLayoutParams(); + if (!layoutParams.isDecor) { + if (mOnItemLongClickListener != null) { + child.setOnLongClickListener(this); + } + } + } + } + + public void setOnItemClickListener(OnItemClickListener onItemClickListener) { + if (mOnItemClickListener != onItemClickListener) { + mOnItemClickListener = onItemClickListener; + updateViewOnClickListeners(); + } + } + + public void setOnItemLongClickListener(OnItemLongClickListener onItemLongClickListener) { + if (mOnItemLongClickListener != onItemLongClickListener) { + mOnItemLongClickListener = onItemLongClickListener; + updateViewOnLongClickListeners(); + } + } + + class MyAccessibilityDelegate extends AccessibilityDelegateCompat { + + @Override + public void onInitializeAccessibilityEvent(View host, AccessibilityEvent event) { + super.onInitializeAccessibilityEvent(host, event); + event.setClassName(VelocityViewPager.class.getName()); + final AccessibilityRecordCompat recordCompat = AccessibilityRecordCompat.obtain(); + recordCompat.setScrollable(canScroll()); + if (event.getEventType() == AccessibilityEventCompat.TYPE_VIEW_SCROLLED + && mAdapter != null) { + recordCompat.setItemCount(mAdapter.getCount()); + recordCompat.setFromIndex(mCurItem); + recordCompat.setToIndex(mCurItem); + } + } + + @Override + public void onInitializeAccessibilityNodeInfo(View host, AccessibilityNodeInfoCompat info) { + super.onInitializeAccessibilityNodeInfo(host, info); + info.setClassName(VelocityViewPager.class.getName()); + info.setScrollable(canScroll()); + if (canScrollHorizontally(1)) { + info.addAction(AccessibilityNodeInfoCompat.ACTION_SCROLL_FORWARD); + } + if (canScrollHorizontally(-1)) { + info.addAction(AccessibilityNodeInfoCompat.ACTION_SCROLL_BACKWARD); + } + } + + @Override + public boolean performAccessibilityAction(View host, int action, Bundle args) { + if (super.performAccessibilityAction(host, action, args)) { + return true; + } + switch (action) { + case AccessibilityNodeInfoCompat.ACTION_SCROLL_FORWARD: { + if (canScrollHorizontally(1)) { + setCurrentItem(mCurItem + 1); + return true; + } + } return false; + case AccessibilityNodeInfoCompat.ACTION_SCROLL_BACKWARD: { + if (canScrollHorizontally(-1)) { + setCurrentItem(mCurItem - 1); + return true; + } + } return false; + } + return false; + } + + private boolean canScroll() { + return (mAdapter != null) && (mAdapter.getCount() > 1); + } + } + + private class PagerObserver extends DataSetObserver { + @Override + public void onChanged() { + dataSetChanged(); + } + @Override + public void onInvalidated() { + dataSetChanged(); + } + } + + /** + * Layout parameters that should be supplied for views added to a + * ViewPager. + */ + public static class LayoutParams extends ViewGroup.LayoutParams { + /** + * true if this view is a decoration on the pager itself and not + * a view supplied by the adapter. + */ + public boolean isDecor; + + /** + * Gravity setting for use on decor views only: + * Where to position the view page within the overall ViewPager + * container; constants are defined in {@link android.view.Gravity}. + */ + public int gravity; + + /** + * Width as a 0-1 multiplier of the measured pager width + */ + float widthFactor = 0.f; + + /** + * true if this view was added during layout and needs to be measured + * before being positioned. + */ + boolean needsMeasure; + + /** + * Adapter position this view is for if !isDecor + */ + int position; + + /** + * Current child index within the ViewPager that this view occupies + */ + int childIndex; + + public LayoutParams() { + super(FILL_PARENT, FILL_PARENT); + } + + public LayoutParams(Context context, AttributeSet attrs) { + super(context, attrs); + + final TypedArray a = context.obtainStyledAttributes(attrs, LAYOUT_ATTRS); + gravity = a.getInteger(0, Gravity.TOP); + a.recycle(); + } + } + + public interface OnItemClickListener { + void onItemClick(Object object, View view, int position); + } + + public interface OnItemLongClickListener { + boolean onItemLongClick(Object object, View view, int position); + } +}
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