Fixing the case of less than or equal to 5 items in StackView

Change-Id: I9226fe8343902e06e2f4b04837e232f1744786a8

2 files changed, 74 insertions, 55 deletions

diff --git a/core/java/android/widget/AdapterViewAnimator.java b/core/java/android/widget/AdapterViewAnimator.java
index 87453ae..bb2e26c3 100644
--- a/core/java/android/widget/AdapterViewAnimator.java
+++ b/core/java/android/widget/AdapterViewAnimator.java
@@ -69,12 +69,12 @@ public abstract class AdapterViewAnimator extends AdapterView<Adapter>
      * The number of views that the {@link AdapterViewAnimator} keeps as children at any
      * given time (not counting views that are pending removal, see {@link #mPreviousViews}).
      */
-    int mNumActiveViews = 1;
+    int mMaxNumActiveViews = 1;
 
     /**
      * Map of the children of the {@link AdapterViewAnimator}.
      */
-    private HashMap<Integer, ViewAndIndex> mViewsMap = new HashMap<Integer, ViewAndIndex>();
+    HashMap<Integer, ViewAndIndex> mViewsMap = new HashMap<Integer, ViewAndIndex>();
 
     /**
      * List of views pending removal from the {@link AdapterViewAnimator}
@@ -141,8 +141,6 @@ public abstract class AdapterViewAnimator extends AdapterView<Adapter>
     ObjectAnimator mInAnimation;
     ObjectAnimator mOutAnimation;
 
-    private  ArrayList<View> mViewsToBringToFront;
-
     private static final int DEFAULT_ANIMATION_DURATION = 200;
 
     public AdapterViewAnimator(Context context) {
@@ -188,10 +186,9 @@ public abstract class AdapterViewAnimator extends AdapterView<Adapter>
     private void initViewAnimator() {
         mMainQueue = new Handler(Looper.myLooper());
         mPreviousViews = new ArrayList<Integer>();
-        mViewsToBringToFront = new ArrayList<View>();
     }
 
-    private class ViewAndIndex {
+    class ViewAndIndex {
         ViewAndIndex(View v, int i) {
             view = v;
             index = i;
@@ -217,7 +214,7 @@ public abstract class AdapterViewAnimator extends AdapterView<Adapter>
         if (activeOffset > numVisibleViews - 1) {
             // Throw an exception here.
         }
-        mNumActiveViews = numVisibleViews;
+        mMaxNumActiveViews = numVisibleViews;
         mActiveOffset = activeOffset;
         mPreviousViews.clear();
         mViewsMap.clear();
@@ -266,10 +263,10 @@ public abstract class AdapterViewAnimator extends AdapterView<Adapter>
     public void setDisplayedChild(int whichChild) {
         if (mAdapter != null) {
             mWhichChild = whichChild;
-            if (whichChild >= mAdapter.getCount()) {
-                mWhichChild = mLoopViews ? 0 : mAdapter.getCount() - 1;
+            if (whichChild >= getWindowSize()) {
+                mWhichChild = mLoopViews ? 0 : getWindowSize() - 1;
             } else if (whichChild < 0) {
-                mWhichChild = mLoopViews ? mAdapter.getCount() - 1 : 0;
+                mWhichChild = mLoopViews ? getWindowSize() - 1 : 0;
             }
 
             boolean hasFocus = getFocusedChild() != null;
@@ -327,7 +324,7 @@ public abstract class AdapterViewAnimator extends AdapterView<Adapter>
         showOnly(childIndex, animate, false);
     }
 
-    private int modulo(int pos, int size) {
+    int modulo(int pos, int size) {
         if (size > 0) {
             return (size + (pos % size)) % size;
         } else {
@@ -342,9 +339,8 @@ public abstract class AdapterViewAnimator extends AdapterView<Adapter>
      * @return View at this index, null if the index is outside the bounds
      */
     View getViewAtRelativeIndex(int relativeIndex) {
-        if (relativeIndex >= 0 && relativeIndex <= mNumActiveViews - 1 && mAdapter != null) {
-            int adapterCount =  mAdapter.getCount();
-            int i = modulo(mCurrentWindowStartUnbounded + relativeIndex, adapterCount);
+        if (relativeIndex >= 0 && relativeIndex <= getNumActiveViews() - 1 && mAdapter != null) {
+            int i = modulo(mCurrentWindowStartUnbounded + relativeIndex, getWindowSize());
             if (mViewsMap.get(i) != null) {
                 return mViewsMap.get(i).view;
             }
@@ -352,6 +348,27 @@ public abstract class AdapterViewAnimator extends AdapterView<Adapter>
         return null;
     }
 
+    int getNumActiveViews() {
+        if (mAdapter != null) {
+            return Math.min(mAdapter.getCount() + 1, mMaxNumActiveViews);
+        } else {
+            return mMaxNumActiveViews;
+        }
+    }
+
+    int getWindowSize() {
+        if (mAdapter != null) {
+            int adapterCount = mAdapter.getCount();
+            if (adapterCount <= getNumActiveViews() && mLoopViews) {
+                return adapterCount*mMaxNumActiveViews;
+            } else {
+                return adapterCount;
+            }
+        } else {
+            return 0;
+        }
+    }
+
     LayoutParams createOrReuseLayoutParams(View v) {
         final ViewGroup.LayoutParams currentLp = v.getLayoutParams();
         if (currentLp instanceof ViewGroup.LayoutParams) {
@@ -363,7 +380,7 @@ public abstract class AdapterViewAnimator extends AdapterView<Adapter>
 
     void refreshChildren() {
         for (int i = mCurrentWindowStart; i <= mCurrentWindowEnd; i++) {
-            int index = modulo(i, mNumActiveViews);
+            int index = modulo(i, mMaxNumActiveViews);
 
             // get the fresh child from the adapter
             View updatedChild = mAdapter.getView(i, null, this);
@@ -412,7 +429,7 @@ public abstract class AdapterViewAnimator extends AdapterView<Adapter>
         }
         mPreviousViews.clear();
         int newWindowStartUnbounded = childIndex - mActiveOffset;
-        int newWindowEndUnbounded = newWindowStartUnbounded + mNumActiveViews - 1;
+        int newWindowEndUnbounded = newWindowStartUnbounded + getNumActiveViews() - 1;
         int newWindowStart = Math.max(0, newWindowStartUnbounded);
         int newWindowEnd = Math.min(adapterCount - 1, newWindowEndUnbounded);
 
@@ -420,8 +437,8 @@ public abstract class AdapterViewAnimator extends AdapterView<Adapter>
             newWindowStart = newWindowStartUnbounded;
             newWindowEnd = newWindowEndUnbounded;
         }
-        int rangeStart = modulo(newWindowStart, adapterCount);
-        int rangeEnd = modulo(newWindowEnd, adapterCount);
+        int rangeStart = modulo(newWindowStart, getWindowSize());
+        int rangeEnd = modulo(newWindowEnd, getWindowSize());
 
         boolean wrap = false;
         if (rangeStart > rangeEnd) {
@@ -450,11 +467,12 @@ public abstract class AdapterViewAnimator extends AdapterView<Adapter>
         }
 
         // If the window has changed
-        if (!(newWindowStart == mCurrentWindowStart && newWindowEnd == mCurrentWindowEnd)) {
+        if (!(newWindowStart == mCurrentWindowStart && newWindowEnd == mCurrentWindowEnd &&
+              newWindowStartUnbounded == mCurrentWindowStartUnbounded)) {
             // Run through the indices in the new range
             for (int i = newWindowStart; i <= newWindowEnd; i++) {
 
-                int index = modulo(i, adapterCount);
+                int index = modulo(i, getWindowSize());
                 int oldRelativeIndex;
                 if (mViewsMap.containsKey(index)) {
                     oldRelativeIndex = mViewsMap.get(index).index;
@@ -494,13 +512,6 @@ public abstract class AdapterViewAnimator extends AdapterView<Adapter>
                 }
                 mViewsMap.get(index).view.bringToFront();
             }
-
-            for (int i = 0; i < mViewsToBringToFront.size(); i++) {
-                View v = mViewsToBringToFront.get(i);
-                v.bringToFront();
-            }
-            mViewsToBringToFront.clear();
-
             mCurrentWindowStart = newWindowStart;
             mCurrentWindowEnd = newWindowEnd;
             mCurrentWindowStartUnbounded = newWindowStartUnbounded;
diff --git a/core/java/android/widget/StackView.java b/core/java/android/widget/StackView.java
index 4c3927b..c05da03 100644
--- a/core/java/android/widget/StackView.java
+++ b/core/java/android/widget/StackView.java
@@ -129,7 +129,7 @@ public class StackView extends AdapterViewAnimator {
     }
 
     private void initStackView() {
-        configureViewAnimator(NUM_ACTIVE_VIEWS, NUM_ACTIVE_VIEWS - 2);
+        configureViewAnimator(NUM_ACTIVE_VIEWS, 1);
         setStaticTransformationsEnabled(true);
         final ViewConfiguration configuration = ViewConfiguration.get(getContext());
         mTouchSlop = configuration.getScaledTouchSlop();
@@ -165,7 +165,7 @@ public class StackView extends AdapterViewAnimator {
      * Animate the views between different relative indexes within the {@link AdapterViewAnimator}
      */
     void animateViewForTransition(int fromIndex, int toIndex, View view) {
-        if (fromIndex == -1 && toIndex == 0) {
+        if (fromIndex == -1 && toIndex != 0) {
             // Fade item in
             if (view.getAlpha() == 1) {
                 view.setAlpha(0);
@@ -175,7 +175,7 @@ public class StackView extends AdapterViewAnimator {
             ObjectAnimator fadeIn = ObjectAnimator.ofFloat(view, "alpha", view.getAlpha(), 1.0f);
             fadeIn.setDuration(DEFAULT_ANIMATION_DURATION);
             fadeIn.start();
-        } else if (fromIndex == mNumActiveViews - 1 && toIndex == mNumActiveViews - 2) {
+        } else if (fromIndex == 0 && toIndex == 1) {
             // Slide item in
             view.setVisibility(VISIBLE);
 
@@ -189,7 +189,7 @@ public class StackView extends AdapterViewAnimator {
             pa.setDuration(duration);
             pa.setInterpolator(new LinearInterpolator());
             pa.start();
-        } else if (fromIndex == mNumActiveViews - 2 && toIndex == mNumActiveViews - 1) {
+        } else if (fromIndex == 1 && toIndex == 0) {
             // Slide item out
             int duration = Math.round(mStackSlider.getDurationForOffscreenPosition(mYVelocity));
 
@@ -201,7 +201,7 @@ public class StackView extends AdapterViewAnimator {
             pa.setDuration(duration);
             pa.setInterpolator(new LinearInterpolator());
             pa.start();
-        } else if (fromIndex == -1 && toIndex == mNumActiveViews - 1) {
+        } else if (fromIndex == -1 && toIndex == 0) {
             // Make sure this view that is "waiting in the wings" is invisible
             view.setAlpha(0.0f);
             view.setVisibility(INVISIBLE);
@@ -223,9 +223,10 @@ public class StackView extends AdapterViewAnimator {
     private void transformViewAtIndex(int index, View view) {
         float maxPerpectiveShift = mMeasuredHeight * PERSPECTIVE_SHIFT_FACTOR;
 
-        if (index == mNumActiveViews -1) index--;
+        index = mMaxNumActiveViews - index - 1;
+        if (index == mMaxNumActiveViews - 1) index--;
 
-        float r = (index * 1.0f) / (mNumActiveViews - 2);
+        float r = (index * 1.0f) / (mMaxNumActiveViews - 2);
 
         float scale = 1 - PERSPECTIVE_SCALE_FACTOR * (1 - r);
         PropertyValuesHolder scaleX = PropertyValuesHolder.ofFloat("scaleX", scale);
@@ -245,8 +246,20 @@ public class StackView extends AdapterViewAnimator {
         pa.start();
     }
 
+    @Override
+    void showOnly(int childIndex, boolean animate, boolean onLayout) {
+        super.showOnly(childIndex, animate, onLayout);
+
+        // Here we need to make sure that the z-order of the children is correct
+	for (int i = mCurrentWindowEnd; i >= mCurrentWindowStart; i--) {
+            int index = modulo(i, getWindowSize());
+            View v = mViewsMap.get(index).view;
+            if (v != null) v.bringToFront();
+        }
+    }
+
     private void updateChildTransforms() {
-        for (int i = 0; i < mNumActiveViews - 1; i++) {
+        for (int i = 0; i < getNumActiveViews(); i++) {
             View v = getViewAtRelativeIndex(i);
             if (v != null) {
                 transformViewAtIndex(i, v);
@@ -341,19 +354,17 @@ public class StackView extends AdapterViewAnimator {
 
             int activeIndex;
             if (mStackMode == ITEMS_SLIDE_UP) {
-                activeIndex = (swipeGestureType == GESTURE_SLIDE_DOWN) ?
-                        mNumActiveViews - 1 : mNumActiveViews - 2;
+                activeIndex = (swipeGestureType == GESTURE_SLIDE_DOWN) ? 0 : 1;
             } else {
-                activeIndex = (swipeGestureType == GESTURE_SLIDE_DOWN) ?
-                        mNumActiveViews - 2 : mNumActiveViews - 1;
+                activeIndex = (swipeGestureType == GESTURE_SLIDE_DOWN) ? 1 : 0;
             }
 
             if (mLoopViews) {
                 mStackSlider.setMode(StackSlider.NORMAL_MODE);
-            } else if (mCurrentWindowStartUnbounded + activeIndex == 0) {
+            } else if (mCurrentWindowStartUnbounded + activeIndex == -1) {
+                activeIndex++;
                 mStackSlider.setMode(StackSlider.BEGINNING_OF_STACK_MODE);
-            } else if (mCurrentWindowStartUnbounded + activeIndex == mAdapter.getCount()) {
-                activeIndex--;
+            } else if (mCurrentWindowStartUnbounded + activeIndex == mAdapter.getCount() - 1) {
                 mStackSlider.setMode(StackSlider.END_OF_STACK_MODE);
             } else {
                 mStackSlider.setMode(StackSlider.NORMAL_MODE);
@@ -439,8 +450,7 @@ public class StackView extends AdapterViewAnimator {
         final int pointerId = ev.getPointerId(activePointerIndex);
         if (pointerId == mActivePointerId) {
 
-            int activeViewIndex = (mSwipeGestureType == GESTURE_SLIDE_DOWN) ? mNumActiveViews - 1
-                    : mNumActiveViews - 2;
+            int activeViewIndex = (mSwipeGestureType == GESTURE_SLIDE_DOWN) ? 0 : 1;
 
             View v = getViewAtRelativeIndex(activeViewIndex);
             if (v == null) return;
@@ -498,18 +508,18 @@ public class StackView extends AdapterViewAnimator {
                 && mStackSlider.mMode == StackSlider.NORMAL_MODE) {
             // Swipe threshold exceeded, swipe down
             if (mStackMode == ITEMS_SLIDE_UP) {
-                showNext();
-            } else {
                 showPrevious();
+            } else {
+                showNext();
             }
             mHighlight.bringToFront();
         } else if (deltaY < -mSwipeThreshold && mSwipeGestureType == GESTURE_SLIDE_UP
                 && mStackSlider.mMode == StackSlider.NORMAL_MODE) {
             // Swipe threshold exceeded, swipe up
             if (mStackMode == ITEMS_SLIDE_UP) {
-                showPrevious();
-            } else {
                 showNext();
+            } else {
+                showPrevious();
             }
 
             mHighlight.bringToFront();
@@ -643,13 +653,13 @@ public class StackView extends AdapterViewAnimator {
                     mView.setRotationX(stackDirection * 90.0f * rotationInterpolator(r));
                     mHighlight.setRotationX(stackDirection * 90.0f * rotationInterpolator(r));
                     break;
-                case BEGINNING_OF_STACK_MODE:
+                case END_OF_STACK_MODE:
                     r = r * 0.2f;
                     viewLp.setVerticalOffset(Math.round(-stackDirection * r * mSlideAmount));
                     highlightLp.setVerticalOffset(Math.round(-stackDirection * r * mSlideAmount));
                     mHighlight.setAlpha(highlightAlphaInterpolator(r));
                     break;
-                case END_OF_STACK_MODE:
+                case BEGINNING_OF_STACK_MODE:
                     r = (1-r) * 0.2f;
                     viewLp.setVerticalOffset(Math.round(stackDirection * r * mSlideAmount));
                     highlightLp.setVerticalOffset(Math.round(stackDirection * r * mSlideAmount));
@@ -735,12 +745,10 @@ public class StackView extends AdapterViewAnimator {
     public void onRemoteAdapterConnected() {
         super.onRemoteAdapterConnected();
         // On first run, we want to set the stack to the end.
-        if (mAdapter != null && mWhichChild == -1) {
-            mWhichChild = mAdapter.getCount() - 1;
-        }
-        if (mWhichChild >= 0) {
-            setDisplayedChild(mWhichChild);
+        if (mWhichChild == -1) {
+            mWhichChild = 0;
         }
+        setDisplayedChild(mWhichChild);
     }
 
     LayoutParams createOrReuseLayoutParams(View v) {