Add Transitions useful for Activity transitions.

Slide: transition in and out of the edge of the scene.
Explode: transition to the scene borders

Moved capability from Fade to Visibility.

Change-Id: Ibeb0d8f751c990edc467570d9665fbe251af2703

1 files changed, 165 insertions, 0 deletions

diff --git a/core/java/android/transition/SidePropagation.java b/core/java/android/transition/SidePropagation.java
new file mode 100644
index 0000000..c331945
--- /dev/null
+++ b/core/java/android/transition/SidePropagation.java
@@ -0,0 +1,165 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * 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 android.transition;
+
+import android.graphics.Rect;
+import android.util.FloatMath;
+import android.util.Log;
+import android.view.View;
+import android.view.ViewGroup;
+
+/**
+ * A <code>TransitionPropagation</code> that propagates based on the distance to the side
+ * and, orthogonally, the distance to epicenter. If the transitioning View is visible in
+ * the start of the transition, then it will transition sooner when closer to the side and
+ * later when farther. If the view is not visible in the start of the transition, then
+ * it will transition later when closer to the side and sooner when farther from the edge.
+ * This is the default TransitionPropagation used with {@link android.transition.Slide}.
+ */
+public class SidePropagation extends VisibilityPropagation {
+    private static final String TAG = "SlidePropagation";
+
+    /**
+     * Transition propagates relative to the distance of the left side of the scene.
+     */
+    public static final int LEFT = Slide.LEFT;
+
+    /**
+     * Transition propagates relative to the distance of the top of the scene.
+     */
+    public static final int TOP = Slide.TOP;
+
+    /**
+     * Transition propagates relative to the distance of the right side of the scene.
+     */
+    public static final int RIGHT = Slide.RIGHT;
+
+    /**
+     * Transition propagates relative to the distance of the bottom of the scene.
+     */
+    public static final int BOTTOM = Slide.BOTTOM;
+
+    private float mPropagationSpeed = 4.0f;
+    private int mSide = BOTTOM;
+
+    /**
+     * Sets the side that is used to calculate the transition propagation. If the transitioning
+     * View is visible in the start of the transition, then it will transition sooner when
+     * closer to the side and later when farther. If the view is not visible in the start of
+     * the transition, then it will transition later when closer to the side and sooner when
+     * farther from the edge. The default is {@link #BOTTOM}.
+     *
+     * @param side The side that is used to calculate the transition propagation. Must be one of
+     *             {@link #LEFT}, {@link #TOP}, {@link #RIGHT}, or {@link #BOTTOM}.
+     */
+    public void setSide(int side) {
+        mSide = side;
+    }
+
+    /**
+     * Sets the speed at which transition propagation happens, relative to the duration of the
+     * Transition. A <code>propagationSpeed</code> of 1 means that a View centered at the side
+     * set in {@link #setSide(int)} and View centered at the opposite edge will have a difference
+     * in start delay of approximately the duration of the Transition. A speed of 2 means the
+     * start delay difference will be approximately half of the duration of the transition. A
+     * value of 0 is illegal, but negative values will invert the propagation.
+     *
+     * @param propagationSpeed The speed at which propagation occurs, relative to the duration
+     *                         of the transition. A speed of 4 means it works 4 times as fast
+     *                         as the duration of the transition. May not be 0.
+     */
+    public void setPropagationSpeed(float propagationSpeed) {
+        if (propagationSpeed == 0) {
+            throw new IllegalArgumentException("propagationSpeed may not be 0");
+        }
+        mPropagationSpeed = propagationSpeed;
+    }
+
+    @Override
+    public long getStartDelay(ViewGroup sceneRoot, Transition transition,
+            TransitionValues startValues, TransitionValues endValues) {
+        if (startValues == null && endValues == null) {
+            return 0;
+        }
+        int directionMultiplier = 1;
+        Rect epicenter = transition.getEpicenter();
+        TransitionValues positionValues;
+        if (endValues == null || getViewVisibility(startValues) == View.VISIBLE) {
+            positionValues = startValues;
+            directionMultiplier = -1;
+        } else {
+            positionValues = endValues;
+        }
+
+        int viewCenterX = getViewX(positionValues);
+        int viewCenterY = getViewY(positionValues);
+
+        int[] loc = new int[2];
+        sceneRoot.getLocationOnScreen(loc);
+        int left = loc[0] + Math.round(sceneRoot.getTranslationX());
+        int top = loc[1] + Math.round(sceneRoot.getTranslationY());
+        int right = left + sceneRoot.getWidth();
+        int bottom = top + sceneRoot.getHeight();
+
+        int epicenterX;
+        int epicenterY;
+        if (epicenter != null) {
+            epicenterX = epicenter.centerX();
+            epicenterY = epicenter.centerY();
+        } else {
+            epicenterX = (left + right) / 2;
+            epicenterY = (top + bottom) / 2;
+        }
+
+        float distance = distance(viewCenterX, viewCenterY, epicenterX, epicenterY,
+                left, top, right, bottom);
+        float maxDistance = getMaxDistance(sceneRoot);
+        float distanceFraction = distance/maxDistance;
+
+        return Math.round(transition.getDuration() * directionMultiplier / mPropagationSpeed
+                * distanceFraction);
+    }
+
+    private int distance(int viewX, int viewY, int epicenterX, int epicenterY,
+            int left, int top, int right, int bottom) {
+        int distance = 0;
+        switch (mSide) {
+            case LEFT:
+                distance = right - viewX + Math.abs(epicenterY - viewY);
+                break;
+            case TOP:
+                distance = bottom - viewY + Math.abs(epicenterX - viewX);
+                break;
+            case RIGHT:
+                distance = viewX - left + Math.abs(epicenterY - viewY);
+                break;
+            case BOTTOM:
+                distance = viewY - top + Math.abs(epicenterX - viewX);
+                break;
+        }
+        return distance;
+    }
+
+    private int getMaxDistance(ViewGroup sceneRoot) {
+        switch (mSide) {
+            case LEFT:
+            case RIGHT:
+                return sceneRoot.getWidth();
+            default:
+                return sceneRoot.getHeight();
+        }
+    }
+}