Fix Fade transition interrupt.

Bug 26963113

When a Fade transition is interrupted and reversed, the
View started the animation from the beginning. This change
captures the previous transitionAlpha and starts the animation
from the previous alpha state.

Change-Id: I801fe9ade6af4cf8446838e231bdc71841668a18
(cherry picked from commit 3cf9fa3db0231d035142c27992818d8f7827ac3e)

1 files changed, 21 insertions, 16 deletions

diff --git a/core/java/android/transition/Fade.java b/core/java/android/transition/Fade.java
index 287c69608b8b..b2e8d3351028 100644
--- a/core/java/android/transition/Fade.java
+++ b/core/java/android/transition/Fade.java
@@ -57,9 +57,9 @@ import android.view.ViewGroup;
  * tag <code>fade</code>, along with the standard
  * attributes of {@link android.R.styleable#Fade} and
  * {@link android.R.styleable#Transition}.</p>
-
  */
 public class Fade extends Visibility {
+    static final String PROPNAME_TRANSITION_ALPHA = "android:fade:transitionAlpha";
 
     private static boolean DBG = Transition.DBG && false;
 
@@ -105,6 +105,13 @@ public class Fade extends Visibility {
         setMode(fadingMode);
     }
 
+    @Override
+    public void captureStartValues(TransitionValues transitionValues) {
+        super.captureStartValues(transitionValues);
+        transitionValues.values.put(PROPNAME_TRANSITION_ALPHA,
+                transitionValues.view.getTransitionAlpha());
+    }
+
     /**
      * Utility method to handle creating and running the Animator.
      */
@@ -119,7 +126,6 @@ public class Fade extends Visibility {
         }
         final FadeAnimatorListener listener = new FadeAnimatorListener(view);
         anim.addListener(listener);
-        anim.addPauseListener(listener);
         addListener(new TransitionListenerAdapter() {
             @Override
             public void onTransitionEnd(Transition transition) {
@@ -138,18 +144,28 @@ public class Fade extends Visibility {
             Log.d(LOG_TAG, "Fade.onAppear: startView, startVis, endView, endVis = " +
                     startView + ", " + view);
         }
-        return createAnimation(view, 0, 1);
+        float startAlpha = 0;
+        if (startValues != null) {
+            startAlpha = (Float) startValues.values.get(PROPNAME_TRANSITION_ALPHA);
+            if (startAlpha == 1) {
+                startAlpha = 0;
+            }
+        }
+        return createAnimation(view, startAlpha, 1);
     }
 
     @Override
     public Animator onDisappear(ViewGroup sceneRoot, final View view, TransitionValues startValues,
             TransitionValues endValues) {
-        return createAnimation(view, 1, 0);
+        float startAlpha = 1;
+        if (startValues != null) {
+            startAlpha = (Float) startValues.values.get(PROPNAME_TRANSITION_ALPHA);
+        }
+        return createAnimation(view, startAlpha, 0);
     }
 
     private static class FadeAnimatorListener extends AnimatorListenerAdapter {
         private final View mView;
-        private float mPausedAlpha = -1;
         private boolean mLayerTypeChanged = false;
 
         public FadeAnimatorListener(View view) {
@@ -171,16 +187,5 @@ public class Fade extends Visibility {
                 mView.setLayerType(View.LAYER_TYPE_NONE, null);
             }
         }
-
-        @Override
-        public void onAnimationPause(Animator animator) {
-            mPausedAlpha = mView.getTransitionAlpha();
-            mView.setTransitionAlpha(1);
-        }
-
-        @Override
-        public void onAnimationResume(Animator animator) {
-            mView.setTransitionAlpha(mPausedAlpha);
-        }
     }
 }