Fix animation not playing when going home while another animation is playing

When going to a new state, we cancel any currently playing animation. When
canceling the animation, we reset mState = mCurrentStableState. Thus, when
determining the duration of the new animation, we have both state == NORMAL
and mState == NORMAL, leading to a duration of 0 and therefore no animation.
Storing the fromState before canceling/resetting fixes the issue.

Change-Id: I92332deae8058c4dd41212fe7f749955ede28b1c

src/com/android/launcher3/LauncherStateManager.java

@@ -17,7 +17,6 @@
 package com.android.launcher3;
 
 import static android.view.View.VISIBLE;
-
 import static com.android.launcher3.LauncherState.NORMAL;
 import static com.android.launcher3.anim.AnimatorSetBuilder.ANIM_OVERVIEW_FADE;
 import static com.android.launcher3.anim.AnimatorSetBuilder.ANIM_OVERVIEW_SCALE;
@@ -222,7 +221,8 @@ public class LauncherStateManager {
             }
         }
 
-        // Cancel the current animation
+        // Cancel the current animation. This will reset mState to mCurrentStableState, so store it.
+        LauncherState fromState = mState;
         mConfig.reset();
 
         if (!animated) {
@@ -245,10 +245,10 @@ public class LauncherStateManager {
 
         // Since state NORMAL can be reached from multiple states, just assume that the
         // transition plays in reverse and use the same duration as previous state.
-        mConfig.duration = state == NORMAL ? mState.transitionDuration : state.transitionDuration;
+        mConfig.duration = state == NORMAL ? fromState.transitionDuration : state.transitionDuration;
 
         AnimatorSetBuilder builder = new AnimatorSetBuilder();
-        prepareForAtomicAnimation(mState, state, builder);
+        prepareForAtomicAnimation(fromState, state, builder);
         AnimatorSet animation = createAnimationToNewWorkspaceInternal(
                 state, builder, onCompleteRunnable);
         Runnable runnable = new StartAnimRunnable(animation);