Don't use transient states for wallpaper animation.

The WindowManagerService member mLowerWallpaperTarget is not stable
throughout an app transition. Relying on it to be stable causes the
intra-wallpaper animation to start out right but after the windows
have been relayed out there is no longer a lower wallpaper target.
This causes the wallpaper to start tracking the animation of the
current wallpaper target rather than remain stable.

Switching to a new variable that saves the state of wallpaper
animation at the start of the animation fixes bug 11240590.

Change-Id: I336a59c47665fcf61019f567b8663956ff0e4940

3 files changed, 10 insertions, 11 deletions

diff --git a/services/java/com/android/server/wm/WindowAnimator.java b/services/java/com/android/server/wm/WindowAnimator.java
index ca87b4f..cd46bb8 100644
--- a/services/java/com/android/server/wm/WindowAnimator.java
+++ b/services/java/com/android/server/wm/WindowAnimator.java
@@ -121,12 +121,6 @@ public class WindowAnimator {
         mDisplayContentsAnimators.delete(displayId);
     }
 
-    AppWindowAnimator getWallpaperAppAnimator() {
-        return mService.mWallpaperTarget == null
-                ? null : mService.mWallpaperTarget.mAppToken == null
-                        ? null : mService.mWallpaperTarget.mAppToken.mAppAnimator;
-    }
-
     void hideWallpapersLocked(final WindowState w) {
         final WindowState wallpaperTarget = mService.mWallpaperTarget;
         final WindowState lowerWallpaperTarget = mService.mLowerWallpaperTarget;
diff --git a/services/java/com/android/server/wm/WindowManagerService.java b/services/java/com/android/server/wm/WindowManagerService.java
index 55d2e5d..f2a0cbd 100644
--- a/services/java/com/android/server/wm/WindowManagerService.java
+++ b/services/java/com/android/server/wm/WindowManagerService.java
@@ -530,6 +530,7 @@ public class WindowManagerService extends IWindowManager.Stub
     static final long WALLPAPER_TIMEOUT = 150;
     // Time we wait after a timeout before trying to wait again.
     static final long WALLPAPER_TIMEOUT_RECOVERY = 10000;
+    boolean mAnimateWallpaperWithTarget;
 
     AppWindowToken mFocusedApp = null;
 
@@ -8490,6 +8491,7 @@ public class WindowManagerService extends IWindowManager.Stub
                 }
             }
 
+            mAnimateWallpaperWithTarget = false;
             if (closingAppHasWallpaper && openingAppHasWallpaper) {
                 if (DEBUG_APP_TRANSITIONS) Slog.v(TAG, "Wallpaper animation!");
                 switch (transit) {
@@ -8517,6 +8519,8 @@ public class WindowManagerService extends IWindowManager.Stub
                 transit = AppTransition.TRANSIT_WALLPAPER_OPEN;
                 if (DEBUG_APP_TRANSITIONS) Slog.v(TAG,
                         "New transit into wallpaper: " + transit);
+            } else {
+                mAnimateWallpaperWithTarget = true;
             }
 
             // If all closing windows are obscured, then there is
diff --git a/services/java/com/android/server/wm/WindowStateAnimator.java b/services/java/com/android/server/wm/WindowStateAnimator.java
index e2fae89..af00d83 100644
--- a/services/java/com/android/server/wm/WindowStateAnimator.java
+++ b/services/java/com/android/server/wm/WindowStateAnimator.java
@@ -845,9 +845,9 @@ class WindowStateAnimator {
 
         // Wallpapers are animated based on the "real" window they
         // are currently targeting.
-        if (mIsWallpaper && mService.mLowerWallpaperTarget == null
-                && mService.mWallpaperTarget != null) {
-            final WindowStateAnimator wallpaperAnimator = mService.mWallpaperTarget.mWinAnimator;
+        final WindowState wallpaperTarget = mService.mWallpaperTarget;
+        if (mIsWallpaper && wallpaperTarget != null && mService.mAnimateWallpaperWithTarget) {
+            final WindowStateAnimator wallpaperAnimator = wallpaperTarget.mWinAnimator;
             if (wallpaperAnimator.mHasLocalTransformation &&
                     wallpaperAnimator.mAnimation != null &&
                     !wallpaperAnimator.mAnimation.getDetachWallpaper()) {
@@ -856,8 +856,9 @@ class WindowStateAnimator {
                     Slog.v(TAG, "WP target attached xform: " + attachedTransformation);
                 }
             }
-            final AppWindowAnimator wpAppAnimator = mAnimator.getWallpaperAppAnimator();
-            if (wpAppAnimator != null && wpAppAnimator.hasTransformation
+            final AppWindowAnimator wpAppAnimator = wallpaperTarget.mAppToken == null ?
+                    null : wallpaperTarget.mAppToken.mAppAnimator;
+                if (wpAppAnimator != null && wpAppAnimator.hasTransformation
                     && wpAppAnimator.animation != null
                     && !wpAppAnimator.animation.getDetachWallpaper()) {
                 appTransformation = wpAppAnimator.transformation;