Push wallpapers on the back during transitions

Fix: 350617801
Test: Manual, verify wallpaper stays on the back when opening app pair
Test: Manual, unlock device with separate lock/home  wallpapers
Flag: com.android.window.flags.ensure_wallpaper_in_transitions
Change-Id: Ie6bd4d18bfe67ca27b791a666d5b0bff6199773c

1 files changed, 9 insertions, 0 deletions

diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/transition/Transitions.java b/libs/WindowManager/Shell/src/com/android/wm/shell/transition/Transitions.java
index ec6802da85f6..3e6ac95a4fed 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/transition/Transitions.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/transition/Transitions.java
@@ -76,6 +76,7 @@ import androidx.annotation.BinderThread;
 import com.android.internal.R;
 import com.android.internal.annotations.VisibleForTesting;
 import com.android.internal.protolog.ProtoLog;
+import com.android.window.flags.Flags;
 import com.android.wm.shell.RootTaskDisplayAreaOrganizer;
 import com.android.wm.shell.ShellTaskOrganizer;
 import com.android.wm.shell.common.DisplayController;
@@ -585,6 +586,14 @@ public class Transitions implements RemoteCallable<Transitions>,
         final boolean isOpening = isOpeningType(transitType);
         final boolean isClosing = isClosingType(transitType);
         final int mode = change.getMode();
+        // Ensure wallpapers stay in the back
+        if (change.hasFlags(FLAG_IS_WALLPAPER) && Flags.ensureWallpaperInTransitions()) {
+            if (mode == TRANSIT_OPEN || mode == TRANSIT_TO_FRONT) {
+                return -zSplitLine + numChanges - i;
+            } else {
+                return -zSplitLine - i;
+            }
+        }
         // Put all the OPEN/SHOW on top
         if (mode == TRANSIT_OPEN || mode == TRANSIT_TO_FRONT) {
             if (isOpening) {