Merge "Fix z-order of displays when adjusting position of stack"

2 files changed, 30 insertions, 0 deletions

diff --git a/services/core/java/com/android/server/wm/DisplayContent.java b/services/core/java/com/android/server/wm/DisplayContent.java
index 5d0101f88c69..ac6582634bf8 100644
--- a/services/core/java/com/android/server/wm/DisplayContent.java
+++ b/services/core/java/com/android/server/wm/DisplayContent.java
@@ -3606,6 +3606,18 @@ class DisplayContent extends WindowContainer<DisplayContent.DisplayChildWindowCo
             final int targetPosition = findPositionForStack(position, child, false /* adding */);
             super.positionChildAt(targetPosition, child, includingParents);
 
+            if (includingParents) {
+                // We still want to move the display of this stack container to top because even the
+                // target position is adjusted to non-top, the intention of the condition is to have
+                // higher z-order to gain focus (e.g. moving a task of a fullscreen stack to front
+                // in a non-top display which is using picture-in-picture mode).
+                final int topChildPosition = getChildCount() - 1;
+                if (targetPosition < topChildPosition && position >= topChildPosition) {
+                    getParent().positionChildAt(POSITION_TOP, this /* child */,
+                            true /* includingParents */);
+                }
+            }
+
             setLayoutNeeded();
         }
 
diff --git a/services/tests/servicestests/src/com/android/server/wm/TaskStackContainersTests.java b/services/tests/servicestests/src/com/android/server/wm/TaskStackContainersTests.java
index 9fa5ba42204f..ea44279b46a9 100644
--- a/services/tests/servicestests/src/com/android/server/wm/TaskStackContainersTests.java
+++ b/services/tests/servicestests/src/com/android/server/wm/TaskStackContainersTests.java
@@ -109,4 +109,22 @@ public class TaskStackContainersTests extends WindowTestsBase {
         assertEquals(taskStackContainer.mChildren.get(stackPos), stack1);
         assertEquals(taskStackContainer.mChildren.get(pinnedStackPos), mPinnedStack);
     }
+
+    @Test
+    public void testDisplayPositionWithPinnedStack() {
+        // The display contains pinned stack that was added in {@link #setUp}.
+        final TaskStack stack = createTaskStackOnDisplay(mDisplayContent);
+        final Task task = createTaskInStack(stack, 0 /* userId */);
+
+        // Add another display at top.
+        sWm.mRoot.positionChildAt(WindowContainer.POSITION_TOP, createNewDisplay(),
+                false /* includingParents */);
+
+        // Move the task of {@code mDisplayContent} to top.
+        stack.positionChildAt(WindowContainer.POSITION_TOP, task, true /* includingParents */);
+        final int indexOfDisplayWithPinnedStack = sWm.mRoot.mChildren.indexOf(mDisplayContent);
+
+        assertEquals("The testing DisplayContent should be moved to top with task",
+                sWm.mRoot.getChildCount() - 1, indexOfDisplayWithPinnedStack);
+    }
 }