Move home task behind visible task

When switching to desktop mode, move home task behind visible task(s).
This ensures that only the visible task is shown at first on the
desktop.

Bug: 258282673
Test: atest DesktopModeControllerTest
Change-Id: I1d593900789846d8389decaddbaf92eb4a1d6e87

2 files changed, 56 insertions, 5 deletions

diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/desktopmode/DesktopModeController.java b/libs/WindowManager/Shell/src/com/android/wm/shell/desktopmode/DesktopModeController.java
index f0255a335d5e..abc4024bc290 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/desktopmode/DesktopModeController.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/desktopmode/DesktopModeController.java
@@ -16,6 +16,7 @@
 
 package com.android.wm.shell.desktopmode;
 
+import static android.app.WindowConfiguration.ACTIVITY_TYPE_HOME;
 import static android.app.WindowConfiguration.ACTIVITY_TYPE_STANDARD;
 import static android.app.WindowConfiguration.WINDOWING_MODE_FREEFORM;
 import static android.app.WindowConfiguration.WINDOWING_MODE_FULLSCREEN;
@@ -158,15 +159,13 @@ public class DesktopModeController implements RemoteCallable<DesktopModeControll
         WindowContainerTransaction wct = new WindowContainerTransaction();
         // Reset freeform windowing mode that is set per task level so tasks inherit it
         clearFreeformForStandardTasks(runningTasks, wct);
-        int targetWindowingMode;
         if (active) {
-            targetWindowingMode = WINDOWING_MODE_FREEFORM;
+            moveHomeBehindVisibleTasks(runningTasks, wct);
+            setDisplayAreaWindowingMode(displayId, WINDOWING_MODE_FREEFORM, wct);
         } else {
-            targetWindowingMode = WINDOWING_MODE_FULLSCREEN;
-            // Clear any resized bounds
             clearBoundsForStandardTasks(runningTasks, wct);
+            setDisplayAreaWindowingMode(displayId, WINDOWING_MODE_FULLSCREEN, wct);
         }
-        setDisplayAreaWindowingMode(displayId, targetWindowingMode, wct);
         if (Transitions.ENABLE_SHELL_TRANSITIONS) {
             mTransitions.startTransition(TRANSIT_CHANGE, wct, null);
         } else {
@@ -201,6 +200,31 @@ public class DesktopModeController implements RemoteCallable<DesktopModeControll
         }
     }
 
+    private void moveHomeBehindVisibleTasks(ArrayList<RunningTaskInfo> runningTasks,
+            WindowContainerTransaction wct) {
+        ProtoLog.v(WM_SHELL_DESKTOP_MODE, "moveHomeBehindVisibleTasks");
+        RunningTaskInfo homeTask = null;
+        ArrayList<RunningTaskInfo> visibleTasks = new ArrayList<>();
+        for (RunningTaskInfo taskInfo : runningTasks) {
+            if (taskInfo.getActivityType() == ACTIVITY_TYPE_HOME) {
+                homeTask = taskInfo;
+            } else if (taskInfo.getActivityType() == ACTIVITY_TYPE_STANDARD
+                    && taskInfo.isVisible()) {
+                visibleTasks.add(taskInfo);
+            }
+        }
+        if (homeTask == null) {
+            ProtoLog.w(WM_SHELL_DESKTOP_MODE, "moveHomeBehindVisibleTasks: home task not found");
+        } else {
+            ProtoLog.v(WM_SHELL_DESKTOP_MODE, "moveHomeBehindVisibleTasks: visible tasks %d",
+                    visibleTasks.size());
+            wct.reorder(homeTask.getToken(), true /* onTop */);
+            for (RunningTaskInfo task : visibleTasks) {
+                wct.reorder(task.getToken(), true /* onTop */);
+            }
+        }
+    }
+
     private void setDisplayAreaWindowingMode(int displayId,
             @WindowConfiguration.WindowingMode int windowingMode, WindowContainerTransaction wct) {
         DisplayAreaInfo displayAreaInfo = mRootTaskDisplayAreaOrganizer.getDisplayAreaInfo(
diff --git a/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/desktopmode/DesktopModeControllerTest.java b/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/desktopmode/DesktopModeControllerTest.java
index 528b26ec2362..89bafcb6b2f4 100644
--- a/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/desktopmode/DesktopModeControllerTest.java
+++ b/libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/desktopmode/DesktopModeControllerTest.java
@@ -206,6 +206,33 @@ public class DesktopModeControllerTest extends ShellTestCase {
     }
 
     @Test
+    public void testDesktopModeEnabled_homeTaskBehindVisibleTask() {
+        createMockDisplayArea();
+        RunningTaskInfo fullscreenTask1 = createFullscreenTask();
+        fullscreenTask1.isVisible = true;
+        RunningTaskInfo fullscreenTask2 = createFullscreenTask();
+        fullscreenTask2.isVisible = false;
+        RunningTaskInfo homeTask = createHomeTask();
+        when(mShellTaskOrganizer.getRunningTasks(anyInt())).thenReturn(new ArrayList<>(
+                Arrays.asList(fullscreenTask1, fullscreenTask2, homeTask)));
+
+        mController.updateDesktopModeActive(true);
+        WindowContainerTransaction wct = getDesktopModeSwitchTransaction();
+
+        // Check that there are hierarchy changes for home task and visible task
+        assertThat(wct.getHierarchyOps()).hasSize(2);
+        // First show home task
+        WindowContainerTransaction.HierarchyOp op1 = wct.getHierarchyOps().get(0);
+        assertThat(op1.getType()).isEqualTo(HIERARCHY_OP_TYPE_REORDER);
+        assertThat(op1.getContainer()).isEqualTo(homeTask.token.asBinder());
+
+        // Then visible task on top of it
+        WindowContainerTransaction.HierarchyOp op2 = wct.getHierarchyOps().get(1);
+        assertThat(op2.getType()).isEqualTo(HIERARCHY_OP_TYPE_REORDER);
+        assertThat(op2.getContainer()).isEqualTo(fullscreenTask1.token.asBinder());
+    }
+
+    @Test
     public void testShowDesktopApps() {
         // Set up two active tasks on desktop
         RunningTaskInfo freeformTask1 = createFreeformTask();