From e31d74b1162fd8921fad32e20de87daba419bb07 Mon Sep 17 00:00:00 2001
From: Taran Singh <tarandeep@google.com>
Date: Fri, 21 May 2021 19:19:12 +0000
Subject: [PATCH] Fix IME flicker to home screen w/ orientation change

In [1] we attempted to updateImeParent() onConfigurationChange(),
computeImeParent() can pick a parent that didnt even request IME.
This can cause flicker when going from app to launcher.

Adding a check for prevents this from happening.

Fix: 188864578
Test: atest DisplayContentTests

Change-Id: I01b67b9a7fdf04f23ab05c244281f42518352ca5
---
 .../com/android/server/wm/DisplayContent.java    |  4 ++++
 .../android/server/wm/DisplayContentTests.java   | 16 ++++++++++++++++
 2 files changed, 20 insertions(+)

diff --git a/services/core/java/com/android/server/wm/DisplayContent.java b/services/core/java/com/android/server/wm/DisplayContent.java
index 1ec07d047e13f..bbf474c3eaa97 100644
--- a/services/core/java/com/android/server/wm/DisplayContent.java
+++ b/services/core/java/com/android/server/wm/DisplayContent.java
@@ -3963,6 +3963,10 @@ class DisplayContent extends RootDisplayArea implements WindowManagerPolicy.Disp
         // screen. If it's not covering the entire screen the IME might extend beyond the apps
         // bounds.
         if (allowAttachToApp && shouldImeAttachedToApp()) {
+            if (mImeLayeringTarget.mActivityRecord != mImeInputTarget.mActivityRecord) {
+                // Do not change parent if the window hasn't requested IME.
+                return null;
+            }
             return mImeLayeringTarget.mActivityRecord.getSurfaceControl();
         }
 
diff --git a/services/tests/wmtests/src/com/android/server/wm/DisplayContentTests.java b/services/tests/wmtests/src/com/android/server/wm/DisplayContentTests.java
index 6d4454bd964a9..e569376b7cce7 100644
--- a/services/tests/wmtests/src/com/android/server/wm/DisplayContentTests.java
+++ b/services/tests/wmtests/src/com/android/server/wm/DisplayContentTests.java
@@ -357,6 +357,22 @@ public class DisplayContentTests extends WindowTestsBase {
         verify(imeContainer).assignRelativeLayer(any(), eq(imeSurfaceParent), anyInt(), eq(true));
     }
 
+    @Test
+    public void testComputeImeTargetReturnsNull_windowDidntRequestIme() {
+        final WindowState win1 = createWindow(null, TYPE_BASE_APPLICATION,
+                new ActivityBuilder(mAtm).setCreateTask(true).build(), "app");
+        final WindowState win2 = createWindow(null, TYPE_BASE_APPLICATION,
+                new ActivityBuilder(mAtm).setCreateTask(true).build(), "app2");
+
+        mDisplayContent.setImeInputTarget(win1);
+        mDisplayContent.setImeLayeringTarget(win2);
+
+        doReturn(true).when(mDisplayContent).shouldImeAttachedToApp();
+        // Compute IME parent returns nothing if current target and window receiving input
+        // are different i.e. if current window didn't request IME.
+        assertNull("computeImeParent() should be null", mDisplayContent.computeImeParent());
+    }
+
     /**
      * This tests root task movement between displays and proper root task's, task's and app token's
      * display container references updates.