From 280cb21137da953ab3a8acae08ea33a4d381bb10 Mon Sep 17 00:00:00 2001
From: lumark <lumark@google.com>
Date: Mon, 9 Sep 2019 09:47:22 +0800
Subject: [PATCH] Make sure to clear previous display's last focus window when
 reparenting task

This CL is to fix IME can't show up on reparented task in auto device with per-display
focus enabled.

When reparenting task from display A to display B, if the current display focus from
display of the task changed to another display (i.e. received a pointer outside touch),

It made in DisplayContent#reParentWindowToken logic won't clear prevDc#mLastFocus
(the reparent task's window in previous display), since mCurrentFocus
(the target display's window) is not the same as prevDc#mLastFocus during reparent,
caused the client side will end up receive window focus lost change (this issue won't
happen w/o per-display focus, since prevDc#mLastFocus will always null due to only
single focus window), so IME can't show up when tapping the EditText of the reparented
task.

The fix is to consolide clear prevDc#mLastFocus check, if last focused window of
previous display is contained in a reparented window token, which means
the reparent task will end up to gain window focus on the target display & won't need to
receive focus lost event from previous display & the state should be cleared.

Bug: 136503036
Test: atest MultiDisplaySystemDecorationTests#testImeWindowCanShownWhenActivityMovedToDisplay
Change-Id: Ifd5b7bbf381440c302194c9efff595bf51b5b42b
---
 .../core/java/com/android/server/wm/DisplayContent.java    | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/services/core/java/com/android/server/wm/DisplayContent.java b/services/core/java/com/android/server/wm/DisplayContent.java
index e099a4f0c91c8..bafb0d1e26a4e 100644
--- a/services/core/java/com/android/server/wm/DisplayContent.java
+++ b/services/core/java/com/android/server/wm/DisplayContent.java
@@ -1072,9 +1072,10 @@ class DisplayContent extends WindowContainer<DisplayContent.DisplayChildWindowCo
                 // removing from parent.
                 token.getParent().removeChild(token);
             }
-            if (prevDc.mLastFocus == mCurrentFocus) {
-                // The window has become the focus of this display, so it should not be notified
-                // that it lost focus from the previous display.
+            if (token.hasChild(prevDc.mLastFocus)) {
+                // If the reparent window token contains previous display's last focus window, means
+                // it will end up to gain window focus on the target display, so it should not be
+                // notified that it lost focus from the previous display.
                 prevDc.mLastFocus = null;
             }
         }