From f8f6deb165d1372c521f131fb4b07a35811be009 Mon Sep 17 00:00:00 2001
From: Aaron Liu <aaronjli@google.com>
Date: Fri, 18 Mar 2022 19:12:02 +0000
Subject: [PATCH] User Switcher: Prevent flickering for user switch.

There is a scrim flickering when opening activity from keyguard and from
QS in keyguard.

From Keguard, there is a flickering of the back scrim.
From QS, there is a flickering of the back scrim and the notification
scrim.

In order to prevent this, set alpha of these scrims to 0 when state is
KEYGUARD or SHADE_LOCKED

Bug: 223753460
Test: Manual on relevant devices
Change-Id: Iadf199bb5905de4d9c33e6f01a3fb20993559d25
---
 .../statusbar/phone/ScrimController.java       | 13 +++++++++++--
 .../statusbar/phone/ScrimControllerTest.java   | 18 ++++++++++++++++++
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/phone/ScrimController.java b/packages/SystemUI/src/com/android/systemui/statusbar/phone/ScrimController.java
index 0b95458b73df7..28f2e61bd8c6a 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/phone/ScrimController.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/phone/ScrimController.java
@@ -1021,15 +1021,24 @@ public class ScrimController implements ViewTreeObserver.OnPreDrawListener, Dump
         boolean aodWallpaperTimeout = (mState == ScrimState.AOD || mState == ScrimState.PULSING)
                 && mWallpaperVisibilityTimedOut;
         // We also want to hide FLAG_SHOW_WHEN_LOCKED activities under the scrim.
-        boolean occludedKeyguard = (mState == ScrimState.PULSING || mState == ScrimState.AOD)
+        boolean hideFlagShowWhenLockedActivities =
+                (mState == ScrimState.PULSING || mState == ScrimState.AOD)
                 && mKeyguardOccluded;
-        if (aodWallpaperTimeout || occludedKeyguard) {
+        if (aodWallpaperTimeout || hideFlagShowWhenLockedActivities) {
             mBehindAlpha = 1;
         }
         // Prevent notification scrim flicker when transitioning away from keyguard.
         if (mKeyguardStateController.isKeyguardGoingAway()) {
             mNotificationsAlpha = 0;
         }
+
+        // Prevent flickering for activities above keyguard and quick settings in keyguard.
+        if (mKeyguardOccluded
+                && (mState == ScrimState.KEYGUARD || mState == ScrimState.SHADE_LOCKED)) {
+            mBehindAlpha = 0;
+            mNotificationsAlpha = 0;
+        }
+
         setScrimAlpha(mScrimInFront, mInFrontAlpha);
         setScrimAlpha(mScrimBehind, mBehindAlpha);
         setScrimAlpha(mNotificationsScrim, mNotificationsAlpha);
diff --git a/packages/SystemUI/tests/src/com/android/systemui/statusbar/phone/ScrimControllerTest.java b/packages/SystemUI/tests/src/com/android/systemui/statusbar/phone/ScrimControllerTest.java
index b3f8f9114021e..4563239f80541 100644
--- a/packages/SystemUI/tests/src/com/android/systemui/statusbar/phone/ScrimControllerTest.java
+++ b/packages/SystemUI/tests/src/com/android/systemui/statusbar/phone/ScrimControllerTest.java
@@ -1383,6 +1383,24 @@ public class ScrimControllerTest extends SysuiTestCase {
                 .isEqualTo(ScrimState.KEYGUARD.getBehindTint());
     }
 
+    @Test
+    public void testHidesScrimFlickerInActivity() {
+        mScrimController.setKeyguardOccluded(true);
+        mScrimController.transitionTo(ScrimState.KEYGUARD);
+        finishAnimationsImmediately();
+        assertScrimAlpha(Map.of(
+                mScrimInFront, TRANSPARENT,
+                mScrimBehind, TRANSPARENT,
+                mNotificationsScrim, TRANSPARENT));
+
+        mScrimController.transitionTo(ScrimState.SHADE_LOCKED);
+        finishAnimationsImmediately();
+        assertScrimAlpha(Map.of(
+                mScrimInFront, TRANSPARENT,
+                mScrimBehind, TRANSPARENT,
+                mNotificationsScrim, TRANSPARENT));
+    }
+
     private void assertAlphaAfterExpansion(ScrimView scrim, float expectedAlpha, float expansion) {
         mScrimController.setRawPanelExpansionFraction(expansion);
         finishAnimationsImmediately();