Merge "Fix empty notif view flicker on keyguard" into main

2 files changed, 23 insertions, 2 deletions

diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/StackScrollAlgorithm.java b/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/StackScrollAlgorithm.java
index e980794d23dd..d0cebae40c5a 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/StackScrollAlgorithm.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/StackScrollAlgorithm.java
@@ -169,6 +169,14 @@ public class StackScrollAlgorithm {
                 }
             }
 
+            // On the final call to {@link #resetViewState}, the alpha is set back to 1f but
+            // ambientState.isExpansionChanging() is now false. This causes a flicker on the
+            // EmptyShadeView after the shade is collapsed. Make sure the empty shade view
+            // isn't visible unless the shade is expanded.
+            if (view instanceof EmptyShadeView && ambientState.getExpansionFraction() == 0f) {
+                viewState.setAlpha(0f);
+            }
+
             // For EmptyShadeView if on keyguard, we need to control the alpha to create
             // a nice transition when the user is dragging down the notification panel.
             if (view instanceof EmptyShadeView && ambientState.isOnKeyguard()) {
diff --git a/packages/SystemUI/tests/src/com/android/systemui/statusbar/notification/stack/StackScrollAlgorithmTest.kt b/packages/SystemUI/tests/src/com/android/systemui/statusbar/notification/stack/StackScrollAlgorithmTest.kt
index 82725d656bb9..a6fb7187ff5f 100644
--- a/packages/SystemUI/tests/src/com/android/systemui/statusbar/notification/stack/StackScrollAlgorithmTest.kt
+++ b/packages/SystemUI/tests/src/com/android/systemui/statusbar/notification/stack/StackScrollAlgorithmTest.kt
@@ -394,8 +394,20 @@ class StackScrollAlgorithmTest : SysuiTestCase() {
     }
 
     @Test
+    fun resetViewStates_shadeCollapsed_emptyShadeViewBecomesTransparent() {
+        ambientState.expansionFraction = 0f
+        stackScrollAlgorithm.initView(context)
+        hostView.removeAllViews()
+        hostView.addView(emptyShadeView)
+
+        stackScrollAlgorithm.resetViewStates(ambientState, /* speedBumpIndex= */ 0)
+
+        assertThat(emptyShadeView.viewState.alpha).isEqualTo(0f)
+    }
+
+    @Test
     fun resetViewStates_isOnKeyguard_emptyShadeViewBecomesOpaque() {
-        ambientState.setStatusBarState(StatusBarState.SHADE)
+        ambientState.setStatusBarState(StatusBarState.KEYGUARD)
         ambientState.fractionToShade = 0.25f
         stackScrollAlgorithm.initView(context)
         hostView.removeAllViews()
@@ -403,7 +415,8 @@ class StackScrollAlgorithmTest : SysuiTestCase() {
 
         stackScrollAlgorithm.resetViewStates(ambientState, /* speedBumpIndex= */ 0)
 
-        assertThat(emptyShadeView.viewState.alpha).isEqualTo(1f)
+        val expected = getContentAlpha(ambientState.fractionToShade)
+        assertThat(emptyShadeView.viewState.alpha).isEqualTo(expected)
     }
 
     @Test