From a8535e9ae6d86ffbc5ec717f849321345de585e3 Mon Sep 17 00:00:00 2001
From: Lyn Han <lynhan@google.com>
Date: Tue, 8 Feb 2022 12:36:02 -0600
Subject: Fix bug where shade is infinitely squishy after wallpaper change

This change fixes a bug where
opening an empty shade after wallpaper update
=> messes up qs button unfurling
=> hides the "no notifications" text

This bug happened because
=> wallpaper change causes theme change
=> on theme change, NSSLC reinflates EmptyShadeView
   with visibility=false
=> nothing resets EmptyShadeView visiblity=true on shade open
=> AmbientState has 0 visibleChildren during shade open,
   so stackHeight is 0 and expansionFraction is infinity

The solution is to have NSSLC
update EmptyShadeView visibility after re-inflation.

Fixes: 215038354
Fixes: 218501868
Fixes: 218380326
Test: have no notifications, change wallpaper, open shade
     => qs button squishiness animates fine
     => "no notifications" text shows up fine
     => log squishiness: no infinity or NaN

Change-Id: Iaa10605079db7edc79771a1cd9f4cc17f847c4cb
(cherry picked from commit d2adae5b5d8a1b6a77386cc7eaf98dafe4b43ce4)
(cherry picked from commit cf293657bf6520ea04f0c5eab493ad06f1f472f5)
Merged-In:Iaa10605079db7edc79771a1cd9f4cc17f847c4cb
---
 .../notification/stack/NotificationStackScrollLayoutController.java  | 2 +-
 .../systemui/statusbar/notification/stack/StackScrollAlgorithm.java  | 5 +++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/NotificationStackScrollLayoutController.java b/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/NotificationStackScrollLayoutController.java
index f14cc93c2046..9f440606a365 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/NotificationStackScrollLayoutController.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/NotificationStackScrollLayoutController.java
@@ -279,11 +279,11 @@ public class NotificationStackScrollLayoutController {
 
         @Override
         public void onThemeChanged() {
-            updateShowEmptyShadeView();
             mView.updateCornerRadius();
             mView.updateBgColor();
             mView.updateDecorViews();
             mView.reinflateViews();
+            updateShowEmptyShadeView();
             updateFooter();
         }
 
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 2c70a5fd9ce7..c4567df914f0 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
@@ -376,6 +376,11 @@ public class StackScrollAlgorithm {
 
         final float stackHeight = ambientState.getStackHeight()  - shelfHeight - scrimPadding;
         final float stackEndHeight = ambientState.getStackEndHeight() - shelfHeight - scrimPadding;
+        if (stackEndHeight == 0f) {
+            // This should not happen, since even when the shade is empty we show EmptyShadeView
+            // but check just in case, so we don't return infinity or NaN.
+            return 0f;
+        }
         return stackHeight / stackEndHeight;
     }
 
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