Hide footer in place instead of scrolling it offscreen

Bug: 186479647
Test: open shade with shelf,
      scroll notifications all the way up to show footer,
      then scroll down => footer hides in place
Change-Id: If95b6f8682cc1d8980d6e2b9edf769fb55aad336

1 files changed, 8 insertions, 4 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 27ee13ab4eaf..591d3c0a7a5f 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
@@ -399,10 +399,14 @@ public class StackScrollAlgorithm {
         }
 
         if (view instanceof FooterView) {
-            viewState.yTranslation = Math.min(viewState.yTranslation,
-                    ambientState.getStackHeight());
-            // Hide footer if shelf is showing
-            viewState.hidden = algorithmState.firstViewInShelf != null;
+            final boolean isShelfShowing = algorithmState.firstViewInShelf != null;
+
+            final float footerEnd = viewState.yTranslation + view.getIntrinsicHeight();
+            final boolean noSpaceForFooter = footerEnd > ambientState.getStackHeight();
+
+            viewState.hidden = isShelfShowing
+                    || (!ambientState.isExpansionChanging() && noSpaceForFooter);
+
         } else if (view != ambientState.getTrackedHeadsUpRow()) {
             if (ambientState.isExpansionChanging()) {
                 // Show all views. Views below the shelf will later be clipped (essentially hidden)