Prevent NotificationShelf from jump cutting notifications when appearing

Even with this change, there are still issues remaining to the overall sensitive reveal animation. I'll address those in subsequent CL's.

Bug: 243634602
Flag: SENSITIVE_REVEAL_ANIM
Test: Manual, i.e. observing sensitive reveal animation when face unlocking. Also checked that the shelf is still behaving normally for other scenarios
Change-Id: I237c6e96753b0333de7ef9a3a6ae4f430788c7c2

packages/SystemUI/src/com/android/systemui/statusbar/NotificationShelf.java

@@ -98,6 +98,7 @@ public class NotificationShelf extends ActivatableNotificationView implements
     private float mCornerAnimationDistance;
     private NotificationShelfController mController;
     private float mActualWidth = -1;
+    private boolean mSensitiveRevealAnimEndabled;
 
     public NotificationShelf(Context context, AttributeSet attrs) {
         super(context, attrs);
@@ -260,7 +261,14 @@ public class NotificationShelf extends ActivatableNotificationView implements
             }
 
             final float stackEnd = ambientState.getStackY() + ambientState.getStackHeight();
-            viewState.setYTranslation(stackEnd - viewState.height);
+            if (mSensitiveRevealAnimEndabled && viewState.hidden) {
+                // if the shelf is hidden, position it at the end of the stack (plus the clip
+                // padding), such that when it appears animated, it will smoothly move in from the
+                // bottom, without jump cutting any notifications
+                viewState.setYTranslation(stackEnd + mPaddingBetweenElements);
+            } else {
+                viewState.setYTranslation(stackEnd - viewState.height);
+            }
         } else {
             viewState.hidden = true;
             viewState.location = ExpandableViewState.LOCATION_GONE;
@@ -395,7 +403,8 @@ public class NotificationShelf extends ActivatableNotificationView implements
                     expandingAnimated, isLastChild, shelfClipStart);
 
             // TODO(b/172289889) scale mPaddingBetweenElements with expansion amount
-            if ((isLastChild && !child.isInShelf()) || aboveShelf || backgroundForceHidden) {
+            if ((!mSensitiveRevealAnimEndabled && ((isLastChild && !child.isInShelf())
+                    || backgroundForceHidden)) || aboveShelf) {
                 notificationClipEnd = shelfStart + getIntrinsicHeight();
             } else {
                 notificationClipEnd = shelfStart - mPaddingBetweenElements;
@@ -437,15 +446,14 @@ public class NotificationShelf extends ActivatableNotificationView implements
             }
 
             if (child instanceof ActivatableNotificationView) {
-                ActivatableNotificationView anv =
-                        (ActivatableNotificationView) child;
+                ActivatableNotificationView anv = (ActivatableNotificationView) child;
                 // Because we show whole notifications on the lockscreen, the bottom notification is
                 // always "just about to enter the shelf" by normal scrolling rules.  This is fine
                 // if the shelf is visible, but if the shelf is hidden, it causes incorrect curling.
                 // notificationClipEnd handles the discrepancy between a visible and hidden shelf,
                 // so we use that when on the keyguard (and while animating away) to reduce curling.
-                final float keyguardSafeShelfStart =
-                        mAmbientState.isOnKeyguard() ? notificationClipEnd : shelfStart;
+                final float keyguardSafeShelfStart = !mSensitiveRevealAnimEndabled
+                        && mAmbientState.isOnKeyguard() ? notificationClipEnd : shelfStart;
                 updateCornerRoundnessOnScroll(anv, viewStart, keyguardSafeShelfStart);
             }
         }
@@ -993,6 +1001,14 @@ public class NotificationShelf extends ActivatableNotificationView implements
         mIndexOfFirstViewInShelf = mHostLayoutController.indexOfChild(firstViewInShelf);
     }
 
+    /**
+     * Set whether the sensitive reveal animation feature flag is enabled
+     * @param enabled true if enabled
+     */
+    public void setSensitiveRevealAnimEndabled(boolean enabled) {
+        mSensitiveRevealAnimEndabled = enabled;
+    }
+
     /**
      * This method resets the OnScroll roundness of a view to 0f
      * <p>

packages/SystemUI/src/com/android/systemui/statusbar/NotificationShelfController.java

@@ -55,6 +55,7 @@ public class NotificationShelfController {
         mKeyguardBypassController = keyguardBypassController;
         mStatusBarStateController = statusBarStateController;
         mView.useRoundnessSourceTypes(featureFlags.isEnabled(Flags.USE_ROUNDNESS_SOURCETYPES));
+        mView.setSensitiveRevealAnimEndabled(featureFlags.isEnabled(Flags.SENSITIVE_REVEAL_ANIM));
         mOnAttachStateChangeListener = new View.OnAttachStateChangeListener() {
             @Override
             public void onViewAttachedToWindow(View v) {