From 21d857a21f36ac17faf613c7547e7a913697d045 Mon Sep 17 00:00:00 2001
From: Andy Wickham <awickham@google.com>
Date: Mon, 10 Apr 2023 19:02:44 -0700
Subject: [PATCH] Fix single frame flicker for views reacting to keyboard
 insets.

This includes Folders, bottom apps searchbar, work apps button.

The issue is that the view was being drawn between onStart and
onProgress. Before onStart is called, the final keyboard insets
are dispatched to determine the view's final state, so this draw
captured this otherwise invisible state. Normally, onProgress
would be called first, effectively resetting the view; but for
example, the transition from closing the apps drawer forces a
draw prematurely.

Fix: 265830720
Test: Manual
Flag: N/A, but improves the ENABLE_FLOATING_SEARCH_BAR flag.
Change-Id: I818cb75628dec6dcc69e5f4b8ae554c2245dceca
---
 .../anim/KeyboardInsetAnimationCallback.java  | 34 ++++++++++++-------
 1 file changed, 22 insertions(+), 12 deletions(-)

diff --git a/src/com/android/launcher3/anim/KeyboardInsetAnimationCallback.java b/src/com/android/launcher3/anim/KeyboardInsetAnimationCallback.java
index 3863dc1962..b911928e36 100644
--- a/src/com/android/launcher3/anim/KeyboardInsetAnimationCallback.java
+++ b/src/com/android/launcher3/anim/KeyboardInsetAnimationCallback.java
@@ -27,7 +27,16 @@ import com.android.launcher3.Utilities;
 import java.util.List;
 
 /**
- * Callback that animates views above the IME
+ * Callback that animates views above the IME.
+ * <p>
+ * The expected stages of a keyboard transition are:
+ * <p>
+ * <ul>
+ *   <li>PREPARING: Keyboard insets haven't changed yet, but are about to.</li>
+ *   <li>STARTED: Keyboard insets have temporarily changed to the end state, but not drawn.</li>
+ *   <li>PROGRESSING: At least one frame of the animation has been drawn.</li>
+ *   <li>FINISHED: Keyboard has reached its end state, and animation is complete.</li>
+ * </ul>
  */
 @RequiresApi(api = Build.VERSION_CODES.R)
 public class KeyboardInsetAnimationCallback extends WindowInsetsAnimation.Callback {
@@ -46,6 +55,18 @@ public class KeyboardInsetAnimationCallback extends WindowInsetsAnimation.Callba
         mInitialTranslation = mView.getTranslationY();
     }
 
+    @Override
+    public WindowInsetsAnimation.Bounds onStart(WindowInsetsAnimation animation,
+            WindowInsetsAnimation.Bounds bounds) {
+        // Final insets have temporarily been applied, so store the current translation as final.
+        mTerminalTranslation = mView.getTranslationY();
+        // Reset the translation in case the view is drawn before onProgress gets called.
+        mView.setTranslationY(mInitialTranslation);
+        if (mView instanceof KeyboardInsetListener) {
+            ((KeyboardInsetListener) mView).onTranslationStart();
+        }
+        return super.onStart(animation, bounds);
+    }
 
     @Override
     public WindowInsets onProgress(WindowInsets windowInsets, List<WindowInsetsAnimation> list) {
@@ -72,19 +93,8 @@ public class KeyboardInsetAnimationCallback extends WindowInsetsAnimation.Callba
         return windowInsets;
     }
 
-    @Override
-    public WindowInsetsAnimation.Bounds onStart(WindowInsetsAnimation animation,
-            WindowInsetsAnimation.Bounds bounds) {
-        mTerminalTranslation = mView.getTranslationY();
-        if (mView instanceof KeyboardInsetListener) {
-            ((KeyboardInsetListener) mView).onTranslationStart();
-        }
-        return super.onStart(animation, bounds);
-    }
-
     @Override
     public void onEnd(WindowInsetsAnimation animation) {
-        mView.setTranslationY(mTerminalTranslation);
         if (mView instanceof KeyboardInsetListener) {
             ((KeyboardInsetListener) mView).onTranslationEnd();
         }