From c9654eb09158a9878d7ff8fc9e588ec2d4903318 Mon Sep 17 00:00:00 2001
From: Tony Wickham <twickham@google.com>
Date: Tue, 1 Oct 2019 10:03:14 -0700
Subject: [PATCH] Don't allow scrolling RecentsView outside navbar during
 quickswitch

Once the inputProxy (OverviewInputConsumer) was enabled, it was never
disabled. And while it was enabled, touches above the nav bar would go
through to launcher, allowing you to scroll RecentsView (for example)
during quick switch transitions. This breaks some assumptions, since
it doesn't go through our normal shared swipe state logic that cancels
the animation, updates the new end target (e.g. NEW_TASK vs LAST_TASK),
etc. Thus, if you tried returning to LAST_TASK via this route, we would
end up starting it as a new activity instead of resuming the existing
one, causing a flicker (I guess because that TaskView is hidden).

Test:
- Swipe up from task A to home (to enable input proxy)
- Open A
- Swipe to B, and during transition scroll back to A from the center of
the screen

Before, this caused a flicker, now the last scroll is ignored.

TODO: we should increase the nav region during quick switch to make it
easier to continue scrolling

Bug: 136829198
Bug: 138620399
Change-Id: I5ffb53743b728e1909066c5dd18cc9308aff2c7e
---
 .../quickstep/RecentsAnimationWrapper.java    | 27 +++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/quickstep/recents_ui_overrides/src/com/android/quickstep/RecentsAnimationWrapper.java b/quickstep/recents_ui_overrides/src/com/android/quickstep/RecentsAnimationWrapper.java
index e51ba631bf..c4d3fa03aa 100644
--- a/quickstep/recents_ui_overrides/src/com/android/quickstep/RecentsAnimationWrapper.java
+++ b/quickstep/recents_ui_overrides/src/com/android/quickstep/RecentsAnimationWrapper.java
@@ -19,6 +19,8 @@ import static android.view.MotionEvent.ACTION_CANCEL;
 import static android.view.MotionEvent.ACTION_DOWN;
 import static android.view.MotionEvent.ACTION_UP;
 
+import android.os.SystemClock;
+import android.util.Log;
 import android.view.InputEvent;
 import android.view.KeyEvent;
 import android.view.MotionEvent;
@@ -38,6 +40,8 @@ import java.util.function.Supplier;
  */
 public class RecentsAnimationWrapper {
 
+    private static final String TAG = "RecentsAnimationWrapper";
+
     // A list of callbacks to run when we receive the recents animation target. There are different
     // than the state callbacks as these run on the current worker thread.
     private final ArrayList<Runnable> mCallbacks = new ArrayList<>();
@@ -125,6 +129,7 @@ public class RecentsAnimationWrapper {
             boolean sendUserLeaveHint) {
         SwipeAnimationTargetSet controller = targetSet;
         targetSet = null;
+        disableInputProxy();
         if (controller != null) {
             controller.finishController(toRecents, onFinishComplete, sendUserLeaveHint);
         }
@@ -153,6 +158,16 @@ public class RecentsAnimationWrapper {
         mInputConsumerController.setInputListener(this::onInputConsumerEvent);
     }
 
+    private void disableInputProxy() {
+        if (mInputConsumer != null && mTouchInProgress) {
+            long now = SystemClock.uptimeMillis();
+            MotionEvent dummyCancel = MotionEvent.obtain(now,  now, ACTION_CANCEL, 0, 0, 0);
+            mInputConsumer.onMotionEvent(dummyCancel);
+            dummyCancel.recycle();
+        }
+        mInputConsumerController.setInputListener(null);
+    }
+
     private boolean onInputConsumerEvent(InputEvent ev) {
         if (ev instanceof MotionEvent) {
             onInputConsumerMotionEvent((MotionEvent) ev);
@@ -168,6 +183,18 @@ public class RecentsAnimationWrapper {
 
     private boolean onInputConsumerMotionEvent(MotionEvent ev) {
         int action = ev.getAction();
+
+        // Just to be safe, verify that ACTION_DOWN comes before any other action,
+        // and ignore any ACTION_DOWN after the first one (though that should not happen).
+        if (!mTouchInProgress && action != ACTION_DOWN) {
+            Log.w(TAG, "Received non-down motion before down motion: " + action);
+            return false;
+        }
+        if (mTouchInProgress && action == ACTION_DOWN) {
+            Log.w(TAG, "Received down motion while touch was already in progress");
+            return false;
+        }
+
         if (action == ACTION_DOWN) {
             mTouchInProgress = true;
             if (mInputConsumer == null) {