From c06432da47bda910bbd87171a84ec7055128800b Mon Sep 17 00:00:00 2001
From: amirh <amirh@users.noreply.github.com>
Date: Mon, 20 Aug 2018 12:13:26 -0700
Subject: [PATCH] Delay the removal of the onDrawListener. (#6052)

In Android O removing the ViewTreeObserver.onDrawListener from the
listener call crashes. Instead we post a runnable to remove it.
---
 .../platform/VirtualDisplayController.java    | 37 +++++++++++++++++--
 1 file changed, 34 insertions(+), 3 deletions(-)

diff --git a/shell/platform/android/io/flutter/plugin/platform/VirtualDisplayController.java b/shell/platform/android/io/flutter/plugin/platform/VirtualDisplayController.java
index 2e062f8c2..656246cf5 100644
--- a/shell/platform/android/io/flutter/plugin/platform/VirtualDisplayController.java
+++ b/shell/platform/android/io/flutter/plugin/platform/VirtualDisplayController.java
@@ -98,9 +98,9 @@ class VirtualDisplayController {
         embeddedView.addOnAttachStateChangeListener(new View.OnAttachStateChangeListener() {
             @Override
             public void onViewAttachedToWindow(View v) {
-                embeddedView.getViewTreeObserver().addOnDrawListener(new ViewTreeObserver.OnDrawListener() {
+                OneTimeOnDrawListener.schedule(embeddedView, new Runnable() {
                     @Override
-                    public void onDraw() {
+                    public void run() {
                         // We need some delay here until the frame propagates through the vd surface to to the texture,
                         // 128ms was picked pretty arbitrarily based on trial and error.
                         // As long as we invoke the runnable after a new frame is available we avoid the scaling jank
@@ -108,7 +108,6 @@ class VirtualDisplayController {
                         // We should ideally run onNewSizeFrameAvailable ASAP to make the embedded view more responsive
                         // following a resize.
                         embeddedView.postDelayed(onNewSizeFrameAvailable, 128);
-                        embeddedView.getViewTreeObserver().removeOnDrawListener(this);
                     }
                 });
                 embeddedView.removeOnAttachStateChangeListener(this);
@@ -135,4 +134,36 @@ class VirtualDisplayController {
         PlatformView platformView = mPresentation.getView();
         return platformView.getView();
     }
+
+    @TargetApi(Build.VERSION_CODES.JELLY_BEAN)
+    static class OneTimeOnDrawListener implements ViewTreeObserver.OnDrawListener {
+        static void schedule(View view, Runnable runnable) {
+            OneTimeOnDrawListener listener = new OneTimeOnDrawListener(view, runnable);
+            view.getViewTreeObserver().addOnDrawListener(listener);
+        }
+
+        final View mView;
+        Runnable mOnDrawRunnable;
+
+        OneTimeOnDrawListener(View view, Runnable onDrawRunnable) {
+            this.mView = view;
+            this.mOnDrawRunnable = onDrawRunnable;
+        }
+
+        @Override
+        public void onDraw() {
+            if (mOnDrawRunnable == null) {
+                return;
+            }
+            mOnDrawRunnable.run();
+            mOnDrawRunnable = null;
+            mView.post(new Runnable() {
+                @Override
+                public void run() {
+                    mView.getViewTreeObserver().removeOnDrawListener(OneTimeOnDrawListener.this);
+                }
+            });
+        }
+    }
 }
+
-- 
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