From 7087a7bd91c8c136722b6b515568f1c9f0aa1f46 Mon Sep 17 00:00:00 2001
From: Tracy Zhou <tracyzhou@google.com>
Date: Tue, 12 May 2020 21:34:13 -0700
Subject: [PATCH] Don't continue rendering preview screen when binder is dead

Fixes: 155365052
Test: manually quick switches between different grid options
Change-Id: I31dc14b0a50b5e3a5c81272b693303034fcf8b40
---
 .../graphics/PreviewSurfaceRenderer.java      | 22 ++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/src/com/android/launcher3/graphics/PreviewSurfaceRenderer.java b/src/com/android/launcher3/graphics/PreviewSurfaceRenderer.java
index c62f308367..350f221c97 100644
--- a/src/com/android/launcher3/graphics/PreviewSurfaceRenderer.java
+++ b/src/com/android/launcher3/graphics/PreviewSurfaceRenderer.java
@@ -81,10 +81,12 @@ public class PreviewSurfaceRenderer implements IBinder.DeathRecipient {
             binderDied();
         }
 
+        SurfaceControlViewHost.SurfacePackage surfacePackage;
         try {
             mSurfaceControlViewHost = MAIN_EXECUTOR
                     .submit(() -> new SurfaceControlViewHost(mContext, mDisplay, mHostToken))
                     .get(5, TimeUnit.SECONDS);
+            surfacePackage = mSurfaceControlViewHost.getSurfacePackage();
             mHostToken.linkToDeath(this, 0);
         } catch (Exception e) {
             e.printStackTrace();
@@ -92,6 +94,14 @@ public class PreviewSurfaceRenderer implements IBinder.DeathRecipient {
         }
 
         MAIN_EXECUTOR.execute(() -> {
+            // If mSurfaceControlViewHost is null due to any reason (e.g. binder died,
+            // happening when user leaves the preview screen before preview rendering finishes),
+            // we should return here.
+            SurfaceControlViewHost host = mSurfaceControlViewHost;
+            if (host == null) {
+                return;
+            }
+
             View view = new LauncherPreviewRenderer(mContext, mIdp).getRenderedView();
             // This aspect scales the view to fit in the surface and centers it
             final float scale = Math.min(mWidth / (float) view.getMeasuredWidth(),
@@ -107,14 +117,14 @@ public class PreviewSurfaceRenderer implements IBinder.DeathRecipient {
                     .setInterpolator(new AccelerateDecelerateInterpolator())
                     .setDuration(FADE_IN_ANIMATION_DURATION)
                     .start();
-            mSurfaceControlViewHost.setView(view, view.getMeasuredWidth(),
+            host.setView(view, view.getMeasuredWidth(),
                     view.getMeasuredHeight());
         });
 
         Bundle result = new Bundle();
-        result.putParcelable(KEY_SURFACE_PACKAGE, mSurfaceControlViewHost.getSurfacePackage());
+        result.putParcelable(KEY_SURFACE_PACKAGE, surfacePackage);
 
-        Handler handler = new Handler(Looper.getMainLooper(), Loopermessage -> {
+        Handler handler = new Handler(Looper.getMainLooper(), message -> {
             binderDied();
             return true;
         });
@@ -128,8 +138,10 @@ public class PreviewSurfaceRenderer implements IBinder.DeathRecipient {
     @Override
     public void binderDied() {
         if (mSurfaceControlViewHost != null) {
-            mSurfaceControlViewHost.release();
-            mSurfaceControlViewHost = null;
+            MAIN_EXECUTOR.execute(() -> {
+                mSurfaceControlViewHost.release();
+                mSurfaceControlViewHost = null;
+            });
         }
         mHostToken.unlinkToDeath(this, 0);
     }