From 3c089996dcf45bdb15d51d2bc09d8024ee74c5d4 Mon Sep 17 00:00:00 2001
From: Jason Simmons <jason-simmons@users.noreply.github.com>
Date: Thu, 2 Apr 2020 18:16:05 -0700
Subject: [PATCH] Disconnect from platform views and virtual displays before
 detaching from the engine (flutter/engine#17379)

---
 .../io/flutter/app/FlutterPluginRegistry.java |  4 ++--
 .../embedding/engine/FlutterEngine.java       |  2 ++
 .../platform/PlatformViewsController.java     | 16 +++++++++++++-
 .../embedding/engine/FlutterEngineTest.java   | 22 +++++++++++++++++++
 4 files changed, 41 insertions(+), 3 deletions(-)

diff --git a/engine/src/flutter/shell/platform/android/io/flutter/app/FlutterPluginRegistry.java b/engine/src/flutter/shell/platform/android/io/flutter/app/FlutterPluginRegistry.java
index b1979694cff..2a7173634ec 100644
--- a/engine/src/flutter/shell/platform/android/io/flutter/app/FlutterPluginRegistry.java
+++ b/engine/src/flutter/shell/platform/android/io/flutter/app/FlutterPluginRegistry.java
@@ -86,7 +86,7 @@ public class FlutterPluginRegistry
 
   public void detach() {
     mPlatformViewsController.detach();
-    mPlatformViewsController.onFlutterViewDestroyed();
+    mPlatformViewsController.onDetachedFromJNI();
     mFlutterView = null;
     mActivity = null;
   }
@@ -239,6 +239,6 @@ public class FlutterPluginRegistry
   }
 
   public void destroy() {
-    mPlatformViewsController.onFlutterViewDestroyed();
+    mPlatformViewsController.onDetachedFromJNI();
   }
 }
diff --git a/engine/src/flutter/shell/platform/android/io/flutter/embedding/engine/FlutterEngine.java b/engine/src/flutter/shell/platform/android/io/flutter/embedding/engine/FlutterEngine.java
index dfd2bd674c5..271a1a8ec24 100644
--- a/engine/src/flutter/shell/platform/android/io/flutter/embedding/engine/FlutterEngine.java
+++ b/engine/src/flutter/shell/platform/android/io/flutter/embedding/engine/FlutterEngine.java
@@ -225,6 +225,7 @@ public class FlutterEngine {
     textInputChannel = new TextInputChannel(dartExecutor);
 
     this.platformViewsController = platformViewsController;
+    this.platformViewsController.onAttachedToJNI();
 
     this.pluginRegistry =
         new FlutterEnginePluginRegistry(context.getApplicationContext(), this, flutterLoader);
@@ -289,6 +290,7 @@ public class FlutterEngine {
     Log.v(TAG, "Destroying.");
     // The order that these things are destroyed is important.
     pluginRegistry.destroy();
+    platformViewsController.onDetachedFromJNI();
     dartExecutor.onDetachedFromJNI();
     flutterJNI.removeEngineLifecycleListener(engineLifecycleListener);
     flutterJNI.detachFromNativeAndReleaseResources();
diff --git a/engine/src/flutter/shell/platform/android/io/flutter/plugin/platform/PlatformViewsController.java b/engine/src/flutter/shell/platform/android/io/flutter/plugin/platform/PlatformViewsController.java
index 6c87e20c0fd..cc5dfc91af8 100644
--- a/engine/src/flutter/shell/platform/android/io/flutter/plugin/platform/PlatformViewsController.java
+++ b/engine/src/flutter/shell/platform/android/io/flutter/plugin/platform/PlatformViewsController.java
@@ -404,7 +404,21 @@ public class PlatformViewsController implements PlatformViewsAccessibilityDelega
     return registry;
   }
 
-  public void onFlutterViewDestroyed() {
+  /**
+   * Invoked when the {@link io.flutter.embedding.engine.FlutterEngine} that owns this {@link
+   * PlatformViewsController} attaches to JNI.
+   */
+  public void onAttachedToJNI() {
+    // Currently no action needs to be taken after JNI attachment.
+  }
+
+  /**
+   * Invoked when the {@link io.flutter.embedding.engine.FlutterEngine} that owns this {@link
+   * PlatformViewsController} detaches from JNI.
+   */
+  public void onDetachedFromJNI() {
+    // Dispose all virtual displays so that any future updates to textures will not be
+    // propagated to the native peer.
     flushAllViews();
   }
 
diff --git a/engine/src/flutter/shell/platform/android/test/io/flutter/embedding/engine/FlutterEngineTest.java b/engine/src/flutter/shell/platform/android/test/io/flutter/embedding/engine/FlutterEngineTest.java
index c95612281f1..9a15364373b 100644
--- a/engine/src/flutter/shell/platform/android/test/io/flutter/embedding/engine/FlutterEngineTest.java
+++ b/engine/src/flutter/shell/platform/android/test/io/flutter/embedding/engine/FlutterEngineTest.java
@@ -102,6 +102,28 @@ public class FlutterEngineTest {
     verify(platformViewsController, times(1)).onPreEngineRestart();
   }
 
+  @Test
+  public void itNotifiesPlatformViewsControllerAboutJNILifecycle() {
+    FlutterJNI mockFlutterJNI = mock(FlutterJNI.class);
+    when(mockFlutterJNI.isAttached()).thenReturn(true);
+
+    PlatformViewsController platformViewsController = mock(PlatformViewsController.class);
+
+    // Execute behavior under test.
+    FlutterEngine engine =
+        new FlutterEngine(
+            RuntimeEnvironment.application,
+            mock(FlutterLoader.class),
+            mockFlutterJNI,
+            platformViewsController,
+            /*dartVmArgs=*/ new String[] {},
+            /*automaticallyRegisterPlugins=*/ false);
+    verify(platformViewsController, times(1)).onAttachedToJNI();
+
+    engine.destroy();
+    verify(platformViewsController, times(1)).onDetachedFromJNI();
+  }
+
   @Test
   public void itUsesApplicationContext() {
     Context context = mock(Context.class);