Test dynamic surface switch (#61918)

dev/integration_tests/hybrid_android_views/android/app/src/main/java/io/flutter/integration/androidviews/MainActivity.java

@@ -12,9 +12,14 @@ import android.view.MotionEvent;
 import android.view.View;
 import android.view.ViewGroup;
 
+import java.lang.StringBuilder;
 import java.util.HashMap;
 
 import io.flutter.embedding.android.FlutterActivity;
+import io.flutter.embedding.android.FlutterImageView;
+import io.flutter.embedding.android.FlutterSurfaceView;
+import io.flutter.embedding.android.FlutterTextureView;
+import io.flutter.embedding.android.FlutterView;
 import io.flutter.embedding.engine.dart.DartExecutor;
 import io.flutter.embedding.engine.FlutterEngine;
 import io.flutter.plugin.common.MethodCall;
@@ -36,6 +41,63 @@ public class MainActivity extends FlutterActivity implements MethodChannel.Metho
         return ((ViewGroup)root.getChildAt(0)).getChildAt(0);
     }
 
+    private String getViewName(View view) {
+        if (view instanceof FlutterImageView) {
+            return "FlutterImageView";
+        }
+        if (view instanceof FlutterSurfaceView) {
+            return "FlutterSurfaceView";
+        }
+        if (view instanceof FlutterTextureView) {
+            return "FlutterTextureView";
+        }
+        if (view instanceof FlutterView) {
+            return "FlutterView";
+        }
+        if (view instanceof ViewGroup) {
+            return "ViewGroup";
+        }
+        return "View";
+    }
+
+    private void recurseViewHierarchy(View current, String padding, StringBuilder builder) {
+        if (current.getVisibility() != View.VISIBLE || current.getAlpha() == 0) {
+            return;
+        }
+        String name = getViewName(current);
+        builder.append(padding);
+        builder.append("|-");
+        builder.append(name);
+        builder.append("\n");
+
+        if (current instanceof ViewGroup) {
+            ViewGroup viewGroup = (ViewGroup) current;
+            for (int index = 0; index < viewGroup.getChildCount(); index++) {
+                recurseViewHierarchy(viewGroup.getChildAt(index), padding + "  ", builder);
+            }
+        }
+    }
+
+    /**
+     * Serializes the view hierarchy, so it can be sent to Dart over the method channel.
+     *
+     * Notation:
+     * |- <view-name>
+     *   |- ... child view ordered by z order.
+     *
+     * Example output:
+     * |- FlutterView
+     *   |- FlutterImageView
+     *      |- ViewGroup
+     *        |- View
+     */
+    private String getSerializedViewHierarchy() {
+        View root = getFlutterView();
+        StringBuilder builder = new StringBuilder();
+        recurseViewHierarchy(root, "", builder);
+        return builder.toString();
+    }
+
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
@@ -65,19 +127,23 @@ public class MainActivity extends FlutterActivity implements MethodChannel.Metho
                 getExternalStoragePermissions();
                 return;
             case "synthesizeEvent":
-                synthesizeEvent(methodCall, result);
+                synthesizeEvent(methodCall);
+                result.success(null);
+                return;
+             case "getViewHierarchy":
+                String viewHierarchy = getSerializedViewHierarchy();
+                result.success(viewHierarchy);
                 return;
         }
         result.notImplemented();
     }
 
     @SuppressWarnings("unchecked")
-    public void synthesizeEvent(MethodCall methodCall, MethodChannel.Result result) {
+    public void synthesizeEvent(MethodCall methodCall) {
         MotionEvent event = MotionEventCodec.decode((HashMap<String, Object>) methodCall.arguments());
         getFlutterView().dispatchTouchEvent(event);
         // TODO(egarciad): This can be cleaned up.
         mMethodChannel.invokeMethod("onTouch", MotionEventCodec.encode(event));
-        result.success(null);
     }
 
     @Override

dev/integration_tests/hybrid_android_views/lib/android_platform_view.dart

@@ -8,6 +8,8 @@ import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter/services.dart';
 
+MethodChannel channel = const MethodChannel('android_views_integration');
+
 class AndroidPlatformView extends StatelessWidget {
   /// Creates a platform view for Android, which is rendered as a
   /// native view.

dev/integration_tests/hybrid_android_views/lib/future_data_handler.dart

@@ -0,0 +1,35 @@
+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:async';
+
+import 'package:flutter_driver/driver_extension.dart';
+
+typedef DriverHandler = Future<String> Function();
+
+/// Wraps a flutter driver [DataHandler] with one that waits until a delegate is set.
+///
+/// This allows the driver test to call [FlutterDriver.requestData] before the handler was
+/// set by the app in which case the requestData call will only complete once the app is ready
+/// for it.
+class FutureDataHandler {
+  final Map<String, Completer<DriverHandler>> _handlers = <String, Completer<DriverHandler>>{};
+
+  /// Registers a lazy handler that will be invoked on the next message from the driver.
+  Completer<DriverHandler> registerHandler(String key) {
+    _handlers[key] = Completer<DriverHandler>();
+    return _handlers[key];
+  }
+
+  Future<String> handleMessage(String message) async {
+    if (_handlers[message] == null) {
+      return 'Unsupported driver message: $message.\n'
+             'Supported messages are: ${_handlers.keys}.';
+    }
+    final DriverHandler handler = await _handlers[message].future;
+    return handler();
+  }
+}
+
+FutureDataHandler driverDataHandler = FutureDataHandler();

dev/integration_tests/hybrid_android_views/lib/main.dart

@@ -5,6 +5,7 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_driver/driver_extension.dart';
 
+import 'future_data_handler.dart';
 import 'motion_events_page.dart';
 import 'nested_view_event_page.dart';
 import 'page.dart';

dev/integration_tests/hybrid_android_views/lib/motion_events_page.dart

@@ -8,15 +8,13 @@ import 'dart:typed_data';
 
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
-import 'package:flutter_driver/driver_extension.dart';
 import 'package:path_provider/path_provider.dart';
 
 import 'android_platform_view.dart';
+import 'future_data_handler.dart';
 import 'motion_event_diff.dart';
 import 'page.dart';
 
-MethodChannel channel = const MethodChannel('android_views_integration');
-
 const String kEventsFileName = 'touchEvents';
 
 class MotionEventsPage extends PageWidget {
@@ -29,22 +27,6 @@ class MotionEventsPage extends PageWidget {
   }
 }
 
-/// Wraps a flutter driver [DataHandler] with one that waits until a delegate is set.
-///
-/// This allows the driver test to call [FlutterDriver.requestData] before the handler was
-/// set by the app in which case the requestData call will only complete once the app is ready
-/// for it.
-class FutureDataHandler {
-  final Completer<DataHandler> handlerCompleter = Completer<DataHandler>();
-
-  Future<String> handleMessage(String message) async {
-    final DataHandler handler = await handlerCompleter.future;
-    return handler(message);
-  }
-}
-
-FutureDataHandler driverDataHandler = FutureDataHandler();
-
 class MotionEventsBody extends StatefulWidget {
   @override
   State createState() => MotionEventsBodyState();
@@ -196,7 +178,7 @@ class MotionEventsBodyState extends State<MotionEventsBody> {
   void onPlatformViewCreated(int id) {
     viewChannel = MethodChannel('simple_view/$id');
     viewChannel.setMethodCallHandler(onViewMethodChannelCall);
-    driverDataHandler.handlerCompleter.complete(handleDriverMessage);
+    driverDataHandler.registerHandler('run test').complete(playEventsFile);
   }
 
   void listenToFlutterViewEvents() {
@@ -206,14 +188,6 @@ class MotionEventsBodyState extends State<MotionEventsBody> {
     });
   }
 
-  Future<String> handleDriverMessage(String message) async {
-    switch (message) {
-      case 'run test':
-        return playEventsFile();
-    }
-    return 'unknown message: "$message"';
-  }
-
   Future<dynamic> onMethodChannelCall(MethodCall call) {
     switch (call.method) {
       case 'onTouch':

dev/integration_tests/hybrid_android_views/lib/nested_view_event_page.dart

@@ -10,6 +10,7 @@ import 'package:flutter/services.dart';
 import 'package:flutter/widgets.dart';
 
 import 'android_platform_view.dart';
+import 'future_data_handler.dart';
 import 'page.dart';
 
 class NestedViewEventPage extends PageWidget {
@@ -38,6 +39,7 @@ class NestedViewEventBodyState extends State<NestedViewEventBody> {
   String lastError;
   int id;
   int nestedViewClickCount = 0;
+  bool showPlatformView = true;
 
   @override
   Widget build(BuildContext context) {
@@ -49,10 +51,12 @@ class NestedViewEventBodyState extends State<NestedViewEventBody> {
         children: <Widget>[
           SizedBox(
             height: 300,
-            child: AndroidPlatformView(
+              child: showPlatformView ?
-              viewType: 'simple_view',
+                AndroidPlatformView(
-              onPlatformViewCreated: onPlatformViewCreated,
+                  key: const ValueKey<String>('PlatformView'),
-            ),
+                  viewType: 'simple_view',
+                  onPlatformViewCreated: onPlatformViewCreated,
+                ) : null,
           ),
           if (lastTestStatus != _LastTestStatus.pending) _statusWidget(),
           if (viewChannel != null) ... <Widget>[
@@ -61,6 +65,11 @@ class NestedViewEventBodyState extends State<NestedViewEventBody> {
               child: const Text('SHOW ALERT DIALOG'),
               onPressed: onShowAlertDialogPressed,
             ),
+            RaisedButton(
+              key: const ValueKey<String>('TogglePlatformView'),
+              child: const Text('TOGGLE PLATFORM VIEW'),
+              onPressed: onTogglePlatformView,
+            ),
             Row(
               children: <Widget>[
                 RaisedButton(
@@ -120,6 +129,12 @@ class NestedViewEventBodyState extends State<NestedViewEventBody> {
     }
   }
 
+  Future<void> onTogglePlatformView() async {
+    setState(() {
+      showPlatformView = !showPlatformView;
+    });
+  }
+
   Future<void> onChildViewPressed() async {
     try {
       await viewChannel.invokeMethod<void>('addChildViewAndWaitForClick');
@@ -152,5 +167,7 @@ class NestedViewEventBodyState extends State<NestedViewEventBody> {
     setState(() {
       viewChannel = MethodChannel('simple_view/$id');
     });
+    driverDataHandler.registerHandler('hierarchy')
+      .complete(() => channel.invokeMethod<String>('getViewHierarchy'));
   }
 }

dev/integration_tests/hybrid_android_views/test_driver/main_test.dart

@@ -18,10 +18,8 @@ Future<void> main() async {
   });
 
   // Each test below must return back to the home page after finishing.
-
   test('MotionEvent recomposition', () async {
-    final SerializableFinder motionEventsListTile =
+    final SerializableFinder motionEventsListTile = find.byValueKey('MotionEventsListTile');
-    find.byValueKey('MotionEventsListTile');
     await driver.tap(motionEventsListTile);
     await driver.waitFor(find.byValueKey('PlatformView'));
     final String errorMessage = await driver.requestData('run test');
@@ -30,8 +28,7 @@ Future<void> main() async {
     await driver.tap(backButton);
   });
 
-  group('Nested View Event', ()
+  group('Nested View Event', () {
-  {
     setUpAll(() async {
       final SerializableFinder wmListTile =
       find.byValueKey('NestedViewEventTile');
@@ -44,8 +41,7 @@ Future<void> main() async {
     });
 
     test('AlertDialog from platform view context', () async {
-      final SerializableFinder showAlertDialog = find.byValueKey(
+      final SerializableFinder showAlertDialog = find.byValueKey('ShowAlertDialog');
-          'ShowAlertDialog');
       await driver.waitFor(showAlertDialog);
       await driver.tap(showAlertDialog);
       final String status = await driver.getText(find.byValueKey('Status'));
@@ -58,8 +54,60 @@ Future<void> main() async {
       await driver.tap(addChildView);
       final SerializableFinder tapChildView = find.byValueKey('TapChildView');
       await driver.tap(tapChildView);
-      final String nestedViewClickCount = await driver.getText(find.byValueKey('NestedViewClickCount'));
+      final String nestedViewClickCount =
+        await driver.getText(find.byValueKey('NestedViewClickCount'));
       expect(nestedViewClickCount, 'Click count: 1');
     });
   });
+
+  group('Flutter surface switch', () {
+    setUpAll(() async {
+      final SerializableFinder wmListTile = find.byValueKey('NestedViewEventTile');
+      await driver.tap(wmListTile);
+    });
+
+    tearDownAll(() async {
+      await driver.waitFor(find.pageBack());
+      await driver.tap(find.pageBack());
+    });
+
+    test('Uses FlutterImageView when Android view is on the screen', () async {
+      await driver.waitFor(find.byValueKey('PlatformView'));
+
+      expect(
+        await driver.requestData('hierarchy'),
+        '|-FlutterView\n'
+        '  |-FlutterSurfaceView\n'  // Flutter UI (hidden)
+        '  |-FlutterImageView\n' // Flutter UI (background surface)
+        '  |-ViewGroup\n'  // Platform View
+        '    |-ViewGroup\n'
+        '  |-FlutterImageView\n'  // Flutter UI (overlay surface)
+      );
+
+      // Hide platform view.
+      final SerializableFinder togglePlatformView = find.byValueKey('TogglePlatformView');
+      await driver.tap(togglePlatformView);
+      await driver.waitForAbsent(find.byValueKey('PlatformView'));
+
+      expect(
+        await driver.requestData('hierarchy'),
+        '|-FlutterView\n'
+        '  |-FlutterSurfaceView\n' // Just the Flutter UI
+      );
+
+      // Show platform view again.
+      await driver.tap(togglePlatformView);
+      await driver.waitFor(find.byValueKey('PlatformView'));
+
+      expect(
+        await driver.requestData('hierarchy'),
+        '|-FlutterView\n'
+        '  |-FlutterSurfaceView\n' // Flutter UI (hidden)
+        '  |-FlutterImageView\n' // Flutter UI (background surface)
+        '  |-ViewGroup\n' // Platform View
+        '    |-ViewGroup\n'
+        '  |-FlutterImageView\n' // Flutter UI (overlay surface)
+      );
+    });
+  });
 }