System mouse cursor: Android (#18569)

Adds system mouse cursor to the Android engine.

ci/licenses_golden/licenses_flutter

@@ -727,6 +727,7 @@ FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/engine/system
 FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/engine/systemchannels/KeyEventChannel.java
 FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/engine/systemchannels/LifecycleChannel.java
 FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/engine/systemchannels/LocalizationChannel.java
+FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/engine/systemchannels/MouseCursorChannel.java
 FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/engine/systemchannels/NavigationChannel.java
 FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/engine/systemchannels/PlatformChannel.java
 FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/engine/systemchannels/PlatformViewsChannel.java
@@ -754,6 +755,7 @@ FILE: ../../../flutter/shell/platform/android/io/flutter/plugin/common/StringCod
 FILE: ../../../flutter/shell/platform/android/io/flutter/plugin/editing/FlutterTextUtils.java
 FILE: ../../../flutter/shell/platform/android/io/flutter/plugin/editing/InputConnectionAdaptor.java
 FILE: ../../../flutter/shell/platform/android/io/flutter/plugin/editing/TextInputPlugin.java
+FILE: ../../../flutter/shell/platform/android/io/flutter/plugin/mouse/MouseCursorPlugin.java
 FILE: ../../../flutter/shell/platform/android/io/flutter/plugin/platform/AccessibilityEventsDelegate.java
 FILE: ../../../flutter/shell/platform/android/io/flutter/plugin/platform/PlatformPlugin.java
 FILE: ../../../flutter/shell/platform/android/io/flutter/plugin/platform/PlatformView.java

shell/platform/android/BUILD.gn

@@ -177,6 +177,7 @@ android_java_sources = [
   "io/flutter/embedding/engine/systemchannels/KeyEventChannel.java",
   "io/flutter/embedding/engine/systemchannels/LifecycleChannel.java",
   "io/flutter/embedding/engine/systemchannels/LocalizationChannel.java",
+  "io/flutter/embedding/engine/systemchannels/MouseCursorChannel.java",
   "io/flutter/embedding/engine/systemchannels/NavigationChannel.java",
   "io/flutter/embedding/engine/systemchannels/PlatformChannel.java",
   "io/flutter/embedding/engine/systemchannels/PlatformViewsChannel.java",
@@ -204,6 +205,7 @@ android_java_sources = [
   "io/flutter/plugin/editing/FlutterTextUtils.java",
   "io/flutter/plugin/editing/InputConnectionAdaptor.java",
   "io/flutter/plugin/editing/TextInputPlugin.java",
+  "io/flutter/plugin/mouse/MouseCursorPlugin.java",
   "io/flutter/plugin/platform/AccessibilityEventsDelegate.java",
   "io/flutter/plugin/platform/PlatformPlugin.java",
   "io/flutter/plugin/platform/PlatformView.java",
@@ -442,6 +444,7 @@ action("robolectric_tests") {
     "test/io/flutter/plugin/common/StandardMethodCodecTest.java",
     "test/io/flutter/plugin/editing/InputConnectionAdaptorTest.java",
     "test/io/flutter/plugin/editing/TextInputPluginTest.java",
+    "test/io/flutter/plugin/mouse/MouseCursorPluginTest.java",
     "test/io/flutter/plugin/platform/PlatformPluginTest.java",
     "test/io/flutter/plugin/platform/SingleViewPresentationTest.java",
     "test/io/flutter/plugins/GeneratedPluginRegistrant.java",

shell/platform/android/io/flutter/embedding/android/FlutterView.java

@@ -17,6 +17,7 @@ import android.util.AttributeSet;
 import android.util.SparseArray;
 import android.view.KeyEvent;
 import android.view.MotionEvent;
+import android.view.PointerIcon;
 import android.view.Surface;
 import android.view.View;
 import android.view.ViewStructure;
@@ -39,6 +40,7 @@ import io.flutter.embedding.engine.renderer.FlutterUiDisplayListener;
 import io.flutter.embedding.engine.renderer.RenderSurface;
 import io.flutter.embedding.engine.systemchannels.SettingsChannel;
 import io.flutter.plugin.editing.TextInputPlugin;
+import io.flutter.plugin.mouse.MouseCursorPlugin;
 import io.flutter.plugin.platform.PlatformViewsController;
 import io.flutter.view.AccessibilityBridge;
 import java.util.ArrayList;
@@ -75,7 +77,7 @@ import java.util.Set;
  * See <a>https://source.android.com/devices/graphics/arch-tv#surface_or_texture</a> for more
  * information comparing {@link android.view.SurfaceView} and {@link android.view.TextureView}.
  */
-public class FlutterView extends FrameLayout {
+public class FlutterView extends FrameLayout implements MouseCursorPlugin.MouseCursorViewDelegate {
   private static final String TAG = "FlutterView";
 
   // Internal view hierarchy references.
@@ -97,6 +99,7 @@ public class FlutterView extends FrameLayout {
   //
   // These components essentially add some additional behavioral logic on top of
   // existing, stateless system channels, e.g., KeyEventChannel, TextInputChannel, etc.
+  @Nullable private MouseCursorPlugin mouseCursorPlugin;
   @Nullable private TextInputPlugin textInputPlugin;
   @Nullable private AndroidKeyProcessor androidKeyProcessor;
   @Nullable private AndroidTouchProcessor androidTouchProcessor;
@@ -756,6 +759,16 @@ public class FlutterView extends FrameLayout {
   }
   // -------- End: Accessibility ---------
 
+  // -------- Start: Mouse -------
+  @Override
+  @TargetApi(Build.VERSION_CODES.N)
+  @RequiresApi(Build.VERSION_CODES.N)
+  @NonNull
+  public PointerIcon getSystemPointerIcon(int type) {
+    return PointerIcon.getSystemIcon(getContext(), type);
+  }
+  // -------- End: Mouse ---------
+
   /**
    * Connects this {@code FlutterView} to the given {@link FlutterEngine}.
    *
@@ -794,6 +807,9 @@ public class FlutterView extends FrameLayout {
 
     // Initialize various components that know how to process Android View I/O
     // in a way that Flutter understands.
+    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
+      mouseCursorPlugin = new MouseCursorPlugin(this, this.flutterEngine.getMouseCursorChannel());
+    }
     textInputPlugin =
         new TextInputPlugin(
             this,

shell/platform/android/io/flutter/embedding/engine/FlutterEngine.java

@@ -21,6 +21,7 @@ import io.flutter.embedding.engine.systemchannels.AccessibilityChannel;
 import io.flutter.embedding.engine.systemchannels.KeyEventChannel;
 import io.flutter.embedding.engine.systemchannels.LifecycleChannel;
 import io.flutter.embedding.engine.systemchannels.LocalizationChannel;
+import io.flutter.embedding.engine.systemchannels.MouseCursorChannel;
 import io.flutter.embedding.engine.systemchannels.NavigationChannel;
 import io.flutter.embedding.engine.systemchannels.PlatformChannel;
 import io.flutter.embedding.engine.systemchannels.SettingsChannel;
@@ -77,6 +78,7 @@ public class FlutterEngine {
   @NonNull private final KeyEventChannel keyEventChannel;
   @NonNull private final LifecycleChannel lifecycleChannel;
   @NonNull private final LocalizationChannel localizationChannel;
+  @NonNull private final MouseCursorChannel mouseCursorChannel;
   @NonNull private final NavigationChannel navigationChannel;
   @NonNull private final PlatformChannel platformChannel;
   @NonNull private final SettingsChannel settingsChannel;
@@ -218,6 +220,7 @@ public class FlutterEngine {
     keyEventChannel = new KeyEventChannel(dartExecutor);
     lifecycleChannel = new LifecycleChannel(dartExecutor);
     localizationChannel = new LocalizationChannel(dartExecutor);
+    mouseCursorChannel = new MouseCursorChannel(dartExecutor);
     navigationChannel = new NavigationChannel(dartExecutor);
     platformChannel = new PlatformChannel(dartExecutor);
     settingsChannel = new SettingsChannel(dartExecutor);
@@ -391,6 +394,12 @@ public class FlutterEngine {
     return systemChannel;
   }
 
+  /** System channel that sends and receives text input requests and state. */
+  @NonNull
+  public MouseCursorChannel getMouseCursorChannel() {
+    return mouseCursorChannel;
+  }
+
   /** System channel that sends and receives text input requests and state. */
   @NonNull
   public TextInputChannel getTextInputChannel() {

shell/platform/android/io/flutter/embedding/engine/systemchannels/MouseCursorChannel.java

+// Copyright 2013 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.
+
+package io.flutter.embedding.engine.systemchannels;
+
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+import androidx.annotation.VisibleForTesting;
+import io.flutter.Log;
+import io.flutter.embedding.engine.dart.DartExecutor;
+import io.flutter.plugin.common.MethodCall;
+import io.flutter.plugin.common.MethodChannel;
+import io.flutter.plugin.common.StandardMethodCodec;
+import java.util.HashMap;
+
+/** System channel that receives requests for mouse cursor behavior, e.g., set as system cursors. */
+public class MouseCursorChannel {
+  private static final String TAG = "MouseCursorChannel";
+
+  @NonNull public final MethodChannel channel;
+  @Nullable private MouseCursorMethodHandler mouseCursorMethodHandler;
+
+  public MouseCursorChannel(@NonNull DartExecutor dartExecutor) {
+    channel = new MethodChannel(dartExecutor, "flutter/mousecursor", StandardMethodCodec.INSTANCE);
+    channel.setMethodCallHandler(parsingMethodCallHandler);
+  }
+
+  /**
+   * Sets the {@link MouseCursorMethodHandler} which receives all events and requests that are
+   * parsed from the underlying platform channel.
+   */
+  public void setMethodHandler(@Nullable MouseCursorMethodHandler mouseCursorMethodHandler) {
+    this.mouseCursorMethodHandler = mouseCursorMethodHandler;
+  }
+
+  @NonNull
+  private final MethodChannel.MethodCallHandler parsingMethodCallHandler =
+      new MethodChannel.MethodCallHandler() {
+        @Override
+        public void onMethodCall(@NonNull MethodCall call, @NonNull MethodChannel.Result result) {
+          if (mouseCursorMethodHandler == null) {
+            // If no explicit mouseCursorMethodHandler has been registered then we don't
+            // need to forward this call to an API. Return.
+            return;
+          }
+
+          final String method = call.method;
+          Log.v(TAG, "Received '" + method + "' message.");
+          try {
+            // More methods are expected to be added here, hence the switch.
+            switch (method) {
+              case "activateSystemCursor":
+                @SuppressWarnings("unchecked")
+                final HashMap<String, Object> data = (HashMap<String, Object>) call.arguments;
+                final String kind = (String) data.get("kind");
+                try {
+                  mouseCursorMethodHandler.activateSystemCursor(kind);
+                } catch (Exception e) {
+                  result.error("error", "Error when setting cursors: " + e.getMessage(), null);
+                  break;
+                }
+                result.success(true);
+                break;
+              default:
+            }
+          } catch (Exception e) {
+            result.error("error", "Unhandled error: " + e.getMessage(), null);
+          }
+        }
+      };
+
+  @VisibleForTesting
+  public void synthesizeMethodCall(@NonNull MethodCall call, @NonNull MethodChannel.Result result) {
+    parsingMethodCallHandler.onMethodCall(call, result);
+  }
+
+  public interface MouseCursorMethodHandler {
+    // Called when the pointer should start displaying a system mouse cursor
+    // specified by {@code shapeCode}.
+    public void activateSystemCursor(@NonNull String kind);
+  }
+}

shell/platform/android/io/flutter/plugin/mouse/MouseCursorPlugin.java

+// Copyright 2013 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.
+
+package io.flutter.plugin.mouse;
+
+import android.annotation.TargetApi;
+import android.os.Build;
+import android.view.PointerIcon;
+import androidx.annotation.NonNull;
+import androidx.annotation.RequiresApi;
+import io.flutter.embedding.engine.systemchannels.MouseCursorChannel;
+import java.util.HashMap;
+
+/** A mandatory plugin that handles mouse cursor requests. */
+@TargetApi(Build.VERSION_CODES.N)
+@RequiresApi(Build.VERSION_CODES.N)
+public class MouseCursorPlugin {
+  @NonNull private final MouseCursorViewDelegate mView;
+  @NonNull private final MouseCursorChannel mouseCursorChannel;
+
+  public MouseCursorPlugin(
+      @NonNull MouseCursorViewDelegate view, @NonNull MouseCursorChannel mouseCursorChannel) {
+    mView = view;
+
+    this.mouseCursorChannel = mouseCursorChannel;
+    mouseCursorChannel.setMethodHandler(
+        new MouseCursorChannel.MouseCursorMethodHandler() {
+          @Override
+          public void activateSystemCursor(@NonNull String kind) {
+            mView.setPointerIcon(resolveSystemCursor(kind));
+          }
+        });
+  }
+
+  /**
+   * Return a pointer icon object for a system cursor.
+   *
+   * <p>This method guarantees to return a non-null object.
+   */
+  private PointerIcon resolveSystemCursor(@NonNull String kind) {
+    if (MouseCursorPlugin.systemCursorConstants == null) {
+      // Initialize the map when first used, because the map can grow big in the future (~70)
+      // and most mobile devices will not use them.
+      MouseCursorPlugin.systemCursorConstants =
+          new HashMap<String, Integer>() {
+            private static final long serialVersionUID = 1L;
+
+            {
+              put("none", Integer.valueOf(PointerIcon.TYPE_NULL));
+              //  "basic": default
+              put("click", Integer.valueOf(PointerIcon.TYPE_HAND));
+              put("text", Integer.valueOf(PointerIcon.TYPE_TEXT));
+              //  "forbidden": default
+              put("grab", Integer.valueOf(PointerIcon.TYPE_GRAB));
+              put("grabbing", Integer.valueOf(PointerIcon.TYPE_GRABBING));
+            }
+          };
+    }
+
+    final int cursorConstant =
+        MouseCursorPlugin.systemCursorConstants.getOrDefault(kind, PointerIcon.TYPE_ARROW);
+    return mView.getSystemPointerIcon(cursorConstant);
+  }
+
+  /**
+   * Detaches the text input plugin from the platform views controller.
+   *
+   * <p>The MouseCursorPlugin instance should not be used after calling this.
+   */
+  public void destroy() {
+    mouseCursorChannel.setMethodHandler(null);
+  }
+
+  /**
+   * A map from Flutter's system cursor {@code kind} to Android's pointer icon constants.
+   *
+   * <p>It is null until the first time a system cursor is requested, at which time it is filled
+   * with the entire mapping.
+   */
+  @NonNull private static HashMap<String, Integer> systemCursorConstants;
+
+  /**
+   * Delegate interface for requesting the system to display a pointer icon object.
+   *
+   * <p>Typically implemented by an {@link android.view.View}, such as a {@code FlutterView}.
+   */
+  public interface MouseCursorViewDelegate {
+    /**
+     * Gets a system pointer icon object for the given {@code type}.
+     *
+     * <p>If typeis not recognized, returns the default pointer icon.
+     *
+     * <p>This is typically implemented by calling {@link android.view.PointerIcon.getSystemIcon}
+     * with the context associated with this view.
+     */
+    public PointerIcon getSystemPointerIcon(int type);
+
+    /**
+     * Request the pointer to display the specified icon object.
+     *
+     * <p>If the delegate is implemented by a {@link android.view.View}, then this method is
+     * automatically implemented by View.
+     */
+    public void setPointerIcon(@NonNull PointerIcon icon);
+  }
+}

shell/platform/android/io/flutter/view/FlutterView.java

@@ -24,6 +24,7 @@ import android.util.Log;
 import android.util.SparseArray;
 import android.view.KeyEvent;
 import android.view.MotionEvent;
+import android.view.PointerIcon;
 import android.view.Surface;
 import android.view.SurfaceHolder;
 import android.view.SurfaceView;
@@ -49,6 +50,7 @@ import io.flutter.embedding.engine.systemchannels.AccessibilityChannel;
 import io.flutter.embedding.engine.systemchannels.KeyEventChannel;
 import io.flutter.embedding.engine.systemchannels.LifecycleChannel;
 import io.flutter.embedding.engine.systemchannels.LocalizationChannel;
+import io.flutter.embedding.engine.systemchannels.MouseCursorChannel;
 import io.flutter.embedding.engine.systemchannels.NavigationChannel;
 import io.flutter.embedding.engine.systemchannels.PlatformChannel;
 import io.flutter.embedding.engine.systemchannels.SettingsChannel;
@@ -57,6 +59,7 @@ import io.flutter.embedding.engine.systemchannels.TextInputChannel;
 import io.flutter.plugin.common.ActivityLifecycleListener;
 import io.flutter.plugin.common.BinaryMessenger;
 import io.flutter.plugin.editing.TextInputPlugin;
+import io.flutter.plugin.mouse.MouseCursorPlugin;
 import io.flutter.plugin.platform.PlatformPlugin;
 import io.flutter.plugin.platform.PlatformViewsController;
 import java.nio.ByteBuffer;
@@ -72,7 +75,8 @@ import java.util.concurrent.atomic.AtomicLong;
  * <p>Deprecation: {@link io.flutter.embedding.android.FlutterView} is the new API that now replaces
  * this class. See https://flutter.dev/go/android-project-migration for more migration details.
  */
-public class FlutterView extends SurfaceView implements BinaryMessenger, TextureRegistry {
+public class FlutterView extends SurfaceView
+    implements BinaryMessenger, TextureRegistry, MouseCursorPlugin.MouseCursorViewDelegate {
   /**
    * Interface for those objects that maintain and expose a reference to a {@code FlutterView} (such
    * as a full-screen Flutter activity).
@@ -120,6 +124,7 @@ public class FlutterView extends SurfaceView implements BinaryMessenger, Texture
   private final SystemChannel systemChannel;
   private final InputMethodManager mImm;
   private final TextInputPlugin mTextInputPlugin;
+  private final MouseCursorPlugin mMouseCursorPlugin;
   private final AndroidKeyProcessor androidKeyProcessor;
   private final AndroidTouchProcessor androidTouchProcessor;
   private AccessibilityBridge mAccessibilityNodeProvider;
@@ -221,6 +226,11 @@ public class FlutterView extends SurfaceView implements BinaryMessenger, Texture
         mNativeView.getPluginRegistry().getPlatformViewsController();
     mTextInputPlugin =
         new TextInputPlugin(this, new TextInputChannel(dartExecutor), platformViewsController);
+    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
+      mMouseCursorPlugin = new MouseCursorPlugin(this, new MouseCursorChannel(dartExecutor));
+    } else {
+      mMouseCursorPlugin = null;
+    }
     androidKeyProcessor = new AndroidKeyProcessor(keyEventChannel, mTextInputPlugin);
     androidTouchProcessor = new AndroidTouchProcessor(flutterRenderer);
     mNativeView
@@ -793,6 +803,14 @@ public class FlutterView extends SurfaceView implements BinaryMessenger, Texture
     }
   }
 
+  @Override
+  @TargetApi(Build.VERSION_CODES.N)
+  @RequiresApi(Build.VERSION_CODES.N)
+  @NonNull
+  public PointerIcon getSystemPointerIcon(int type) {
+    return PointerIcon.getSystemIcon(getContext(), type);
+  }
+
   @Override
   @UiThread
   public void send(String channel, ByteBuffer message) {

shell/platform/android/test/io/flutter/FlutterTestSuite.java

@@ -20,6 +20,7 @@ import io.flutter.plugin.common.StandardMessageCodecTest;
 import io.flutter.plugin.common.StandardMethodCodecTest;
 import io.flutter.plugin.editing.InputConnectionAdaptorTest;
 import io.flutter.plugin.editing.TextInputPluginTest;
+import io.flutter.plugin.mouse.MouseCursorPluginTest;
 import io.flutter.plugin.platform.PlatformPluginTest;
 import io.flutter.plugin.platform.SingleViewPresentationTest;
 import io.flutter.util.PreconditionsTest;
@@ -58,6 +59,7 @@ import test.io.flutter.embedding.engine.dart.DartExecutorTest;
   SingleViewPresentationTest.class,
   SmokeTest.class,
   TextInputPluginTest.class,
+  MouseCursorPluginTest.class,
   AccessibilityBridgeTest.class,
 })
 /** Runs all of the unit tests listed in the {@code @SuiteClasses} annotation. */

shell/platform/android/test/io/flutter/embedding/android/FlutterActivityAndFragmentDelegateTest.java

@@ -27,6 +27,7 @@ import io.flutter.embedding.engine.renderer.FlutterRenderer;
 import io.flutter.embedding.engine.systemchannels.AccessibilityChannel;
 import io.flutter.embedding.engine.systemchannels.LifecycleChannel;
 import io.flutter.embedding.engine.systemchannels.LocalizationChannel;
+import io.flutter.embedding.engine.systemchannels.MouseCursorChannel;
 import io.flutter.embedding.engine.systemchannels.NavigationChannel;
 import io.flutter.embedding.engine.systemchannels.SettingsChannel;
 import io.flutter.embedding.engine.systemchannels.SystemChannel;
@@ -615,6 +616,7 @@ public class FlutterActivityAndFragmentDelegateTest {
     when(engine.getNavigationChannel()).thenReturn(mock(NavigationChannel.class));
     when(engine.getSystemChannel()).thenReturn(mock(SystemChannel.class));
     when(engine.getTextInputChannel()).thenReturn(mock(TextInputChannel.class));
+    when(engine.getMouseCursorChannel()).thenReturn(mock(MouseCursorChannel.class));
     when(engine.getActivityControlSurface()).thenReturn(mock(ActivityControlSurface.class));
 
     return engine;

shell/platform/android/test/io/flutter/plugin/mouse/MouseCursorPluginTest.java

+package io.flutter.plugin.mouse;
+
+import static org.junit.Assert.assertEquals;
+import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+
+import android.annotation.TargetApi;
+import android.view.PointerIcon;
+import io.flutter.embedding.android.FlutterView;
+import io.flutter.embedding.engine.dart.DartExecutor;
+import io.flutter.embedding.engine.systemchannels.MouseCursorChannel;
+import io.flutter.plugin.common.MethodCall;
+import io.flutter.plugin.common.MethodChannel;
+import java.util.HashMap;
+import org.json.JSONException;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.RuntimeEnvironment;
+import org.robolectric.annotation.Config;
+
+@Config(
+    manifest = Config.NONE,
+    shadows = {})
+@RunWith(RobolectricTestRunner.class)
+@TargetApi(24)
+public class MouseCursorPluginTest {
+  @Test
+  public void mouseCursorPlugin_SetsSystemCursorOnRequest() throws JSONException {
+    // Initialize a general MouseCursorPlugin.
+    FlutterView testView = spy(new FlutterView(RuntimeEnvironment.application));
+    MouseCursorChannel mouseCursorChannel = new MouseCursorChannel(mock(DartExecutor.class));
+
+    MouseCursorPlugin mouseCursorPlugin = new MouseCursorPlugin(testView, mouseCursorChannel);
+
+    final StoredResult methodResult = new StoredResult();
+    mouseCursorChannel.synthesizeMethodCall(
+        new MethodCall(
+            "activateSystemCursor",
+            new HashMap<String, Object>() {
+              private static final long serialVersionUID = 1L;
+
+              {
+                put("device", 1);
+                put("kind", "text");
+              }
+            }),
+        methodResult);
+    verify(testView, times(1)).getSystemPointerIcon(PointerIcon.TYPE_TEXT);
+    verify(testView, times(1)).setPointerIcon(any(PointerIcon.class));
+    assertEquals(methodResult.result, Boolean.TRUE);
+  }
+}
+
+class StoredResult implements MethodChannel.Result {
+  Object result;
+
+  @Override
+  public void success(Object result) {
+    this.result = result;
+  }
+
+  @Override
+  public void error(String errorCode, String errorMessage, Object errorDetails) {}
+
+  @Override
+  public void notImplemented() {}
+}