Android Embedding Refactor PR31: Integrate platform views with the new embedding and the plugin shim.

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

@@ -16,6 +16,7 @@
 import android.os.Bundle;
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
+import android.support.v4.app.Fragment;
 import android.support.v4.app.FragmentActivity;
 import android.support.v4.app.FragmentManager;
 import android.util.TypedValue;
@@ -66,7 +67,10 @@
  * {@code Fragment}.
  */
 // TODO(mattcarroll): explain each call forwarded to Fragment (first requires resolution of PluginRegistry API).
-public class FlutterActivity extends FragmentActivity implements OnFirstFrameRenderedListener {
+public class FlutterActivity extends FragmentActivity
+    implements FlutterFragment.FlutterEngineProvider,
+    FlutterFragment.FlutterEngineConfigurator,
+    OnFirstFrameRenderedListener {
   private static final String TAG = "FlutterActivity";
 
   // Meta-data arguments, processed from manifest XML.
@@ -365,6 +369,27 @@ protected boolean shouldAttachEngineToActivity() {
     return true;
   }
 
+  /**
+   * Hook for subclasses to easily provide a custom {@code FlutterEngine}.
+   */
+  @Nullable
+  @Override
+  public FlutterEngine provideFlutterEngine(@NonNull Context context) {
+    // No-op. Hook for subclasses.
+    return null;
+  }
+
+  /**
+   * Hook for subclasses to easily configure a {@code FlutterEngine}, e.g., register
+   * plugins.
+   * <p>
+   * This method is called after {@link #provideFlutterEngine(Context)}.
+   */
+  @Override
+  public void configureFlutterEngine(@NonNull FlutterEngine flutterEngine) {
+    // No-op. Hook for subclasses.
+  }
+
   @Override
   public void onPostResume() {
     super.onPostResume();

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

@@ -6,6 +6,8 @@
 
 import static android.content.ComponentCallbacks2.TRIM_MEMORY_RUNNING_LOW;
 
+import android.app.Activity;
+import android.arch.lifecycle.Lifecycle;
 import android.content.Context;
 import android.content.Intent;
 import android.os.Build;
@@ -359,8 +361,13 @@ public void onAttach(@NonNull Context context) {
       // sync with the Activity. We use the Fragment's Lifecycle because it is possible that the
       // attached Activity is not a LifecycleOwner.
       Log.d(TAG, "Attaching FlutterEngine to the Activity that owns this Fragment.");
-      flutterEngine.getActivityControlSurface().attachToActivity(getActivity(), getLifecycle());
+      flutterEngine.getActivityControlSurface().attachToActivity(
+          getActivity(),
+          getLifecycle()
+      );
     }
+
+    configureFlutterEngine(flutterEngine);
   }
 
   private void initializeFlutter(@NonNull Context context) {
@@ -401,11 +408,11 @@ private void setupFlutterEngine() {
       // Defer to the Activity that owns us to provide a FlutterEngine.
       Log.d(TAG, "Deferring to attached Activity to provide a FlutterEngine.");
       FlutterEngineProvider flutterEngineProvider = (FlutterEngineProvider) attachedActivity;
-      flutterEngine = flutterEngineProvider.getFlutterEngine(getContext());
+      flutterEngine = flutterEngineProvider.provideFlutterEngine(getContext());
       if (flutterEngine != null) {
         isFlutterEngineFromActivity = true;
+        return;
       }
-      return;
     }
 
     // Neither our subclass, nor our owning Activity wanted to provide a custom FlutterEngine.
@@ -434,11 +441,34 @@ protected FlutterEngine createFlutterEngine(@NonNull Context context) {
     return null;
   }
 
+  /**
+   * Configures a {@link FlutterEngine} after its creation.
+   * <p>
+   * This method is called after the given {@link FlutterEngine} has been attached to the
+   * owning {@code FragmentActivity}. See
+   * {@link io.flutter.embedding.engine.plugins.activity.ActivityControlSurface#attachToActivity(Activity, Lifecycle)}.
+   * <p>
+   * It is possible that the owning {@code FragmentActivity} opted not to connect itself as
+   * an {@link io.flutter.embedding.engine.plugins.activity.ActivityControlSurface}. In that
+   * case, any configuration, e.g., plugins, must not expect or depend upon an available
+   * {@code Activity} at the time that this method is invoked.
+   * <p>
+   * The default behavior of this method is to defer to the owning {@code FragmentActivity}
+   * as a {@link FlutterEngineConfigurator}. Subclasses can override this method if the
+   * subclass needs to override the {@code FragmentActivity}'s behavior, or add to it.
+   */
+  protected void configureFlutterEngine(@NonNull FlutterEngine flutterEngine) {
+    FragmentActivity attachedActivity = getActivity();
+    if (attachedActivity instanceof FlutterEngineConfigurator) {
+      ((FlutterEngineConfigurator) attachedActivity).configureFlutterEngine(flutterEngine);
+    }
+  }
+
   @Nullable
   @Override
-  public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
+  public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
     Log.v(TAG, "Creating FlutterView.");
-    flutterView = new FlutterView(getContext(), getRenderMode(), getTransparencyMode());
+    flutterView = new FlutterView(getActivity(), getRenderMode(), getTransparencyMode());
     flutterView.addOnFirstFrameRenderedListener(onFirstFrameRenderedListener);
     return flutterView;
   }
@@ -548,10 +578,6 @@ public void run() {
         Log.v(TAG, "Attaching FlutterEngine to FlutterView.");
         flutterView.attachToFlutterEngine(flutterEngine);
 
-        // TODO(mattcarroll): the following call should exist here, but the plugin system needs to be revamped.
-        //                    The existing attach() method does not know how to handle this kind of FlutterView.
-        //flutterEngine.getPlugins().attach(this, getActivity());
-
         doInitialFlutterViewRun();
       }
     });
@@ -788,7 +814,7 @@ protected void onFirstFrameRendered() {}
    * {@link FlutterActivity}s and/or {@code FlutterFragments}.
    * <p>
    * If the {@link FragmentActivity} that owns this {@code FlutterFragment} implements
-   * {@code FlutterEngineProvider}, that {@link FlutterActivity} will be given an opportunity
+   * {@code FlutterEngineProvider}, that {@link FragmentActivity} will be given an opportunity
    * to provide a {@link FlutterEngine} instead of the {@code FlutterFragment} creating a
    * new one. The {@link FragmentActivity} can provide an existing, pre-warmed {@link FlutterEngine},
    * if desired.
@@ -804,6 +830,27 @@ public interface FlutterEngineProvider {
      * to provide its own {@code FlutterEngine} instance.
      */
     @Nullable
-    FlutterEngine getFlutterEngine(@NonNull Context context);
+    FlutterEngine provideFlutterEngine(@NonNull Context context);
+  }
+
+  /**
+   * Configures a {@link FlutterEngine} after it is created, e.g., adds plugins.
+   * <p>
+   * This interface may be applied to a {@link FragmentActivity} that owns a {@code FlutterFragment}.
+   */
+  public interface FlutterEngineConfigurator {
+    /**
+     * Configures the given {@link FlutterEngine}.
+     * <p>
+     * This method is called after the given {@link FlutterEngine} has been attached to the
+     * owning {@code FragmentActivity}. See
+     * {@link io.flutter.embedding.engine.plugins.activity.ActivityControlSurface#attachToActivity(Activity, Lifecycle)}.
+     * <p>
+     * It is possible that the owning {@code FragmentActivity} opted not to connect itself as
+     * an {@link io.flutter.embedding.engine.plugins.activity.ActivityControlSurface}. In that
+     * case, any configuration, e.g., plugins, must not expect or depend upon an available
+     * {@code Activity} at the time that this method is invoked.
+     */
+    void configureFlutterEngine(@NonNull FlutterEngine flutterEngine);
   }
 }

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

@@ -18,6 +18,7 @@
 import android.util.AttributeSet;
 import android.view.KeyEvent;
 import android.view.MotionEvent;
+import android.view.View;
 import android.view.WindowInsets;
 import android.view.accessibility.AccessibilityManager;
 import android.view.accessibility.AccessibilityNodeProvider;
@@ -36,6 +37,7 @@
 import io.flutter.embedding.engine.renderer.FlutterRenderer;
 import io.flutter.embedding.engine.renderer.OnFirstFrameRenderedListener;
 import io.flutter.plugin.editing.TextInputPlugin;
+import io.flutter.plugin.platform.PlatformViewsController;
 import io.flutter.view.AccessibilityBridge;
 
 /**
@@ -117,6 +119,8 @@ public void onFirstFrameRendered() {
    *   <li>{@link #renderMode} defaults to {@link RenderMode#surface}.</li>
    *   <li>{@link #transparencyMode} defaults to {@link TransparencyMode#opaque}.</li>
    * </ul>
+   * {@code FlutterView} requires an {@code Activity} instead of a generic {@code Context}
+   * to be compatible with {@link PlatformViewsController}.
    */
   public FlutterView(@NonNull Context context) {
     this(context, null, null, null);
@@ -127,6 +131,9 @@ public FlutterView(@NonNull Context context) {
    * and allows selection of a {@link #renderMode}.
    * <p>
    * {@link #transparencyMode} defaults to {@link TransparencyMode#opaque}.
+   * <p>
+   * {@code FlutterView} requires an {@code Activity} instead of a generic {@code Context}
+   * to be compatible with {@link PlatformViewsController}.
    */
   public FlutterView(@NonNull Context context, @NonNull RenderMode renderMode) {
     this(context, null, renderMode, null);
@@ -135,6 +142,9 @@ public FlutterView(@NonNull Context context, @NonNull RenderMode renderMode) {
   /**
    * Constructs a {@code FlutterView} programmatically, without any XML attributes,
    * assumes the use of {@link RenderMode#surface}, and allows selection of a {@link #transparencyMode}.
+   * <p>
+   * {@code FlutterView} requires an {@code Activity} instead of a generic {@code Context}
+   * to be compatible with {@link PlatformViewsController}.
    */
   public FlutterView(@NonNull Context context, @NonNull TransparencyMode transparencyMode) {
     this(context, null, RenderMode.surface, transparencyMode);
@@ -143,16 +153,21 @@ public FlutterView(@NonNull Context context, @NonNull TransparencyMode transpare
   /**
    * Constructs a {@code FlutterView} programmatically, without any XML attributes, and allows
    * a selection of {@link #renderMode} and {@link #transparencyMode}.
+   * <p>
+   * {@code FlutterView} requires an {@code Activity} instead of a generic {@code Context}
+   * to be compatible with {@link PlatformViewsController}.
    */
   public FlutterView(@NonNull Context context, @NonNull RenderMode renderMode, @NonNull TransparencyMode transparencyMode) {
     this(context, null, renderMode, transparencyMode);
   }
 
   /**
    * Constructs a {@code FlutterSurfaceView} in an XML-inflation-compliant manner.
-   *
-   * // TODO(mattcarroll): expose renderMode in XML when build system supports R.attr
+   * <p>
+   * {@code FlutterView} requires an {@code Activity} instead of a generic {@code Context}
+   * to be compatible with {@link PlatformViewsController}.
    */
+   // TODO(mattcarroll): expose renderMode in XML when build system supports R.attr
   public FlutterView(@NonNull Context context, @Nullable AttributeSet attrs) {
     this(context, attrs, null, null);
   }
@@ -367,6 +382,21 @@ public InputConnection onCreateInputConnection(@NonNull EditorInfo outAttrs) {
     return textInputPlugin.createInputConnection(this, outAttrs);
   }
 
+  /**
+   * Allows a {@code View} that is not currently the input connection target to invoke commands on
+   * the {@link android.view.inputmethod.InputMethodManager}, which is otherwise disallowed.
+   * <p>
+   * Returns true to allow non-input-connection-targets to invoke methods on
+   * {@code InputMethodManager}, or false to exclusively allow the input connection target to invoke
+   * such methods.
+   */
+  @Override
+  public boolean checkInputConnectionProxy(View view) {
+    return flutterEngine != null
+        ? flutterEngine.getPlatformViewsController().checkInputConnectionProxy(view)
+        : super.checkInputConnectionProxy(view);
+  }
+
   /**
    * Invoked when key is released.
    *
@@ -511,7 +541,9 @@ private void resetWillNotDraw(boolean isAccessibilityEnabled, boolean isTouchExp
    * See {@link #detachFromFlutterEngine()} for information on how to detach from a
    * {@link FlutterEngine}.
    */
-  public void attachToFlutterEngine(@NonNull FlutterEngine flutterEngine) {
+  public void attachToFlutterEngine(
+      @NonNull FlutterEngine flutterEngine
+  ) {
     Log.d(TAG, "Attaching to a FlutterEngine: " + flutterEngine);
     if (isAttachedToFlutterEngine()) {
       if (flutterEngine == this.flutterEngine) {
@@ -537,7 +569,7 @@ public void attachToFlutterEngine(@NonNull FlutterEngine flutterEngine) {
     textInputPlugin = new TextInputPlugin(
         this,
         this.flutterEngine.getDartExecutor(),
-        null
+        this.flutterEngine.getPlatformViewsController()
     );
     androidKeyProcessor = new AndroidKeyProcessor(
         this.flutterEngine.getKeyEventChannel(),
@@ -549,16 +581,18 @@ public void attachToFlutterEngine(@NonNull FlutterEngine flutterEngine) {
         flutterEngine.getAccessibilityChannel(),
         (AccessibilityManager) getContext().getSystemService(Context.ACCESSIBILITY_SERVICE),
         getContext().getContentResolver(),
-        // TODO(mattcaroll): plumb the platform views controller to the accessibility bridge.
-        // https://github.com/flutter/flutter/issues/29618
-        null
+        this.flutterEngine.getPlatformViewsController()
     );
     accessibilityBridge.setOnAccessibilityChangeListener(onAccessibilityChangeListener);
     resetWillNotDraw(
         accessibilityBridge.isAccessibilityEnabled(),
         accessibilityBridge.isTouchExplorationEnabled()
     );
 
+    // Connect AccessibilityBridge to the PlatformViewsController within the FlutterEngine.
+    // This allows platform Views to hook into Flutter's overall accessibility system.
+    this.flutterEngine.getPlatformViewsController().attachAccessibilityBridge(accessibilityBridge);
+
     // Inform the Android framework that it should retrieve a new InputConnection
     // now that an engine is attached.
     // TODO(mattcarroll): once this is proven to work, move this line ot TextInputPlugin
@@ -597,6 +631,9 @@ public void detachFromFlutterEngine() {
       listener.onFlutterEngineDetachedFromFlutterView();
     }
 
+    // Disconnect the FlutterEngine's PlatformViewsController from the AccessibilityBridge.
+    flutterEngine.getPlatformViewsController().detachAccessibiltyBridge();
+
     // Disconnect and clean up the AccessibilityBridge.
     accessibilityBridge.release();
     accessibilityBridge = null;

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

@@ -29,6 +29,7 @@
 import io.flutter.embedding.engine.systemchannels.SettingsChannel;
 import io.flutter.embedding.engine.systemchannels.SystemChannel;
 import io.flutter.embedding.engine.systemchannels.TextInputChannel;
+import io.flutter.plugin.platform.PlatformViewsController;
 
 /**
  * A single Flutter execution environment.
@@ -88,6 +89,11 @@ public class FlutterEngine implements LifecycleOwner {
   @NonNull
   private final TextInputChannel textInputChannel;
 
+  // Platform Views.
+  @NonNull
+  private final PlatformViewsController platformViewsController;
+
+  // Engine Lifecycle.
   @NonNull
   private final Set<EngineLifecycleListener> engineLifecycleListeners = new HashSet<>();
   @NonNull
@@ -138,6 +144,8 @@ public FlutterEngine(@NonNull Context context) {
     systemChannel = new SystemChannel(dartExecutor);
     textInputChannel = new TextInputChannel(dartExecutor);
 
+    platformViewsController = new PlatformViewsController();
+
     androidLifecycle = new FlutterEngineAndroidLifecycle(this);
     this.pluginRegistry = new FlutterEnginePluginRegistry(
       context.getApplicationContext(),
@@ -300,6 +308,15 @@ public PluginRegistry getPlugins() {
     return pluginRegistry;
   }
 
+  /**
+   * {@code PlatformViewsController}, which controls all platform views running within
+   * this {@code FlutterEngine}.
+   */
+  @NonNull
+  public PlatformViewsController getPlatformViewsController() {
+    return platformViewsController;
+  }
+
   @NonNull
   public ActivityControlSurface getActivityControlSurface() {
     return pluginRegistry;