+ * This method must not be invoked if {@code FlutterJNI} is already attached to native. + */ + @UiThread + public void attachToNative(boolean isBackgroundView) { + ensureRunningOnMainThread(); + ensureNotAttachedToNative(); + nativePlatformViewId = nativeAttach(this, isBackgroundView); + } + + private native long nativeAttach(FlutterJNI flutterJNI, boolean isBackgroundView); + + /** + * Detaches this {@code FlutterJNI} instance from Flutter's native engine, which precludes + * any further communication between Android code and Flutter's platform agnostic engine. + *
+ * This method must not be invoked if {@code FlutterJNI} is not already attached to native. + *
+ * Invoking this method will result in the release of all native-side resources that were + * setup during {@link #attachToNative(boolean)}, or accumulated thereafter. + *
+ * It is permissable to re-attach this instance to native after detaching it from native. + */ + @UiThread + public void detachFromNativeAndReleaseResources() { + ensureRunningOnMainThread(); + ensureAttachedToNative(); + nativeDestroy(nativePlatformViewId); + nativePlatformViewId = null; + } + + private native void nativeDestroy(long nativePlatformViewId); + + private void ensureNotAttachedToNative() { + if (nativePlatformViewId != null) { + throw new RuntimeException("Cannot execute operation because FlutterJNI is attached to native."); + } + } + + private void ensureAttachedToNative() { + if (nativePlatformViewId == null) { + throw new RuntimeException("Cannot execute operation because FlutterJNI is not attached to native."); + } + } + //------ End Native Attach/Detach Support ---- + + //----- Start Render Surface Support ----- /** * Sets the {@link FlutterRenderer.RenderSurface} delegate for the attached Flutter context. - * + *
* Flutter expects a user interface to exist on the platform side (Android), and that interface * is expected to offer some capabilities that Flutter depends upon. The {@link FlutterRenderer.RenderSurface} * interface represents those expectations. - * + *
* If an app includes a user interface that renders a Flutter UI then a {@link FlutterRenderer.RenderSurface} * should be set (this is the typical Flutter scenario). If no UI is being rendered, such as a * Flutter app that is running Dart code in the background, then no registration may be necessary. - * - * If no {@link FlutterRenderer.RenderSurface} is registered then related messages coming from + *
+ * If no {@link FlutterRenderer.RenderSurface} is registered, then related messages coming from * Flutter will be dropped (ignored). */ @UiThread @@ -136,6 +196,163 @@ public class FlutterJNI { this.renderSurface = renderSurface; } + /** + * Adds a {@link OnFirstFrameRenderedListener}, which receives a callback when Flutter's + * engine notifies {@code FlutterJNI} that the first frame of a Flutter UI has been rendered + * to the {@link Surface} that was provided to Flutter. + */ + @UiThread + public void addOnFirstFrameRenderedListener(@NonNull OnFirstFrameRenderedListener listener) { + ensureRunningOnMainThread(); + firstFrameListeners.add(listener); + } + + /** + * Removes a {@link OnFirstFrameRenderedListener} that was added with + * {@link #addOnFirstFrameRenderedListener(OnFirstFrameRenderedListener)}. + */ + @UiThread + public void removeOnFirstFrameRenderedListener(@NonNull OnFirstFrameRenderedListener listener) { + ensureRunningOnMainThread(); + firstFrameListeners.remove(listener); + } + + // Called by native to notify first Flutter frame rendered. + @SuppressWarnings("unused") + @UiThread + private void onFirstFrame() { + ensureRunningOnMainThread(); + if (renderSurface != null) { + renderSurface.onFirstFrameRendered(); + } + // TODO(mattcarroll): log dropped messages when in debug mode (https://github.com/flutter/flutter/issues/25391) + + for (OnFirstFrameRenderedListener listener : firstFrameListeners) { + listener.onFirstFrameRendered(); + } + } + + /** + * Call this method when a {@link Surface} has been created onto which you would like Flutter + * to paint. + *
+ * See {@link android.view.SurfaceHolder.Callback#surfaceCreated(SurfaceHolder)} for an example + * of where this call might originate. + */ + @UiThread + public void onSurfaceCreated(@NonNull Surface surface) { + ensureRunningOnMainThread(); + ensureAttachedToNative(); + nativeSurfaceCreated(nativePlatformViewId, surface); + } + + private native void nativeSurfaceCreated(long nativePlatformViewId, Surface surface); + + /** + * Call this method when the {@link Surface} changes that was previously registered with + * {@link #onSurfaceCreated(Surface)}. + *
+ * See {@link android.view.SurfaceHolder.Callback#surfaceChanged(SurfaceHolder, int, int, int)} + * for an example of where this call might originate. + */ + @UiThread + public void onSurfaceChanged(int width, int height) { + ensureRunningOnMainThread(); + ensureAttachedToNative(); + nativeSurfaceChanged(nativePlatformViewId, width, height); + } + + private native void nativeSurfaceChanged(long nativePlatformViewId, int width, int height); + + /** + * Call this method when the {@link Surface} is destroyed that was previously registered with + * {@link #onSurfaceCreated(Surface)}. + *
+ * See {@link android.view.SurfaceHolder.Callback#surfaceDestroyed(SurfaceHolder)} for an example + * of where this call might originate. + */ + @UiThread + public void onSurfaceDestroyed() { + ensureRunningOnMainThread(); + ensureAttachedToNative(); + nativeSurfaceDestroyed(nativePlatformViewId); + } + + private native void nativeSurfaceDestroyed(long nativePlatformViewId); + + /** + * Call this method to notify Flutter of the current device viewport metrics that are + * applies to the Flutter UI that is being rendered. + *
+ * This method should be invoked with initial values upon attaching to native. Then, + * it should be invoked any time those metrics change while {@code FlutterJNI} is + * attached to native. + */ + @UiThread + public void setViewportMetrics( + float devicePixelRatio, + int physicalWidth, + int physicalHeight, + int physicalPaddingTop, + int physicalPaddingRight, + int physicalPaddingBottom, + int physicalPaddingLeft, + int physicalViewInsetTop, + int physicalViewInsetRight, + int physicalViewInsetBottom, + int physicalViewInsetLeft + ) { + ensureRunningOnMainThread(); + ensureAttachedToNative(); + nativeSetViewportMetrics( + nativePlatformViewId, + devicePixelRatio, + physicalWidth, + physicalHeight, + physicalPaddingTop, + physicalPaddingRight, + physicalPaddingBottom, + physicalPaddingLeft, + physicalViewInsetTop, + physicalViewInsetRight, + physicalViewInsetBottom, + physicalViewInsetLeft + ); + } + + private native void nativeSetViewportMetrics( + long nativePlatformViewId, + float devicePixelRatio, + int physicalWidth, + int physicalHeight, + int physicalPaddingTop, + int physicalPaddingRight, + int physicalPaddingBottom, + int physicalPaddingLeft, + int physicalViewInsetTop, + int physicalViewInsetRight, + int physicalViewInsetBottom, + int physicalViewInsetLeft + ); + //----- End Render Surface Support ----- + + //------ Start Touch Interaction Support --- + /** + * Sends a packet of pointer data to Flutter's engine. + */ + @UiThread + public void dispatchPointerDataPacket(ByteBuffer buffer, int position) { + ensureRunningOnMainThread(); + ensureAttachedToNative(); + nativeDispatchPointerDataPacket(nativePlatformViewId, buffer, position); + } + + private native void nativeDispatchPointerDataPacket(long nativePlatformViewId, + ByteBuffer buffer, + int position); + //------ End Touch Interaction Support --- + + //------ Start Accessibility Support ----- /** * Sets the {@link AccessibilityDelegate} for the attached Flutter context. * @@ -186,24 +403,156 @@ public class FlutterJNI { // TODO(mattcarroll): log dropped messages when in debug mode (https://github.com/flutter/flutter/issues/25391) } - // Called by native to notify first Flutter frame rendered. - @SuppressWarnings("unused") - @UiThread - private void onFirstFrame() { - ensureRunningOnMainThread(); - if (renderSurface != null) { - renderSurface.onFirstFrameRendered(); - } - // TODO(mattcarroll): log dropped messages when in debug mode (https://github.com/flutter/flutter/issues/25391) - - for (OnFirstFrameRenderedListener listener : firstFrameListeners) { - listener.onFirstFrameRendered(); - } + /** + * Sends a semantics action to Flutter's engine, without any additional arguments. + */ + public void dispatchSemanticsAction(int id, @NonNull AccessibilityBridge.Action action) { + dispatchSemanticsAction(id, action, null); } + /** + * Sends a semantics action to Flutter's engine, with additional arguments. + */ + public void dispatchSemanticsAction(int id, @NonNull AccessibilityBridge.Action action, @Nullable Object args) { + ensureAttachedToNative(); + + ByteBuffer encodedArgs = null; + int position = 0; + if (args != null) { + encodedArgs = StandardMessageCodec.INSTANCE.encodeMessage(args); + position = encodedArgs.position(); + } + dispatchSemanticsAction(id, action.value, encodedArgs, position); + } + + /** + * Sends a semantics action to Flutter's engine, given arguments that are already encoded for + * the engine. + *
+ * To send a semantics action that has not already been encoded, see + * {@link #dispatchSemanticsAction(int, AccessibilityBridge.Action)} and + * {@link #dispatchSemanticsAction(int, AccessibilityBridge.Action, Object)}. + */ + @UiThread + public void dispatchSemanticsAction(int id, int action, ByteBuffer args, int argsPosition) { + ensureRunningOnMainThread(); + ensureAttachedToNative(); + nativeDispatchSemanticsAction(nativePlatformViewId, id, action, args, argsPosition); + } + + private native void nativeDispatchSemanticsAction( + long nativePlatformViewId, + int id, + int action, + ByteBuffer args, + int argsPosition + ); + + /** + * Instructs Flutter to enable/disable its semantics tree, which is used by Flutter to support + * accessibility and related behaviors. + */ + @UiThread + public void setSemanticsEnabled(boolean enabled) { + ensureRunningOnMainThread(); + ensureAttachedToNative(); + nativeSetSemanticsEnabled(nativePlatformViewId, enabled); + } + + private native void nativeSetSemanticsEnabled(long nativePlatformViewId, boolean enabled); + + // TODO(mattcarroll): figure out what flags are supported and add javadoc about when/why/where to use this. + @UiThread + public void setAccessibilityFeatures(int flags) { + ensureRunningOnMainThread(); + ensureAttachedToNative(); + nativeSetAccessibilityFeatures(nativePlatformViewId, flags); + } + + private native void nativeSetAccessibilityFeatures(long nativePlatformViewId, int flags); + //------ End Accessibility Support ---- + + //------ Start Texture Registration Support ----- + /** + * Gives control of a {@link SurfaceTexture} to Flutter so that Flutter can display that + * texture within Flutter's UI. + */ + @UiThread + public void registerTexture(long textureId, SurfaceTexture surfaceTexture) { + ensureRunningOnMainThread(); + ensureAttachedToNative(); + nativeRegisterTexture(nativePlatformViewId, textureId, surfaceTexture); + } + + private native void nativeRegisterTexture(long nativePlatformViewId, long textureId, SurfaceTexture surfaceTexture); + + /** + * Call this method to inform Flutter that a texture previously registered with + * {@link #registerTexture(long, SurfaceTexture)} has a new frame available. + *
+ * Invoking this method instructs Flutter to update its presentation of the given texture so that + * the new frame is displayed. + */ + @UiThread + public void markTextureFrameAvailable(long textureId) { + ensureRunningOnMainThread(); + ensureAttachedToNative(); + nativeMarkTextureFrameAvailable(nativePlatformViewId, textureId); + } + + private native void nativeMarkTextureFrameAvailable(long nativePlatformViewId, long textureId); + + /** + * Unregisters a texture that was registered with {@link #registerTexture(long, SurfaceTexture)}. + */ + @UiThread + public void unregisterTexture(long textureId) { + ensureRunningOnMainThread(); + ensureAttachedToNative(); + nativeUnregisterTexture(nativePlatformViewId, textureId); + } + + private native void nativeUnregisterTexture(long nativePlatformViewId, long textureId); + //------ Start Texture Registration Support ----- + + //------ Start Dart Execution Support ------- + /** + * Executes a Dart entrypoint. + *
+ * This can only be done once per JNI attachment because a Dart isolate can only be + * entered once. + */ + @UiThread + public void runBundleAndSnapshotFromLibrary( + @NonNull String[] prioritizedBundlePaths, + @Nullable String entrypointFunctionName, + @Nullable String pathToEntrypointFunction, + @NonNull AssetManager assetManager + ) { + ensureRunningOnMainThread(); + ensureAttachedToNative(); + nativeRunBundleAndSnapshotFromLibrary( + nativePlatformViewId, + prioritizedBundlePaths, + entrypointFunctionName, + pathToEntrypointFunction, + assetManager + ); + } + + private native void nativeRunBundleAndSnapshotFromLibrary( + long nativePlatformViewId, + @NonNull String[] prioritizedBundlePaths, + @Nullable String entrypointFunctionName, + @Nullable String pathToEntrypointFunction, + @NonNull AssetManager manager + ); + //------ End Dart Execution Support ------- + + //--------- Start Platform Message Support ------ /** * Sets the handler for all platform messages that come from the attached platform view to Java. - * + *
* Communication between a specific Flutter context (Dart) and the host platform (Java) is * accomplished by passing messages. Messages can be sent from Java to Dart with the corresponding * {@code FlutterJNI} methods: @@ -211,14 +560,13 @@ public class FlutterJNI { *
* {@code FlutterJNI} is also the recipient of all platform messages sent from its attached - * Flutter context (AKA platform view). {@code FlutterJNI} does not know what to do with these - * messages, so a handler is exposed to allow these messages to be processed in whatever manner is - * desired: - * + * Flutter context. {@code FlutterJNI} does not know what to do with these messages, so a handler + * is exposed to allow these messages to be processed in whatever manner is desired: + *
* {@code setPlatformMessageHandler(PlatformMessageHandler)} - * + *
* If a message is received but no {@link PlatformMessageHandler} is registered, that message will * be dropped (ignored). Therefore, when using {@code FlutterJNI} to integrate a Flutter context * in an app, a {@link PlatformMessageHandler} must be registered for 2-way Java/Dart communication @@ -249,254 +597,10 @@ public class FlutterJNI { // TODO(mattcarroll): log dropped messages when in debug mode (https://github.com/flutter/flutter/issues/25391) } - @UiThread - public void addEngineLifecycleListener(@NonNull EngineLifecycleListener engineLifecycleListener) { - ensureRunningOnMainThread(); - engineLifecycleListeners.add(engineLifecycleListener); - } - - @UiThread - public void removeEngineLifecycleListener(@NonNull EngineLifecycleListener engineLifecycleListener) { - ensureRunningOnMainThread(); - engineLifecycleListeners.remove(engineLifecycleListener); - } - - @UiThread - public void addOnFirstFrameRenderedListener(@NonNull OnFirstFrameRenderedListener listener) { - ensureRunningOnMainThread(); - firstFrameListeners.add(listener); - } - - @UiThread - public void removeOnFirstFrameRenderedListener(@NonNull OnFirstFrameRenderedListener listener) { - ensureRunningOnMainThread(); - firstFrameListeners.remove(listener); - } - - // TODO(mattcarroll): rename comments after refactor is done and their origin no longer matters (https://github.com/flutter/flutter/issues/25533) - //----- Start from FlutterView ----- - @UiThread - public void onSurfaceCreated(@NonNull Surface surface) { - ensureRunningOnMainThread(); - ensureAttachedToNative(); - nativeSurfaceCreated(nativePlatformViewId, surface); - } - - private native void nativeSurfaceCreated(long nativePlatformViewId, Surface surface); - - @UiThread - public void onSurfaceChanged(int width, int height) { - ensureRunningOnMainThread(); - ensureAttachedToNative(); - nativeSurfaceChanged(nativePlatformViewId, width, height); - } - - private native void nativeSurfaceChanged(long nativePlatformViewId, int width, int height); - - @UiThread - public void onSurfaceDestroyed() { - ensureRunningOnMainThread(); - ensureAttachedToNative(); - nativeSurfaceDestroyed(nativePlatformViewId); - } - - private native void nativeSurfaceDestroyed(long nativePlatformViewId); - - @UiThread - public void setViewportMetrics( - float devicePixelRatio, - int physicalWidth, - int physicalHeight, - int physicalPaddingTop, - int physicalPaddingRight, - int physicalPaddingBottom, - int physicalPaddingLeft, - int physicalViewInsetTop, - int physicalViewInsetRight, - int physicalViewInsetBottom, - int physicalViewInsetLeft - ) { - ensureRunningOnMainThread(); - ensureAttachedToNative(); - nativeSetViewportMetrics( - nativePlatformViewId, - devicePixelRatio, - physicalWidth, - physicalHeight, - physicalPaddingTop, - physicalPaddingRight, - physicalPaddingBottom, - physicalPaddingLeft, - physicalViewInsetTop, - physicalViewInsetRight, - physicalViewInsetBottom, - physicalViewInsetLeft - ); - } - - private native void nativeSetViewportMetrics( - long nativePlatformViewId, - float devicePixelRatio, - int physicalWidth, - int physicalHeight, - int physicalPaddingTop, - int physicalPaddingRight, - int physicalPaddingBottom, - int physicalPaddingLeft, - int physicalViewInsetTop, - int physicalViewInsetRight, - int physicalViewInsetBottom, - int physicalViewInsetLeft - ); - - @UiThread - public Bitmap getBitmap() { - ensureRunningOnMainThread(); - ensureAttachedToNative(); - return nativeGetBitmap(nativePlatformViewId); - } - - private native Bitmap nativeGetBitmap(long nativePlatformViewId); - - @UiThread - public void dispatchPointerDataPacket(ByteBuffer buffer, int position) { - ensureRunningOnMainThread(); - ensureAttachedToNative(); - nativeDispatchPointerDataPacket(nativePlatformViewId, buffer, position); - } - - private native void nativeDispatchPointerDataPacket(long nativePlatformViewId, - ByteBuffer buffer, - int position); - - public void dispatchSemanticsAction(int id, @NonNull AccessibilityBridge.Action action) { - dispatchSemanticsAction(id, action, null); - } - - public void dispatchSemanticsAction(int id, @NonNull AccessibilityBridge.Action action, @Nullable Object args) { - ensureAttachedToNative(); - - ByteBuffer encodedArgs = null; - int position = 0; - if (args != null) { - encodedArgs = StandardMessageCodec.INSTANCE.encodeMessage(args); - position = encodedArgs.position(); - } - dispatchSemanticsAction(id, action.value, encodedArgs, position); - } - - @UiThread - public void dispatchSemanticsAction(int id, int action, ByteBuffer args, int argsPosition) { - ensureRunningOnMainThread(); - ensureAttachedToNative(); - nativeDispatchSemanticsAction(nativePlatformViewId, id, action, args, argsPosition); - } - - private native void nativeDispatchSemanticsAction( - long nativePlatformViewId, - int id, - int action, - ByteBuffer args, - int argsPosition - ); - - @UiThread - public void setSemanticsEnabled(boolean enabled) { - ensureRunningOnMainThread(); - ensureAttachedToNative(); - nativeSetSemanticsEnabled(nativePlatformViewId, enabled); - } - - private native void nativeSetSemanticsEnabled(long nativePlatformViewId, boolean enabled); - - @UiThread - public void setAccessibilityFeatures(int flags) { - ensureRunningOnMainThread(); - ensureAttachedToNative(); - nativeSetAccessibilityFeatures(nativePlatformViewId, flags); - } - - private native void nativeSetAccessibilityFeatures(long nativePlatformViewId, int flags); - - @UiThread - public void registerTexture(long textureId, SurfaceTexture surfaceTexture) { - ensureRunningOnMainThread(); - ensureAttachedToNative(); - nativeRegisterTexture(nativePlatformViewId, textureId, surfaceTexture); - } - - private native void nativeRegisterTexture(long nativePlatformViewId, long textureId, SurfaceTexture surfaceTexture); - - @UiThread - public void markTextureFrameAvailable(long textureId) { - ensureRunningOnMainThread(); - ensureAttachedToNative(); - nativeMarkTextureFrameAvailable(nativePlatformViewId, textureId); - } - - private native void nativeMarkTextureFrameAvailable(long nativePlatformViewId, long textureId); - - @UiThread - public void unregisterTexture(long textureId) { - ensureRunningOnMainThread(); - ensureAttachedToNative(); - nativeUnregisterTexture(nativePlatformViewId, textureId); - } - - private native void nativeUnregisterTexture(long nativePlatformViewId, long textureId); - //------- End from FlutterView ----- - - // TODO(mattcarroll): rename comments after refactor is done and their origin no longer matters (https://github.com/flutter/flutter/issues/25533) - //------ Start from FlutterNativeView ---- - public boolean isAttached() { - return nativePlatformViewId != null; - } - - @UiThread - public void attachToNative(boolean isBackgroundView) { - ensureRunningOnMainThread(); - ensureNotAttachedToNative(); - nativePlatformViewId = nativeAttach(this, isBackgroundView); - } - - private native long nativeAttach(FlutterJNI flutterJNI, boolean isBackgroundView); - - @UiThread - public void detachFromNativeAndReleaseResources() { - ensureRunningOnMainThread(); - ensureAttachedToNative(); - nativeDestroy(nativePlatformViewId); - nativePlatformViewId = null; - } - - private native void nativeDestroy(long nativePlatformViewId); - - @UiThread - public void runBundleAndSnapshotFromLibrary( - @NonNull String[] prioritizedBundlePaths, - @Nullable String entrypointFunctionName, - @Nullable String pathToEntrypointFunction, - @NonNull AssetManager assetManager - ) { - ensureRunningOnMainThread(); - ensureAttachedToNative(); - nativeRunBundleAndSnapshotFromLibrary( - nativePlatformViewId, - prioritizedBundlePaths, - entrypointFunctionName, - pathToEntrypointFunction, - assetManager - ); - } - - private native void nativeRunBundleAndSnapshotFromLibrary( - long nativePlatformViewId, - @NonNull String[] prioritizedBundlePaths, - @Nullable String entrypointFunctionName, - @Nullable String pathToEntrypointFunction, - @NonNull AssetManager manager - ); - + /** + * Sends an empty reply (identified by {@code responseId}) from Android to Flutter over the given + * {@code channel}. + */ @UiThread public void dispatchEmptyPlatformMessage(String channel, int responseId) { ensureRunningOnMainThread(); @@ -514,6 +618,9 @@ public class FlutterJNI { int responseId ); + /** + * Sends a reply {@code message} from Android to Flutter over the given {@code channel}. + */ @UiThread public void dispatchPlatformMessage(String channel, ByteBuffer message, int position, int responseId) { ensureRunningOnMainThread(); @@ -539,6 +646,7 @@ public class FlutterJNI { int responseId ); + // TODO(mattcarroll): differentiate between channel responses and platform responses. @UiThread public void invokePlatformMessageEmptyResponseCallback(int responseId) { ensureRunningOnMainThread(); @@ -555,6 +663,7 @@ public class FlutterJNI { int responseId ); + // TODO(mattcarroll): differentiate between channel responses and platform responses. @UiThread public void invokePlatformMessageResponseCallback(int responseId, ByteBuffer message, int position) { ensureRunningOnMainThread(); @@ -577,10 +686,29 @@ public class FlutterJNI { ByteBuffer message, int position ); - //------ End from FlutterNativeView ---- + //------- End Platform Message Support ---- + + //----- Start Engine Lifecycle Support ---- + /** + * Adds the given {@code engineLifecycleListener} to be notified of Flutter engine lifecycle + * events, e.g., {@link EngineLifecycleListener#onPreEngineRestart()}. + */ + @UiThread + public void addEngineLifecycleListener(@NonNull EngineLifecycleListener engineLifecycleListener) { + ensureRunningOnMainThread(); + engineLifecycleListeners.add(engineLifecycleListener); + } + + /** + * Removes the given {@code engineLifecycleListener}, which was previously added using + * {@link #addOnFirstFrameRenderedListener(OnFirstFrameRenderedListener)}. + */ + @UiThread + public void removeEngineLifecycleListener(@NonNull EngineLifecycleListener engineLifecycleListener) { + ensureRunningOnMainThread(); + engineLifecycleListeners.remove(engineLifecycleListener); + } - // TODO(mattcarroll): rename comments after refactor is done and their origin no longer matters (https://github.com/flutter/flutter/issues/25533) - //------ Start from Engine --- // Called by native. @SuppressWarnings("unused") private void onPreEngineRestart() { @@ -588,19 +716,16 @@ public class FlutterJNI { listener.onPreEngineRestart(); } } - //------ End from Engine --- + //----- End Engine Lifecycle Support ---- - private void ensureNotAttachedToNative() { - if (nativePlatformViewId != null) { - throw new RuntimeException("Cannot execute operation because FlutterJNI is attached to native."); - } + @UiThread + public Bitmap getBitmap() { + ensureRunningOnMainThread(); + ensureAttachedToNative(); + return nativeGetBitmap(nativePlatformViewId); } - private void ensureAttachedToNative() { - if (nativePlatformViewId == null) { - throw new RuntimeException("Cannot execute operation because FlutterJNI is not attached to native."); - } - } + private native Bitmap nativeGetBitmap(long nativePlatformViewId); private void ensureRunningOnMainThread() { if (Looper.myLooper() != mainLooper) {