fix platformview bug

android/src/main/java/com/idlefish/flutterboost/XFlutterView.java

@@ -448,6 +448,9 @@ public class XFlutterView extends FrameLayout {
 
     this.flutterEngine = flutterEngine;
 
+    // initialize PlatformViewsController
+    this.flutterEngine.getPluginRegistry().getPlatformViewsController().attach(getContext(),flutterEngine.getRenderer(),flutterEngine.getDartExecutor());
+
     // Instruct our FlutterRenderer that we are now its designated RenderSurface.
     this.flutterEngine.getRenderer().attachToRenderSurface(renderSurface);
 
@@ -506,6 +509,10 @@ public class XFlutterView extends FrameLayout {
     }
     Log.d(TAG, "Detaching from Flutter Engine");
 
+    // detach platformviews in page in case memory leak
+    flutterEngine.getPluginRegistry().getPlatformViewsController().detach();
+    flutterEngine.getPluginRegistry().getPlatformViewsController().onFlutterViewDestroyed();
+
     // Inform the Android framework that it should retrieve a new InputConnection
     // now that the engine is detached. The new InputConnection will be null, which
     // signifies that this View does not process input (until a new engine is attached).