initExpensiveAndroidView method Null safety

ExpensiveAndroidViewController initExpensiveAndroidView(
  1. {required int id,
  2. required String viewType,
  3. required TextDirection layoutDirection,
  4. dynamic creationParams,
  5. MessageCodec? creationParamsCodec,
  6. VoidCallback? onFocus}

Creates a controller for a new Android view.

id is an unused unique identifier generated with platformViewsRegistry.

viewType is the identifier of the Android view type to be created, a factory for this view type must have been registered on the platform side. Platform view factories are typically registered by plugin code. Plugins can register a platform view factory with PlatformViewRegistry#registerViewFactory.

creationParams will be passed as the args argument of PlatformViewFactory#create

creationParamsCodec is the codec used to encode creationParams before sending it to the platform side. It should match the codec passed to the constructor of PlatformViewFactory. This is typically one of: StandardMessageCodec, JSONMessageCodec, StringCodec, or BinaryCodec.

onFocus is a callback that will be invoked when the Android View asks to get the input focus.

The Android view will only be created after AndroidViewController.setSize is called for the first time.

The id,viewType, and layoutDirection parameters must not be null. If creationParams is non null then creationParamsCodec must not be null.

When this factory is used, the Android view and Flutter widgets are composed at the Android view hierarchy level. This is only useful if the view is a Android SurfaceView. However, using this method has a performance cost on devices that run below 10, or underpowered devices. In most situations, you should use initAndroidView.


static ExpensiveAndroidViewController initExpensiveAndroidView({
  required int id,
  required String viewType,
  required TextDirection layoutDirection,
  dynamic creationParams,
  MessageCodec<dynamic>? creationParamsCodec,
  VoidCallback? onFocus,
}) {
  final ExpensiveAndroidViewController controller = ExpensiveAndroidViewController._(
    viewId: id,
    viewType: viewType,
    layoutDirection: layoutDirection,
    creationParams: creationParams,
    creationParamsCodec: creationParamsCodec,

  _instance._focusCallbacks[id] = onFocus ?? () {};
  return controller;