As we know, flutter can call Android or iOS api by plugin, I had written some widgets, Android and iOS native widgets, can I use those widgets in flutter, just like in react native. Thanks.
3 Answers
Yes, you can.
With https://api.flutter.dev/flutter/widgets/AndroidView-class.html (Android) and https://api.flutter.dev/flutter/widgets/UiKitView-class.html (iOS)
Google is using this two Widgets to render WebViews and Maps on those platforms. See: https://pub.dev/packages/webview_flutter and https://pub.dev/packages/google_maps_flutter
It is definitely not easy to use, but it is possible.
Comments
If you are looking for App Widgets that are shown on android desktop, then it is possible to implement such Widgets with native code and use it with flutter.
I'll not completely deny that it is not possible to bridge between native widget and flutter's dart code, but I can say the possibility is yet to be discovered.
Here is the simple App Widget created natively and used with flutter.
If you wanted to look into the source code, and build app from source. Here it is.
Hope that helped!

App Widgetsof android andToday's extensionsof IOS?