I have a widget that is going to use the flutter_sound package to record audio: https://flutter-sound.canardoux.xyz/readme.html

I set up the stateless widget, then used Android Studio's context actions to convert it to a stateful one. Then, I added the await keyword to match this example from the documentation: https://flutter-sound.canardoux.xyz/tau_api_recorder_open_audio_session.html

Android studio then gave an error that said I needed to convert the widget's build function to an async function. When I did so (via the context action), it gave another error: '_MsgInputState.build' ('Future<Widget> Function(BuildContext)') isn't a valid override of 'State.build' ('Widget Function(BuildContext)')

class _MsgInputState extends State<MsgInput> {
  final database = FirebaseDatabase.instance.reference();

  final auth = AuthService();

  @override
  Future<Widget> build(BuildContext context) async { //error points to the 'build' keyword here
    final messageDao = MessageDao(groupIDPath: widget.groupIDPath);
    final groupChatRef = database.child('groupChats/0exUS3P2XKFQ007TIMmm'); //TODO: Remove hardcoded value
    final messageController = TextEditingController();
    var myRecorder = await FlutterSoundRecorder().openAudioSession();

    @override
    void dispose() {
      myRecorder.closeAudioSession();
      super.dispose();
    }

    return Scaffold(
    ...
    )
  }
}

CodePudding user response：

Because build method should return Widget, not Future. Either use FutureBuilderor StreamBuilderfor such cases.

FutureBuilder

StreamBuilder

CodePudding user response：

The main problem is you have incorrect structure for your StatefulWidget class. See https://docs.flutter.dev/development/ui/interactive for details.

It should be something like this (read the comments for reason):

class MsgInput extends StatefulWidget {
  const MsgInput({Key? key}) : super(key: key);

  @override
  _MsgInputState createState() => _MsgInputState();
}

class _MsgInputState extends State<MsgInput> {

  // declaration and initialization of variables
  final messageDao = MessageDao(groupIDPath: widget.groupIDPath);
  final groupChatRef = database.child('groupChats/0exUS3P2XKFQ007TIMmm'); //TODO: Remove hardcoded value
  final messageController = TextEditingController();
  late var myRecorder;
  
  @override
  void initState() {
    super.initState();

    // Or initilize variables with their own method, especially a future one.
    initialize(); 
  }


  // build should return Widget
  @override
  Widget build(BuildContext context) {
    // Do not place variables here because Flutter calls the build() method
    // every time it needs to change anything in the view, and this
    // happens surprisingly often. 

    // Return your widget, not future widget.
    return Scaffold(
    ...
    );
  }

  // dispose must be member of _MsgInputState.
  @override
  void dispose() {
    myRecorder.closeAudioSession();
    super.dispose();
  }

  // specific method to initialize variables.
  void initialize() async {
    myRecorder = await FlutterSoundRecorder().openAudioSession();
  }
}