I'm using VoidCallback to call setState from child widget. But the callback function is not executing at all.

Below is my code in essence.

Child Widget:

class TextFormMentorHashtag extends StatefulWidget {
  const TextFormMentorHashtag({Key? key, required this.callback}) : super(key: key);

  final VoidCallback callback;

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

class _TextFormMentorHashtagState extends State<TextFormMentorHashtag> {

  @override
  Widget build(BuildContext context) {
  ...
    TextFormField(
      ...
      onChanged: (value) {
        if(_formKey.currentState!.validate()) {
          ...
          print('call callback');
          widget.callback;
        }
      }
    )
  }
}

parent widget:

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

  @override
  State<ApplyMentorPage> createState() => _ApplyMentorPageState();
}

class _ApplyMentorPageState extends State<ApplyMentorPage> {

  ...
  bool _disabled = true;

  @override
  Widget build(BuildContext context) {

    void callback() {
      print('callback called');
      setState(() {
        _disabled = !_mentorProvider.check();
      });
    }

    return Scaffold(
      ...
      child: Column(
        children: [
          TextFormMentorHashtag(callback: callback), 
          ...

// _disabled turns submit button on and off in the later code

When I run code and press child widget terminal prints 'call callback' but no 'callback called'. What am I missing?

CodePudding user response：

If your using TextFormField it has also ontap on it

TextFormField(
  onTap: () {
    print("am called");
  }
)

so you will is maybe like this

TextFormField(
  onTap: widget.calback
)

CodePudding user response：

You didn't call callback in your _TextFormMentorHashtagState. You should call it like widget.callback() or widget.callback.invoke().

Full code:

class _TextFormMentorHashtagState extends State<TextFormMentorHashtag> {

  @override
  Widget build(BuildContext context) {
  ...
    TextFormField(
      ...
      onChanged: (value) {
        if(_formKey.currentState!.validate()) {
          ...
          print('call callback');
          // or widget.callback()
          widget.callback.invoke();
        }
      }
    )
  }
}