Provider updates variable, but the old value is passed into function that depend on it

Question

I am using a provider to store the value of input fields in a form. On save() method the TextFields call a method on the FormInputProvider that updates the variable inputAnn that holds updated input values.

_inputAnn is listening to the variable inputAnn of the provider.

When I call the function _upDateAnnouncementProvider I am adding the Announcement _inputAnn to a List of Announcements, that contains the form input information. However the value of _inputAnn is not updated by the inputAnn provider.

I tried Therefore inserting an asynchronous function: The 2 print messages outside the _upDateAnnouncementProvider function are updated, but the print message inside the async function remains the old one.

Can anyone help? If necessary I can give more of the code.

Thanks.

Widget build(BuildContext context) {
    var _inputAnn = Provider.of<FormInputProvider>(context).inputAnn;

    print('FORM SCREEN BUILD BEFORE : images:  ${_inputAnn.images.first}');

    Future<void> _upDateAnnouncementProvider() async {
      Future.delayed(Duration.zero).then((value) {
        Provider.of<Announcements>(context, listen: false).addItem(_inputAnn);
        print('INSIDE UPDATE PROVIDER: images:  ${_inputAnn.images.first}');
      });
    }

    print('FORM SCREEN BUILD: images:  ${_inputAnn.images.first}');
    loadHomeTypeList();
    return Scaffold(
      appBar: AppBar(
        title: Text('Aggiungi Annuncio'),
      ),
      body: Padding(
        padding: EdgeInsets.all(16.0),
        child: FormBody(
          scrollController: _scrollController,
          formKey: _formKey,
          getFormFields: () => _getFormFields(context, _inputAnn),
          saveForm: _saveForm,
          updateProvider: _upDateAnnouncementProvider,
        ),
      ),
    );
  }

Answer 1

By passing the Provider Object to the function outside of the build, the code now works correctly.

void _upDateAnnouncementProvider(FormInputProvider _inputAnnData) {
    Provider.of<Announcements>(context, listen: false)
        .addItem(_inputAnnData.inputAnn);
    print(
        'INSIDE UPDATE PROVIDER: images:  ${_inputAnnData.inputAnn.images.first}');
  }

  @override
  Widget build(BuildContext context) {
    final _inputAnnData = Provider.of<FormInputProvider>(context);
    var _inputAnn = _inputAnnData.inputAnn;

    print('FORM SCREEN BUILD: images:  ${_inputAnn.images.first}');

    loadHomeTypeList();
    return Scaffold(
      appBar: AppBar(
        title: Text('Aggiungi Annuncio'),
      ),
      body: Padding(
        padding: EdgeInsets.all(16.0),
        child: FormBody(
          scrollController: _scrollController,
          formKey: _formKey,
          getFormFields: () => _getFormFields(context, _inputAnn),
          saveForm: _saveForm,
          updateProvider: () => _upDateAnnouncementProvider(_inputAnnData),
        ),
      ),
    );
}