I am fetching data from api in getSmartTags()

And if error occurs, I want to show the dialog.

I made the code below but this error comes.

lib/main.dart:1218:14: Error: Undefined name 'context'. context: context, ^^^^^^^

@override
Widget build(BuildContext context) {

context is in build function, but I want to show the alert dialog not in build function, is it possible?

Future<void> _showMyDialog() async {
  return showDialog<void>(
    context: context,
    barrierDismissible: false, // user must tap button!
    builder: (BuildContext context) {
      return AlertDialog(
        title: const Text('AlertDialog Title'),
        content: SingleChildScrollView(
          child: ListBody(
            children: const <Widget>[
              Text('This is a demo alert dialog.'),
              Text('Would you like to approve of this message?'),
            ],
          ),
        ),
        actions: <Widget>[
          TextButton(
            child: const Text('Approve'),
            onPressed: () {
              Navigator.of(context).pop();
            },
          ),
        ],
      );
    },
  );
}


Future getSmartTags() async {
    var url = Uri.https(apiServer,'/api/smarttags'); 
    try{
        var resp = await http.get(url);
        throw Exception();
    }catch(e){
        _showMyDialog();
    }
}

CodePudding user response：

Try this

//add context as parameter
Future<void> _showMyDialog(BuildContext context) async { 
    return showDialog<void>(
      context: context,
      barrierDismissible: false, // user must tap button!
      builder: (BuildContext context) {
        return AlertDialog(
          title: const Text('AlertDialog Title'),
          content: SingleChildScrollView(
            child: ListBody(
              children: const <Widget>[
                Text('This is a demo alert dialog.'),
                Text('Would you like to approve of this message?'),
              ],
            ),
          ),
          actions: <Widget>[
            TextButton(
              child: const Text('Approve'),
              onPressed: () {
                Navigator.of(context).pop();
              },
            ),
          ],
        );
      },
    );
  }



Future getSmartTags() async {
    var url = Uri.https(apiServer,'/api/smarttags'); 
    try{
        var resp = await http.get(url);
        throw Exception();
    }catch(e){
        _showMyDialog(context); //add this too
    }
}