How to pass a string value from a class to another in the same activity in Flutter?

Question

// I cant find a way to pass a string from a class to another. They are both in the same screen and i want to pass the index from a pageview on class to another. Any help would be grateful!

//on the first class//


            onPageChanged: (int index) {
            _sendDataToAnotherClass(context, index);
            _currentPageNotifier.value = index;
          }),
      ),
    );
}


  void _sendDataToAnotherClass(BuildContext context, int index) {
    final String texttosend = index.toString();
    Navigator.of(context).push(
        MaterialPageRoute(
            builder: (context) {
              return new personaname(text: texttosend);
            }

        ));
  }


//on the second class//

 final String text ;
 personaname({Key key, @required this.text}) : super(key: key);

please edit your question and use the code format tool. Reading code as a single string like the comment section does is a bit of a task — Adrian Murray, Jun 03 '19 at 14:51
You said that these are on the same screen but I see a navigator.push() call which means it can't be on the same screen. — Adrian Murray, Jun 03 '19 at 14:57
They are on the same screen but in different dart files. The navigator.push() is the only solution i have found and its not working. — George Kordatos, Jun 03 '19 at 14:58
@GeorgeKordatos how do you import the other file is it by the File Path in lib folder — Mohamed Elrashid, Jun 03 '19 at 15:17
@AdrianMurray thanks, if he use difrent file your code will not work with file name import , it's a dart lang thing try it you self use 2 files — Mohamed Elrashid, Jun 03 '19 at 20:44
I ran into this problem back in beta but it hasn't made a difference since 1.0. — Adrian Murray, Jun 03 '19 at 20:48

Adrian Murray · Answer 1 · 2019-06-03T15:14:07.560

if your personaname is a class (just fyi if that is indeed a class the proper format is to capitalize the first letters of each word - PersonaName), and that class is a stateful widget you could pass the data down to it and do a call within the state to override the didUpdateWidget method to setState on data changes. This would mean you don't need the value notifier.

Something like this might do what you're looking for:

class PageViewHolder extends StatelessWidget{

  PersonaName name = PersonaName(text: 'text',);

  @override
  Widget build(BuildContext context) {

    return PageView(
      onPageChanged: (p){
        var textToSend = 'do logic to decide name';
        name.text = textToSend;
      },
    );
  }

}


class PersonaName extends StatefulWidget{
  String text;

  PersonaName({Key key, this.text}) : super(key: key);

  @override
  State<StatefulWidget> createState() =>_PersonaName();
}

class _PersonaName extends State<PersonaName>{



  @override
  Widget build(BuildContext context) {
    return Text(widget.text);
  }

  @override
  void didUpdateWidget(PersonaName oldWidget) {
    super.didUpdateWidget(oldWidget);
    if(widget.text != oldWidget.text){
      setState(() {});
    }
  }
}

Great this should work. The only problem is that the String text in the PersonaName class is null. — George Kordatos, Jun 03 '19 at 15:38
I only provided the bare minimum to pass the data. How you construct your classes is up to you. If this solves the passing of data question please mark it as solved. — Adrian Murray, Jun 03 '19 at 15:40
I don't know how you implemented the suggestions so I can't tell you what's going wrong. — Adrian Murray, Jun 03 '19 at 16:14

How to pass a string value from a class to another in the same activity in Flutter?

1 Answers1