How do you change the value inside of a textfield flutter?

Question

I have a TextEditingController where if a user clicks a button it fills in with information. I can\'t seem to figure out how to change the text inside of a

Answer 1

Here is a full example where the parent widget controls the children widget. The parent widget updates the children widgets (Text and TextField) with a counter.

To update the Text widget, all you do is pass in the String parameter. To update the TextField widget, you need to pass in a controller, and set the text in the controller.

main.dart:

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Demo',
      home: Home(),
    );
  }
}

class Home extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: Text('Update Text and TextField demo'),
        ),
        body: ParentWidget());
  }
}

class ParentWidget extends StatefulWidget {
  @override
  _ParentWidgetState createState() => _ParentWidgetState();
}

class _ParentWidgetState extends State {
  int _counter = 0;
  String _text = 'no taps yet';
  var _controller = TextEditingController(text: 'initial value');

  void _handleTap() {
    setState(() {
      _counter = _counter + 1;
      _text = 'number of taps: ' + _counter.toString();
      _controller.text  = 'number of taps: ' + _counter.toString();
    });
  }

  @override
  Widget build(BuildContext context) {
    return Container(
      child: Column(children: [
        RaisedButton(
          onPressed: _handleTap,
          child: const Text('Tap me', style: TextStyle(fontSize: 20)),
        ),
        Text('$_text'),
        TextField(controller: _controller,),
      ]),
    );
  }
}