I am trying to build a form for data capture, I have some instances where some form section have duplicate textfields. I want to reduce redundancy and copy data from the previously keyed in textfields like section 1 and have it appear on the duplicate textfield fields in section 20 of the same form. I have only managed the example below where you have to click on a button for the textfield to be pushed to another field. The code

import "package:flutter/material.dart";

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

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

class Home extends StatefulWidget {
@override
_HomeState createState() => _HomeState();
}

class _HomeState extends State<Home> {
final titleController = TextEditingController();
String text = "No Value Entered";

void _setText() {
    setState(() {
    text = titleController.text;
    });
}

@override
Widget build(BuildContext context) {
    return Scaffold(
    appBar: AppBar(
        title: Text('GeeksforGeeks'),
        backgroundColor: Colors.green,
    ),
    body: Column(
        children: [
        Padding(
            padding: const EdgeInsets.all(15),
            child: TextField(
            decoration: InputDecoration(labelText: 'Title'),
                
            controller: titleController,
                
            ),
        ),
        SizedBox(
            height: 8,
        ),
        RaisedButton(
            onPressed: _setText,
            child: Text('Submit'),
            elevation: 8,
        ),
        SizedBox(
            height: 20,
        ),
        Text(text),
        ],
    ),
    );
}
}

How can I achieve this by passing one textfield value to another textfield without pressing the submit button and not changing the state of the entire form?

CodePudding user response：

Register a listener on the TextEditingController on the initState method.

Then dispose of it on the dispose method.

Like this:

import "package:flutter/material.dart";

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

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

class Home extends StatefulWidget {
  @override
  _HomeState createState() => _HomeState();
}

class _HomeState extends State<Home> {
  final TextEditingController titleController = TextEditingController();
  String text = "No Value Entered";

  @override
  void initState() {
    titleController.addListener(_setText);
    super.initState();
  }

  @override
  void dispose() {
    titleController.dispose();
    super.dispose();
  }

  void _setText() {
    setState(() {
      text = titleController.text;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('GeeksforGeeks'),
        backgroundColor: Colors.green,
      ),
      body: Column(
        children: [
          Padding(
            padding: const EdgeInsets.all(15),
            child: TextField(
              decoration: InputDecoration(labelText: 'Title'),
              controller: titleController,
            ),
          ),
          SizedBox(
            height: 8,
          ),
          RaisedButton(
            onPressed: _setText,
            child: Text('Submit'),
            elevation: 8,
          ),
          SizedBox(
            height: 20,
          ),
          Text(text),
        ],
      ),
    );
  }
}

CodePudding user response：

You just need to add listeners to the respective textControllers as below:

class Home extends StatefulWidget {
  @override
  _HomeState createState() => _HomeState();
}

class _HomeState extends State<Home> {
  final titleController = TextEditingController();
  final titleController2 = TextEditingController();
  String text = "No Value Entered";

  @override
  void initState() {
    super.initState();
    titleController.addListener(() {
      setState(() {
        titleController2.text = titleController.text;
      });
    });

    titleController2.addListener(() {
      setState(() {
        titleController.text = titleController2.text;
      });
    });
  }

  @override
  void dispose() {
    titleController.dispose();
    titleController2.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('GeeksforGeeks'),
        backgroundColor: Colors.green,
      ),
      body: Column(
        children: [
          Padding(
            padding: const EdgeInsets.all(15),
            child: TextField(
              decoration: InputDecoration(labelText: 'Title'),
              controller: titleController,
            ),
          ),
          Padding(
            padding: const EdgeInsets.all(15),
            child: TextField(
              decoration: InputDecoration(labelText: 'Title'),
              controller: titleController2,
            ),
          ),
          SizedBox(
            height: 8,
          ),
          // RaisedButton(
          //   onPressed: _setText,
          //   child: Text('Submit'),
          //   elevation: 8,
          // ),
          // SizedBox(
          //   height: 20,
          // ),
          // Text(text),
        ],
      ),
    );
  }
}