By Suragch


2018-12-20 01:21:07 8 Comments

As I'm learning Flutter I've come to navigation. I want to pass data between screens similarly to passing data between Activities in Android and passing data between View Controllers in iOS. How do I do it in Flutter?

Related questions:

8 comments

@Prajwal Shinde 2020-05-08 17:56:23

Navigators in Flutter are similar to the Intent in Android. There are two classes we are dealing with FirstScreen and SecondScreen.

In order to pass the data between the first screen to second do the following: First of all add parameter in the SecondScreen class constructor

Now in the FirstScreen class provide the parameter

Navigator.push(context, MaterialPageRoute(builder: (context)=>SecondScreen(key_name:"Desired Data"));

So in the above line the "key_name" is the name of the parameter given in the SecondScreen class. The "Desired Data" is data should be passed through the key to the SecondScreen class.

That's it you are done!!!

@Anil Kumar 2020-04-17 08:42:23

1) From where you want to push :

onPressed: () async {
                        await Navigator.pushNamed(context, '/edit',
                            arguments: userData);
                        setState(() {
                          userData = userData;
                        });}

2) From Where you want to pop :

    void updateData() async{
    WorldTime instance = locations;
    await instance.getData();
    Navigator.pop(context, userData);
  }

@Bijendra Singh 2020-02-09 13:51:47

Get Perfect Solution :

  1. From 1st Screen navigate to others as:

    Navigator.pushNamed(context, "second",arguments: {"name" : 
      "Bijendra", "rollNo": 65210});
    },
    
  2. On Second Screen in build method get as :

    @override
    Widget build(BuildContext context) {
        final  Map<String, Object>rcvdData = ModalRoute.of(context).settings.arguments;
        print("rcvd fdata ${rcvdData['name']}");
        print("rcvd fdata ${rcvdData}");
    
        return Scaffold(appBar: AppBar(title: Text("Second")),
          body: Container(child: Column(children: <Widget>[
          Text("Second"),
        ],),),);
    
    }
    

@praveenb 2020-04-28 16:13:03

hi, anyway, to reset arguments, after loading second widget. Thanks

@serg 2019-12-25 13:45:08

Answers above are useful for a small app, but if you want to remove the headache of continuously worrying about a widgets state, Google presented the Provider package. https://pub.dev/packages/provider

Have a look into that one, or watch these videos from Andrea Bizzotto: https://www.youtube.com/watch?v=MkFjtCov62g // Provider: The Essential Guide https://www.youtube.com/watch?v=O71rYKcxUgA&t=258s // Provider: Introduction

Learn how to use the Provider package, and you are set for life :)

@Mano Haran 2020-05-24 23:48:35

Not many people realised how important this reply is. Thanks for the video links :)

@Varsha 2019-12-25 07:48:47

First Screen : //send data to second screen

 Navigator.push(context, MaterialPageRoute(builder: (context) {
                          return WelcomeUser(usernameController.text);

                          }));

Second Screen : //fetch data from first screen

 final String username;
  WelcomeUser(this.username);

//use data to display

body: Container(
    child: Center(
      child: Text("Welcome "+widget.username,
      textAlign: TextAlign.center,
      ),
    ),
  ),

@JAMSHAID 2020-01-18 14:15:08

it produces an error Unhandled Exception: NoSuchMethodError: The getter 'focusScopeNode' was called on null.

@JAMSHAID 2020-01-18 14:30:02

I am in async function

@Mahmoud salah eldien saber 2019-06-24 22:19:46

This solution is very easy by passing variables in constructor:

first page:

Navigator.of(context).push(MaterialPageRoute(builder:(context)=>SecondPage('something')));

second page:

class SecondPage extends StatefulWidget {
  String something;
  SecondPage(this.something);
  @override
  State<StatefulWidget> createState() {
    return SecondPageState(this.something);
  }
}
class SecondPageState extends State<SecondPage> {
  String something;
  SecondPageState(this.something);
  @override
  Widget build(BuildContext context) {
   return Scaffold(
    appBar: AppBar(
    //now you have passing variable
    title: Text(something),
   ),
   ...
  }

@maheshmnj 2019-11-11 07:50:51

you dont need to pass data to state here return SecondPageState(this.something); you can access data in SecondPageState as widget.something directly without passing to state;

@user11065582 2019-03-06 06:11:59

Easiest way

FirstPage.dart

 Navigator.push(
          context,
          MaterialPageRoute(
              builder: (context) => PasswordRoute(usernameController)));

//usernameController is String value,If you want to pass multiple values add all

SecondPage.dart

class PasswordRoute extends StatefulWidget {
  final String usernameController;//if you have multiple values add here
PasswordRoute(this.usernameController, {Key key}): super(key: key);//add also..example this.abc,this...

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

class _PasswordPageState extends State<PasswordRoute> {
 @override
  Widget build(BuildContext context) {
...child: Text(widget.usernameController);
}
}

@Ian Ronk 2020-02-22 13:57:59

widget.usernameController worked for me, but not just usernameController, as @Suragch said, I don't know if that is because of a different method or a newer flutter version

@Suragch 2018-12-20 01:21:07

This answer will cover both passing data forward and passing data back. Unlike Android Activities and iOS ViewControllers, different screens in Flutter are just widgets. Navigating between them involves creating something called a route and using the Navigator to push and pop the routes on and off the stack.

Passing data forward to the next screen

enter image description here

To send data to the next screen you do the following things:

  1. Make the SecondScreen constructor take a parameter for the type of data that you want to send to it. In this particular example, the data is defined to be a String value and is set here with this.text.

    class SecondScreen extends StatelessWidget {
      final String text;
      SecondScreen({Key key, @required this.text}) : super(key: key);
    
      ...
    
  2. Then use the Navigator in the FirstScreen widget to push a route to the SecondScreen widget. You put the data that you want to send as a parameter in its constructor.

    Navigator.push(
        context,
        MaterialPageRoute(
          builder: (context) => SecondScreen(text: 'Hello',),
        ));
    

The full code for main.dart is here:

import 'package:flutter/material.dart';

void main() {
  runApp(MaterialApp(
    title: 'Flutter',
    home: FirstScreen(),
  ));
}

class FirstScreen extends StatefulWidget {
  @override
  _FirstScreenState createState() {
    return _FirstScreenState();
  }
}

class _FirstScreenState extends State<FirstScreen> {

  // this allows us to access the TextField text
  TextEditingController textFieldController = TextEditingController();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('First screen')),
      body: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [

          Padding(
            padding: const EdgeInsets.all(32.0),
            child: TextField(
              controller: textFieldController,
              style: TextStyle(
                fontSize: 24,
                color: Colors.black,
              ),
            ),
          ),

          RaisedButton(
            child: Text(
              'Go to second screen',
              style: TextStyle(fontSize: 24),
            ),
            onPressed: () {
              _sendDataToSecondScreen(context);
            },
          )

        ],
      ),
    );
  }

  // get the text in the TextField and start the Second Screen
  void _sendDataToSecondScreen(BuildContext context) {
    String textToSend = textFieldController.text;
    Navigator.push(
        context,
        MaterialPageRoute(
          builder: (context) => SecondScreen(text: textToSend,),
        ));
  }
}

class SecondScreen extends StatelessWidget {
  final String text;

  // receive data from the FirstScreen as a parameter
  SecondScreen({Key key, @required this.text}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Second screen')),
      body: Center(
        child: Text(
          text,
          style: TextStyle(fontSize: 24),
        ),
      ),
    );
  }
}

Passing data back to the previous screen

enter image description here

When passing data back you need to do the following things:

  1. In the FirstScreen, use the Navigator to push (start) the SecondScreen in an async method and wait for the result that it will return when it finishes.

    final result = await Navigator.push(
        context,
        MaterialPageRoute(
          builder: (context) => SecondScreen(),
        ));
    
  2. In the SecondScreen, include the data that you want to pass back as a parameter when you pop the Navigator.

    Navigator.pop(context, 'Hello');
    
  3. Then in the FirstScreen the await will finish and you can use the result.

    setState(() {
      text = result;
    });
    

Here is the complete code for main.dart for your reference.

import 'package:flutter/material.dart';

void main() {
  runApp(MaterialApp(
    title: 'Flutter',
    home: FirstScreen(),
  ));
}

class FirstScreen extends StatefulWidget {
  @override
  _FirstScreenState createState() {
    return _FirstScreenState();
  }
}

class _FirstScreenState extends State<FirstScreen> {

  String text = 'Text';

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('First screen')),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [

            Padding(
              padding: const EdgeInsets.all(32.0),
              child: Text(
                text,
                style: TextStyle(fontSize: 24),
              ),
            ),

            RaisedButton(
              child: Text(
                'Go to second screen',
                style: TextStyle(fontSize: 24),
              ),
              onPressed: () {
                _awaitReturnValueFromSecondScreen(context);
              },
            )

          ],
        ),
      ),
    );
  }

  void _awaitReturnValueFromSecondScreen(BuildContext context) async {

    // start the SecondScreen and wait for it to finish with a result
    final result = await Navigator.push(
        context,
        MaterialPageRoute(
          builder: (context) => SecondScreen(),
        ));

    // after the SecondScreen result comes back update the Text widget with it
    setState(() {
      text = result;
    });
  }
}

class SecondScreen extends StatefulWidget {
  @override
  _SecondScreenState createState() {
    return _SecondScreenState();
  }
}

class _SecondScreenState extends State<SecondScreen> {
  // this allows us to access the TextField text
  TextEditingController textFieldController = TextEditingController();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Second screen')),
      body: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [

          Padding(
            padding: const EdgeInsets.all(32.0),
            child: TextField(
              controller: textFieldController,
              style: TextStyle(
                fontSize: 24,
                color: Colors.black,
              ),
            ),
          ),

          RaisedButton(
            child: Text(
              'Send text back',
              style: TextStyle(fontSize: 24),
            ),
            onPressed: () {
              _sendDataBack(context);
            },
          )

        ],
      ),
    );
  }

  // get the text in the TextField and send it back to the FirstScreen
  void _sendDataBack(BuildContext context) {
    String textToSendBack = textFieldController.text;
    Navigator.pop(context, textToSendBack);
  }
}

@MrLalatg 2019-05-18 23:28:36

How can I do this if my second page is a stateful widget to? I can't call setState in the constructor...

@Nagaraj Alagusudaram 2019-05-27 23:06:03

@MrLalatg use "widget.$variable_name" to get the data if you're using a stateful widget. String tempText = widget.text

@user3245268 2019-09-19 19:37:23

Is it okay to send arbitrary large amount of data like this? I am aware that in Android, passing data via "Activities" should be kept minimal.

@Suragch 2019-09-20 01:52:28

@user3245268, I'm not aware of any restriction on the amount of data. I would assume, though, that if it is an extremely large amount of data then you would just query the database or something from the second screen rather than pass it from the first screen.

Related Questions

Sponsored Content

4 Answered Questions

[SOLVED] Passing Data to a Stateful Widget

  • 2018-06-12 13:43:39
  • Mojachiee
  • 56726 View
  • 109 Score
  • 4 Answer
  • Tags:   dart flutter

1 Answered Questions

Make a Not Full Screen Flutter Route

  • 2018-06-30 11:53:52
  • behzad.robot
  • 942 View
  • 1 Score
  • 1 Answer
  • Tags:   dart flutter

3 Answered Questions

[SOLVED] Passing data to StatefulWidget and accessing it in it's state in Flutter

  • 2018-05-11 08:16:50
  • moonvader
  • 58667 View
  • 115 Score
  • 3 Answer
  • Tags:   dart flutter

1 Answered Questions

Flutter navigation best practice

2 Answered Questions

[SOLVED] Flutter: Passing multiple data between screens

  • 2019-06-20 03:04:06
  • Jun Dalisay
  • 1599 View
  • 1 Score
  • 2 Answer
  • Tags:   flutter

1 Answered Questions

[SOLVED] Passing data between screen

  • 2019-06-18 12:16:49
  • Silva
  • 71 View
  • 0 Score
  • 1 Answer
  • Tags:   flutter dart

1 Answered Questions

1 Answered Questions

[SOLVED] How to navigate between flutter screen to native(android/ios) screens

  • 2017-02-15 11:05:54
  • Ashrith K S
  • 1430 View
  • 1 Score
  • 1 Answer
  • Tags:   flutter

Sponsored Content