" Pass data from one page to another in Flutter "

Question

I know there are a ton of questions like these but I'm brand new to Flutter and I haven't found a post that suits my needs or maybe I'm just thinking about it wrong.

When developing with Flutter you might have seen that almost every screen requires to pass data from one screen to another and might also need to receive data back from another screen.

home.dart

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';

import 'applicationbar.dart';
import 'navigationdrawer.dart';
import 'bluetooth.dart';


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

class _HomeState extends State<Home> {
  String _string = '0m';  //so if _isFeetChecked is true in settings.dart this is '0ft'


  @override
  Widget build(BuildContext context) {

    return Scaffold(
      backgroundColor: Colors.grey[900],
      appBar: ApplicationBar(title: 'Luggage Follower'),
      drawer: NavigationDrawer(),
      body:Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: <Widget>[
          Padding(
            padding: const EdgeInsets.symmetric(vertical: 10,horizontal: 0),
            child: Text('good Status', style: Theme.of(context).textTheme.body2),
          ),
          Padding(
            padding: const EdgeInsets.symmetric(vertical: 10,horizontal: 0),
            child: Text('Paired', style: Theme.of(context).textTheme.body1),
          ),
          Padding(
            padding: const EdgeInsets.symmetric(vertical: 20,horizontal: 0),
            child: Divider(height: 3.0, color: Colors.pinkAccent, indent: 150, endIndent: 150),
          ),
          Padding(
            padding: const EdgeInsets.symmetric(vertical: 10,horizontal: 0),
            child: Text('Distance to Luggage', style: Theme.of(context).textTheme.body2),
          ),
          Padding(
            padding: const EdgeInsets.symmetric(vertical: 10,horizontal: 0),
            child: Text(_string, style: Theme.of(context).textTheme.body1), //dynamic text here
          ),
          Padding(
            padding: const EdgeInsets.symmetric(vertical: 10,horizontal: 0),
            child: LuggageFollow(),
          ),
        ],
      ),
    );
  }
}

settings.dart

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:audioplayers/audio_cache.dart';

import 'applicationbar.dart';
import 'navigationdrawer.dart';

class SettingsData {
  bool feet;
  bool metres;

  SettingsData({this.feet, this.metres});
}

class Settings extends StatefulWidget {
  @override
  _SettingsState createState() => _SettingsState();
}

class _SettingsState extends State<Settings> {
  static bool _isFeetChecked   = false;
  static bool _isMetersChecked = true;


  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: ApplicationBar(title: 'Settings'),
      drawer: NavigationDrawer(),
      body: Column(
          //crossAxisAlignment: CrossAxisAlignment.start,
          children: <Widget>[
            Padding(
              padding: EdgeInsets.symmetric(vertical: 20.0,horizontal: 20),
              child: Text('Distance Units')
            ),
            Divider(
              height: 3.0,
              color: Colors.pink,
            ),
            Padding(
              padding: EdgeInsets.symmetric(vertical: 20.0,horizontal: 0),
              child: CheckboxListTile(
                title: Text('Distance in feet', style: Theme.of(context).textTheme.body1),
                value: _isFeetChecked,
                onChanged: (bool value) {
                  setState(() {
                    _isFeetChecked = value; _isMetersChecked = !value;});
                },
                checkColor: Colors.white,
                activeColor: Colors.pink,
                subtitle: Text('1 foot ~ 0.3 metres',style: Theme.of(context).textTheme.display2),
              ),
            ),
            Padding(
              padding: EdgeInsets.symmetric(vertical: 20.0,horizontal: 0),
              child: CheckboxListTile(
                title: Text('Distance in metres', style: Theme.of(context).textTheme.body1),
                value: _isMetersChecked,
                onChanged: (bool value) {
                  setState(() { _isMetersChecked = value; _isFeetChecked = !value;updateData();});
                },
                checkColor: Colors.white,
                activeColor: Colors.pink,
                subtitle: Text('1 metre ~ 3 feet',style: Theme.of(context).textTheme.display2),
              ),
            ),
            Padding(
              padding: EdgeInsets.symmetric(vertical: 30.0,horizontal: 20),
              child: Text('Notifications')
            ),
            Divider(
                height: 3.0,
                color: Colors.pink,
            ),

              ),
            ),
          ],
      ),
    );
  }
}

Answer 1

Declare a Function in setting.dart file and Create Function with it's implementation in Home.dart file and pass to the setting.dart constructor. and call function from setting.dart page on your requirement to take pass data back.

you can follow flutter doc, that might help you a lot.

Answer 2

I suggest you use go_router recommended by flutter team

And refer: Flutter: go_router how to pass multiple parameters to other screen?

Answer 3

So, if you want to access data from one class to another then you just need to pass the variable in class constructor and you can use that in another class.

For example:

  class MyWidget extends StatelessWidget {
  final String? name;
  const MyWidget({super.key, this.name});
  @override
  Widget build(BuildContext context) {
    return Text(name!);
  }

You can use like this and in another class you just need to pass variable.

MyWidget(name: "Hi");