There is a FirstScreen screen and there is a second SecondScreen called from the first screen, in the first screen a web socket is launched, data arrives on it, on the second screen, let's say there is a Text () widget into which you need to write data from the first screen when SecondScreen is already running. Which way to look?

CodePudding user response：

You can manage this issue using state management like provider or bloc

CodePudding user response：

var _channel;
var _screenShow = 1;

class FirstScreen extends StatefulWidget {
  FirstScreen();

  @override
  _FirstScreenState createState() => _FirstScreenState();
}

class _FirstScreenState extends State<FirstScreen> {
  void _serverListen() {
  _channel.stream.listen((message) {

    String res = message.trim();
    if (_screenShow == 1) {
      // update widjet SecondScreen      
    } else if (_screenShow == 2) {
      // update widjet ThirdScreen      
    } else if (_screenShow == 3) {
      // update widjet FourthScreen      
    } else {
      // update widjet FifthScreen      
    }
  },
    onDone: () {
      print('ws channel closed');
    },
    one rror: (error) {
      print('ws error $error');
    },
  );
}

@override
void initState() {
  super.initState();

  _channel = IOWebSocketChannel.connect(Uri.parse('ws address'));
  _serverListen();
}

@override
Widget build(BuildContext context) {
  return Scaffold(
    appBar: AppBar(
      title: Text('first screen'),
    ),
    body: Text('FirstScreen'),
    floatingActionButton: FloatingActionButton(
      elevation: 5,
      child: Icon(Icons.grid_on,),
      onPressed: ()  {
        Navigator.push(
          context,
          MaterialPageRoute(builder: (context) => SecondScreen()),
        );
      },
    ),
  );
}

// SecondScreen

class SecondScreen extends StatefulWidget {
  SecondScreen();

  @override
  _SecondScreenState createState() => _SecondScreenState();
}

class _SecondScreenState extends State<SecondScreen> {
  @override
  void initState() {
  super.initState();
}

@override
Widget build(BuildContext context) {
  return Scaffold(
    appBar: AppBar(
      title: Text('SecondScreen'),
    ),
    body: Text('update here from first screen'),
  );
}

}

CodePudding user response：

Use Getx Storage:

dependencies:
  get_storage: ^2.0.3

Example: In 1st Screen You Need to Store the value :

Initialize storage driver with await:

# main() async {   await
 GetStorage.init();   runApp(App()); }

use GetStorage through an instance or use directly GetStorage().read('key')

final box = GetStorage();

To read values you use read:

print(box.read('quote'));
// out: GetX is the best

In the 2nd Page you can remove the key:

To remove a key, you can use remove:

box.remove('quote');