Flutter Send Data To Other Screen Without Navigator - flutter

Question

I have question how to pass data between pages/screen in flutter without navigator and only using onChanged and streambuilder.
All I want is whenever user write in textfield on first widget, the second widget automatically refresh with the new data from first widget.
Here's my code for first.dart
import 'package:flutter/material.dart';
import 'second.dart';
class First extends StatefulWidget {
First({Key key}) : super(key: key);
#override
_FirstState createState() => _FirstState();
}
class _FirstState extends State<First> {
final TextEditingController _myTextController =
new TextEditingController(text: "");
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: new AppBar(
title: Text("Passing Data"),
),
body: Column(
children: <Widget>[
Container(
height: 120.0,
child: Column(
children: <Widget>[
TextField(
controller: _myTextController,
onChanged: (String value) {
// refresh second with new data
},
)
]
)
),
Container(
height: 120.0,
child: Second(
myText: _myTextController.text,
),
)
],
),
);
}
}
and here's my second.dart as second widget to receive data from first widget.
import 'dart:async';
import 'package:flutter/material.dart';
import 'api_services.dart';
class Second extends StatefulWidget {
Second({Key key, #required this.myText}) : super(key: key);
final String myText;
#override
_SecondState createState() => _SecondState();
}
class _SecondState extends State<Second> {
StreamController _dataController;
loadPosts() async {
ApiServices.getDetailData(widget.myText).then((res) async {
_dataController.add(res);
return res;
});
}
#override
void initState() {
_dataController = new StreamController();
loadPosts();
super.initState();
print(widget.myText);
}
#override
Widget build(BuildContext context) {
return StreamBuilder(
stream: _dataController.stream,
builder: (BuildContext context, AsyncSnapshot snapshot) {
if (snapshot.hasError) {
return Text(snapshot.error);
}
if (snapshot.hasData) {
return Container();
}
if (snapshot.connectionState == ConnectionState.waiting) {
return Row(
children: <Widget>[
Text("Please Write A Text"),
],
);
} else if (snapshot.connectionState != ConnectionState.active) {
return CircularProgressIndicator();
}
if (!snapshot.hasData &&
snapshot.connectionState == ConnectionState.done) {
return Text('No Data');
} else if(snapshot.hasData && snapshot.connectionState == ConnectionState.done) {
return Text(widget.myText);
}
return null;
});
}
}

Answer 1

You have a couple of options. The two simplest are - passing the text editing controller itself through to the second widget, then listening to it and calling setState to change the text in the second widget.
Example
class Second extends StatefulWidget {
Second({Key key, #required this.textController}) : super(key: key);
final TextEditingController textController;
#override
_SecondState createState() => _SecondState();
}
class _SecondState extends State<Second> {
// made this private
String _myText;
#override
void initState() {
_myText = widget.textController.text
widget.textController.addListener(() {
setState((){_myText = widget.textController.text});
);
});
super.initState();
}
...
// then in your build method, put this in place of return Text(widget.myText);
return Text(_myText);
Option 2 is listening to the controller in your first widget and call setState in there. This will rebuild both the first and second widget though, and I think is not as performant as the first option.
Hope that helps