Creating String by using onPressed function - flutter

Question

I want to make a User's settings screen with a couple of FlatButtons. I want to use onPressed function to create String when the button is pressed and than pass it further to Settings object and save it on disk.
The problem is - I'm new to Dart/Flutter and completely out of ideas here. I have read the docs about Shared Preferences, Streams, Async etc., but I was unable to find an answer to:
How can I create a String by using onPressed?
Can someone tell me how the code would look like or is it even the right approach to solve it this way.
Thanks in advance!

Answer 1

Alright , you can do it in multiple ways.
Here i created an example for you copy/paste run it so you can understand .
import 'package:flutter/material.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
visualDensity: VisualDensity.adaptivePlatformDensity,
),
home: MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
int _counter = 0;
List<String> settings = new List();
void _incrementCounter() {
setState(() {
_counter++;
});
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
(settings.isEmpty) ?Center(child:Text("no settings found")) :
ListView.builder(shrinkWrap: true,itemCount: settings.length,itemBuilder: (context,i)
{
return Center(child: Text("${settings[i]}"));
})
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: ()
{
setState(() {
settings.add('random setting');
});
},
tooltip: 'Increment',
child: Icon(Icons.add),
), // This trailing comma makes auto-formatting nicer for build methods.
);
}
}
explanation :
i created List settings wich has no data at the beginning.
and i check if setting are empty i show empty settings , else it will render the data.
the button with + sign is adding new strings to the list and will rebuild the widget to show it . with setState({});
hope that helps.