How to call method in state class in flutter? - flutter

Question

I want to call the method from HomeState class to _MyHomePageState class.But i have no idea to do that.
this is main.dart :
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,
),
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> {
#override
Widget build(BuildContext context) {
Home home = new Home();
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: (){}
),
);
}
}
Home class:
class Home extends StatefulWidget {
#override
State<StatefulWidget> createState() {
return HomeState();
}
}
class HomeState extends State<Home> {
int numberPrint(){
setState((){});
}
#override
Widget build(BuildContext context) {
}
}
I want to call the method numberPrint() in floatingbutton in _MyHomePageState class in main.dart.
Please help me to do that.

Answer 1

Please take a look at how I would have handled, this is not the best, but it would give you a better idea.
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,
),
home: MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
//MyHomePage---------------------------------------------------
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
MyController controller = MyController();
#override
Widget build(BuildContext context) {
Home home = new Home(controller:controller);
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: controller.execute,
),
);
}
}
//Home---------------------------------------------------------------------
class Home extends StatefulWidget {
Home({this.controller});
final MyController controller;
#override
State<StatefulWidget> createState() {
return HomeState();
}
}
class HomeState extends State<Home> {
initState(){
widget.controller.addListener(numberPrint);
}
numberPrint(){
setState((){});
}
#override
Widget build(BuildContext context) {
}
}
//MyController--------------------------------------------------------
class MyController{
Function listener;
addListener(Function fn){
listener = fn;
}
execute(){
listener();
}
}

Answer 2

In general, I use some kind of page nerve center through which widgets can register their setState functions or other things such as FocusNode and even data.
For example,
class PageNerveCenter{
Function requireHomeRebuild;
}
PageNerveCenter _pageNerveCenter = PageNerveCenter();
class Home extends StatefulWidget{...}
class _HomeState extends State<Home>{
...
#override
initState(){
super.initState();
// register setState
_pageNerveCenter.requireHomeRebuild = (){
setState((){})
};
}
#override
dispose(){
// remove setState when object is disposed
_pageNerveCenter.requireHomeRebuild = (){};
}
...
}
In some other widget (same file/library),
_pageNerveCenter.requireHomeRebuild();
This approach then allows you to call a widget's setState from anywhere in the file, from inside another widget.
In my own experience, this approach has helped to easily break down my widget tree and only rebuild those widgets that actually need to rebuilt too.
I would certainly like to hear other more experienced flutter developers about their take on this approach since I am relatively new too.