How to call a method in another stateful widget

Question

I am building a podcasting type app, so need to call the record, stop, and play functions in many places, I created the methods, but difficulty to call these methods in other places.

main.dart

class MyApp extends StatefulWidget { @override _MyAppState createState() => _MyAppState(); } class _MyAppState extends State<MyApp> { String statusText = ""; bool isComplete = false; void startRecord() //Need to call all of these method in coming stateful widgets void stopRecord() // void pauseRecord()// void resumeRecord()// void play() // @override Widget build(BuildContext context) { return MaterialApp( home: Builder( builder: (context) => Scaffold( drawer: Drawer( elevation: 2.0, child: ListView( children: <Widget>[ ListTile( title: Text('Home'), onTap: () { Navigator.push( context, MaterialPageRoute( builder: (context) { return MyApp(); }, ), ); }, ), //more code is here Expanded( child: GestureDetector( child: IconButton( icon: Icon(Icons.mic), color: Colors.white, iconSize: 40, onPressed: () async { startRecord(); }), ), ), } class MyHomePage extends StatefulWidget { @override _MyHomePageState createState() => _MyHomePageState(); } class _MyHomePageState extends State<MyHomePage> { @override Widget build(BuildContext context) { return MaterialApp( onPressed: () { startRecord() // need to call the method here. } Pressed: () { stopRecord() // need to call the method here. } Pressed: () { play() // need to call the method here. } ), }

Need to call all the methods from a first stateful widget for bottom stateful widgets

also, need to call these methods for other classes when code progress

both stateful widgets are in the main.dart. I could not call the method from the first class for the second stateful widget

Your code has syntax errors. and few questions is your method startRecord outside the _MyAppState Class? and is the classes on different Dart files? And Can you share the whole code? — Adithya Shetty
– Adithya Shetty, Commented Aug 7, 2020 at 12:46
Does this answer your question ? stackoverflow.com/questions/50733840/… — timilehinjegede
– timilehinjegede, Commented Aug 7, 2020 at 13:00
@Derek Checked that but did not understand much, I am a beginner in Flutter — Dinup Kalleril
– Dinup Kalleril, Commented Aug 7, 2020 at 13:15

Alok · Accepted Answer · 2020-08-07 14:08:40Z

This is not a rocket science, just a simple line of code, and you are done.

What you have to do, is to just call the MyHomePage() and let it accept the startRecording() to be used inside the Widget

1. Passing the data from MyApp() to MyHomePage()

 @override Widget build(BuildContext context) { return MaterialApp( // here you pass the your function home: MyHomePage(onPressed: startRecording) ); }

2. Receiving the data in MyHomePage()

class MyHomePage extends StatefulWidget { // let it accept a function type onPressed argument final Function onPressed; // constructor MyHomePage({Key key, this.onPressed}): super(key: key); @override _MyHomePageState createState() => _MyHomePageState(); } class _MyHomePageState extends State<MyHomePage> { @override Widget build(BuildContext context) { return MaterialApp( // simply call the onPressed which received your startRecording() from MyApp onPressed: () => widget.onPressed() }

It should be onPressed: startRecording instead of onPressed: startRecording().
Oh yes, I have mistakenly done that, Thanks for pointing out @Mobina :)
@Alok I already created with home. sharing more code, please check

Benjamin · Accepted Answer · 2020-08-07 13:33:31Z

You can get the state of a parent widget using the BuildContext of the child widget like so:

class MyApp extends StatefulWidget { @override _MyAppState createState() => _MyAppState(); static _MyAppState of(BuildContext context) { return context.findAncestorStateOfType<_MyAppState>(); } } class _MyAppState extends State<MyApp> { String statusText = ""; bool isComplete = false; void startRecord() { print('Hello'); } @override Widget build(BuildContext context) { return MaterialApp( home: MyHomePage(), ); } } class MyHomePage extends StatefulWidget { @override _MyHomePageState createState() => _MyHomePageState(); } class _MyHomePageState extends State<MyHomePage> { @override Widget build(BuildContext context) { MyApp.of(context).startRecord(); return Scaffold( body: Placeholder(), ); } }

Adithya Shetty · Accepted Answer · 2020-08-07 14:03:32Z

Simply define that function outside the class as a stand-alone function like this But if you want to call from inside the class. Heres the code.

inside a different class as a static function:

onPressed: () { _MyAppState().startRecord(); //call using the class name. }

Like this inside your onpressed Statement.

Should work.

Or else what you can do is define the function outside the class. Then use it where ever you want. Like this:

class MyApp extends StatefulWidget { @override _MyAppState createState() => _MyAppState(); } void startRecord(){ . . . } /// Like here outside the class class _MyAppState extends State<MyApp> { String statusText = ""; bool isComplete = false; @override Widget build(BuildContext context) { return MaterialApp(..... } class MyHomePage extends StatefulWidget { @override _MyHomePageState createState() => _MyHomePageState(); } class _MyHomePageState extends State<MyHomePage> { @override Widget build(BuildContext context) { return MaterialApp( onPressed: () { startRecord(); // call Here as follows. }), }

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