Flutter Lifecycle: How to correctly use dispose()? - firebase

Question

I'm new to flutter and currently have a very basic app where I've managed to implement the Application Life cycle Management. If the app has been closed it returns AppLifecycleState.inactive then AppLifecycleState.paused then when I open it up again it returns AppLifecycleState.resume, Which all works fine. My issue is I want the life cycle to only work on one of my pages, when I navigate to a second page I want the life cycle to stop.
How can I use the dispose() on my second page to stop the life cycle?
I was thinking about importing my first file into my second file then calling the dispose(), but would that work?
I know the dispose() is used to end the life cycle which I can trigger if its on the file but I would like to trigger it within another file.
Is what im asking evening possible or am I thinking about this the wrong way?
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(),
);
}
}
class MyHomePage extends StatefulWidget {
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> with WidgetsBindingObserver {
#override
void initState() {
WidgetsBinding.instance.addObserver(this);
super.initState();
}
#override
void dispose() {
WidgetsBinding.instance.removeObserver(this);
super.dispose();
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Flutter Tutorial Lifecycle'),
),
body: Center(),
);
}
}

Answer 1

Try making new separated service for lifecycle like this.
class MyLibrary with WidgetsBindingObserver {
AppLifecycleState? _state;
AppLifecycleState? get state => _state;
MyLibrary() {
WidgetsBinding.instance!.addObserver(this);
}
/// make sure the clients of this library invoke the dispose method
/// so that the observer can be unregistered
void dispose() {
WidgetsBinding.instance!.removeObserver(this);
}
#override
void didChangeAppLifecycleState(AppLifecycleState state) {
this._state = state;
}
void someFunctionality() {
// your library feature
}
}
Now you can dispose life cycle at any page by using
MyLibrary().dispose();