Flutter: possible to detect when a drawer is open?

As https://github.com/flutter/flutter/pull/67249 is already merged and published with Flutter 2.0 here is proper way to detect drawer open/close:

Scaffold(
      onDrawerChanged: (isOpened) {
        //todo what you need for left drawer
      },
      onEndDrawerChanged: (isOpened) {
        //todo what you need for right drawer
      },
)

Best solution

ScaffoldState has a useful method isDrawerOpen which provides the status of open/close.

Example: Here on the back press, it first checks if the drawer is open, if yes then first it will close before exit.

/// create a key for the scaffold in order to access it later.
GlobalKey<ScaffoldState> _scaffoldKey = GlobalKey<ScaffoldState>();

@override
Widget build(context) {
   return WillPopScope(
  child: Scaffold(
    // assign key (important)
    key: _scaffoldKey,
    drawer: SideNavigation(),
  onWillPop: () async {
    // drawer is open then first close it
    if (_scaffoldKey.currentState.isDrawerOpen) {
      Navigator.of(context).pop();
      return false;
    }
    // we can now close the app.
    return true;
  });}

This answer is old now. Please see @dees91's answer.

Detecting & Running Functions When Drawer Is Opened / Closed

• Run initState() when open drawer by any action.
• Run dispose() when close drawer by any action.

class MyDrawer extends StatefulWidget {
    @override
    _MyDrawerState createState() => _MyDrawerState();
}

class _MyDrawerState extends State<MyDrawer> {

    @override
    void initState() {
        super.initState();
        print("open");
    }

    @override
    void dispose() {
        print("close");
        super.dispose();
    }

    @override
    Widget build(BuildContext context) {
        return Drawer(
            child: Column(
                children: <Widget>[
                    Text("test1"),
                    Text("test2"),
                    Text("test3"),
                ],
            ),
        );
    }
}

State Management Considerations

If you are altering state with these functions to rebuild drawer items, you may encounter the error: Unhandled Exception: setState() or markNeedsBuild() called during build.

This can be handled by using the following two functions in initState() source

Option 1

WidgetsBinding.instance.addPostFrameCallback((_){
  // Add Your Code here.
});

Option 2

SchedulerBinding.instance.addPostFrameCallback((_) {
  // add your code here.
});

Full Example of Option 1

@override
void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_) {
        // Your Code Here
    });
}