How to use DrawerControllerState in a Drawer? - flutter

Question

Minimal code:
void main() => runApp(MaterialApp(home: MainPage()));
class MainPage extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(),
drawer: MyDrawer(),
);
}
}
class MyDrawer extends StatelessWidget {
final _drawerKey = GlobalKey<DrawerControllerState>();
#override
Widget build(BuildContext context) {
return Drawer(
key: _drawerKey,
child: RaisedButton(
onPressed: () => print(_drawerKey.currentState), // Prints null
child: Text('Show Dialog'),
),
);
}
}
When I press the button, it prints null, so what's the correct way of using the DrawerControllerState?

Answer 1

See, the problem is, you are not using your key correctly. Firstly, in order to get the state of the Drawer, you need to have ScaffoldState not the DrawerControllerState type key.
With the use of ScaffoldState.currentState, you will be getting the data. Also, if you want to see whether your drawer is open or closed. You can use it like this:
ScaffoldState.currentState.isDrawerOpen
There are two ways to do this:
1. Declaring the GlobalKey gloabally for accessing it anywhere
void main() => runApp(MaterialApp(home: MainPage()));
// declare it globally or make your drawer inside the MainPage only
final GlobalKey<ScaffoldState> _scaffoldKey = GlobalKey<ScaffoldState>();
class MainPage extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Scaffold(
key: _scaffoldKey, // <-- Use your key here not for drawer
appBar: AppBar(),
drawer: MyDrawer(),
);
}
}
class MyDrawer extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Drawer(
child: RaisedButton(
onPressed: () => print(_scaffoldKey.currentState.isDrawerOpen), // <-- prints true, when open
child: Text('Show Dialog'),
)
);
}
}
2. Make your drawer inside your MainPage only. Easily accessible
class MainPage extends StatelessWidget {
final GlobalKey<ScaffoldState> _scaffoldKey = GlobalKey<ScaffoldState>();
Drawer get _drawer => Drawer(
child: RaisedButton(
onPressed: () => print(_scaffoldKey.currentState.isDrawerOpen), // <-- prints true when opened
child: Text('Show Dialog'),
)
);
#override
Widget build(BuildContext context) {
return Scaffold(
key: _scaffoldKey, // <-- Using Key for Scaffold
appBar: AppBar(),
drawer: _drawer
);
}
}
Passing the GlobalKey from MainPage to MyDrawer won't help. You can play with that.