make function await flutter - flutter

Question

I have this variable
dynamic _permission = true;
after clicked on button. I need to display sncakbar if _permission= false thats mean user has no permission to access the page else go to page.
but I faced an issue that _permission always equal true.
even if permission return false from api.
here is the code
Future<void> checkPermesssion() async {
String api_token = await getToken();
final response = await http.post(
Uri.parse(PermissionURL),
headers: {'Accept': 'application/json',
'Authorization': 'Bearer $api_token'
},
);
var permission = jsonDecode(response.body)['permission'];
setState(() {
_permission = permission;
});
}
and here is the button code
child: ElevatedButton(
onPressed: () {
checkPermesssion();
_permission ?
Navigator.of(context).push(
MaterialPageRoute(builder: (context) => page()))
:
ScaffoldMessenger.of(context).showSnackBar(
SnackBar(
content: Text(
'You don\'t have permession to access this page '),
behavior: SnackBarBehavior.floating,
margin: EdgeInsets.all(50),
elevation: 30,
action: SnackBarAction(
label: 'Dismiss',
disabledTextColor: Colors.white,
textColor: Colors.yellow,
onPressed: () {
ScaffoldMessenger.of(context).hideCurrentSnackBar();
},
),
),
);
},
How can I do that please

Answer 1

Try this for button's code :
child: ElevatedButton(
onPressed: () async{
await checkPermesssion();
_permission ?
Navigator.of(context).push(
MaterialPageRoute(builder: (context) => page()))
:
ScaffoldMessenger.of(context).showSnackBar(
SnackBar(
content: Text(
'You don\'t have permession to access this page '),
behavior: SnackBarBehavior.floating,
margin: EdgeInsets.all(50),
elevation: 30,
action: SnackBarAction(
label: 'Dismiss',
disabledTextColor: Colors.white,
textColor: Colors.yellow,
onPressed: () {
ScaffoldMessenger.of(context).hideCurrentSnackBar();
},
),
),
);
},