i would like to create a loader data, at the end the load of the data the screen will automaticly change the screen (with Navigator).
BUT i have some problem.
Unhandled Exception: NoSuchMethodError: The method 'ancestorStateOfType' was called on null.
At the end of the method "getDataOfUser()" the "print(a)" executed fine but when it try to change the screen it crash and i have this error :
E/flutter (32148): [ERROR:flutter/lib/ui/ui_dart_state.cc(148)] Unhandled Exception: NoSuchMethodError: The method 'ancestorStateOfType' was called on null.
E/flutter (32148): Receiver: null
E/flutter (32148): Tried calling: ancestorStateOfType(Instance of 'TypeMatcher<NavigatorState>')
E/flutter (32148): #0 Object.noSuchMethod (dart:core-patch/object_patch.dart:50:5)
E/flutter (32148): #1 Navigator.of (package:flutter/src/widgets/navigator.dart:1446:19)
E/flutter (32148): #2 LoginScreenPresenter.initState.<anonymous closure> (package:test_app/login_presenter.dart:35:17)
class loginPresenter extends StatefulWidget {
Vendeur v;
loginPresenter({Key key, this.v}) : super(key: key);
@override
LoginScreenPresenter createState() => new LoginScreenPresenter();
}
class LoginScreenPresenter extends State<loginPresenter> {
RestDatasource api = new RestDatasource();
BuildContext context;
bool finish = false;
@override
void initState() {
getDataOfUser(widget.v).then((a) {
print(a)
Navigator.of(context).pushReplacement(new MaterialPageRoute(
builder: (BuildContext context) => HomePage(
v: widget.v,
)));
});
super.initState();
}
Future<bool> getDataOfUser(Vendeur user) async {
await api.getRegionsFromUser(user.idV).then((list) async {
if (list != null) {
for (var i = 0; i < list.length; ++i) {
await DBProvider.db.newRegion(list[i], 1);
}
}
});
await api.getClientsFromUser(user.idV).then((list) async {
if (list != null) {
for (var i = 0; i < list.length; ++i) {
await DBProvider.db.newClient(list[i], 1);
}
}
});
await api.getInterlocuteursFromUser(user.idV).then((list) async {
if (list != null) {
for (var i = 0; i < list.length; ++i) {
await DBProvider.db.newInterlocuteurs(list[i], 1);
}
}
});
await api.getVisitesFromUser(user.idV).then((list) async {
if (list != null) {
for (var i = 0; i < list.length; ++i) {
await DBProvider.db.newVisite(list[i], 1);
}
}
});
await api.getAvoirsFromUser(user.idV).then((list) async {
if (list != null) {
for (var i = 0; i < list.length; ++i) {
if (list[i].deleted == 0) {
await DBProvider.db.newAvoir(list[i], 1);
}
}
}
});
await api.getRapportsFromUser(user.idV).then((list) async {
if (list != null) {
for (var i = 0; i < list.length; ++i) {
await DBProvider.db.newRapport(list[i], user);
}
}
});
return true;
}
@override
Widget build(context) {
return RaisedButton(
onPressed: () {
Navigator.push(
context,
SlideRightRoute(
widget: HomePage(
v: widget.v,
)));
},
child: Text('go'),
);
}
}
Your context
was never assigned. You are calling Navigator using that context while it is still null. Try to assign it with the context from the page when it is built.
@override
Widget build(context) {
setState(() => this.context = context);
...
}