firebase bool passes to null bug - firebase

Question

Hello I am trying to change the data in firebase when I click the button from true to false and from false to true but when I click the value in the database goes to null.
Anyone know what’s wrong? Thank you.
class _MyHomePageState extends State<MyHomePage> {
bool selected;
#override
void initState() {
super.initState();
setInitialValue();
}
setInitialValue() async {
final value = await _incrementCounter();
setState(() {
selected = value?? true;
});
}
_loadCounter(bool value) async {
SharedPreferences prefs = await SharedPreferences.getInstance();
prefs.setBool('select', value);
}
Future<bool> _incrementCounter() async {
SharedPreferences prefs = await SharedPreferences.getInstance();
bool boolValue = prefs.getBool('select');
return boolValue;
}
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(),
body: Center(
child: Column(
children: <Widget>[
Padding(
padding: const EdgeInsets.all(8.0),
child: Center(child: Text('ola'))),
MaterialButton(
color: Theme.of(context).primaryColor,
child: Text( 'Add', style: TextStyle(color: Colors.white), ),
onPressed: () {
Firestore.instance.collection('teste').document('eHJzjbq6c7MwrObrR9XY').updateData({'mover' : selected});
}
),
],
),
),
);
}
}

Answer 1

It seems that the value of the selected variable is not being set correctly, hence when you try to update the document you're sending a null value. Try to verify the value of selected to check if it has indeed a boolean value before writing it to firestore.