Getting 'data != null': is not true error?
It’s because you haven’t initialized a variable. Let’s have a look at this failing example:
class TestsScreen extends StatefulWidget {
@override
_TestsScreenState createState() => _TestsScreenState();
}
class _TestsScreenState extends State<TestsScreen> {
bool _switchValue;
@override
Widget build(BuildContext context) {
return SafeArea(
child: CupertinoSwitch(
value: _switchValue,
onChanged: (bool value) {
setState(() {
_switchValue = value;
});
},
)
);
}
}
Giving a default value to _switchValue will assign a default state to the button. And that fixes the issue.
class TestsScreen extends StatefulWidget {
@override
_TestsScreenState createState() => _TestsScreenState();
}
class _TestsScreenState extends State<TestsScreen> {
bool _switchValue = false;
@override
Widget build(BuildContext context) {
return SafeArea(
child: CupertinoSwitch(
value: _switchValue,
onChanged: (bool value) {
setState(() {
_switchValue = value;
});
},
)
);
}
}