How can I get it to work?
@override
void dispose() {
timer.cancel();
super.dispose();
}
And this is what I have:
class _ListCell extends State<ListCell> {
@override
void initState() {
super.initState();
Timer timer = Timer.periodic(Duration(seconds: 1), (_) => ListCell());
}
Constantly getting the error:
Error: The getter 'timer' isn't defined for the class '_ListCell'.
You're getting the error because the timer variable is defined out of the scope of the dispose method. This is because you defined the variable in the initState method.
Solution:
Move the definition of the timer variable outside the initState method like this:
class _ListCell extends State<ListCell> {
Timer? timer;
@override
void initState() {
super.initState();
timer = Timer.periodic(Duration(seconds: 1), (_) => ListCell());
}
...
Since the timer variable is now nullable as it is of type Timer?, you need to use the null-check operator on it in the dispose method.
@override
void dispose() {
timer?.cancel();
super.dispose();
}
Checkout Dart's Lexical Scope
Timer? timer;. I have edited my answer.timer?.cancel. The difference is that timer?.cancel() means that the cancel() method will only run if timer is not null while timer!.cancel() means the cancel() method will run regardless so this is to be used when you're absolutely sure the variable is not null.