I understand that StatefulWidget subclasses are intended to be immutable, and that we tend to store state in a State subclass. (Not talking advanced state management techniques here.)
What then, are the perils of storing our model/state in the StatefulWidget class instead of the State class? Since the State instance has a widget property referring to the StatefulWidget, why not store the state there?
For example:
class Foo extends StatefulWidget {
int count = 0; // state
State createState() => FooState();
}
class FooState extends State<Foo> {
Widget build(BuildContext context) {
return Column(children:[
Text(widget.count.toString()),
FloatingActionButton(
onPressed: doIt
)
]);
}
void doIt() {
setState( () {
widget.count += 1;
});
}
}
Would those concerns still apply when state is an object, passed down to the State instance?
For example:
class Foo extends StatefulWidget {
final counter = Counter(0); // state
State createState() => FooState(counter);
}
class FooState extends State<Foo> {
final counter;
FooState(this.counter);
Widget build(BuildContext context) {
return Column(children:[
Text(counter.stringValue()),
FloatingActionButton(
onPressed: doIt
)
]);
}
void doIt() {
setState( () {
counter.increment();
});
}
}
