CODEWITHSUNDEEP
flutter
mohammad
mohammad

Reputation: 2910

how controllers in flutter can rebuild widget without calling setstate

Some widgets like ListView accept a controller.

but I don't know why for example a controller can update the scroll position by calling controller.animateTo() without calling setState?

it is a little strange to me what exactly a controller is? (I know that a controller can be used to customize the behavior of a widget)

and What's going on inside a controller?

Upvotes: 0

Views: 1482

Answers (1)

Rémi Rousselet
Rémi Rousselet

Reputation: 277517

They don't.

Controllers do not make widgets rebuild. They only provide a way to listen to changes (usually through ChangeNotifier/ValueNotifier)

It is then another widget that uses this listen mechanism to call setState.

One example would be AnimatedBuilder. It's a stateful widget that calls setState when animation emits some notifications

Upvotes: 4

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