Enpatika

FocusNode basically focuses on the keyboard event. Let’s suppose you want to control the TextFormField widget as soon as the user taps on it, then you use FocusNode . So, FocusNode class is basically an object that can be used to obtain keyboard focus and to handle keyboard events .

onSaved. An optional method to call with the final value when the form is saved via FormState .

In flutter, controllers are a means to give control to the parent widget over its child state . The main selling point of controllers is that they remove the need of a GlobalKey to access the widget State. This, in turn, makes it harder to do anti-pattern stuff and increase performances.