State StatefulWidget createState

didUpdateWidget() This method is helpful to unsubscribe the old object and subscribe to new one if it is required for the object to be replaced with updated widget configuration. Overriding this method responds when the widget changes (example, to begin implicit animations).

createState method Null safety Creates the mutable state for this widget at a given location in the tree . Subclasses should override this method to return a newly created instance of their associated State subclass: @override State<MyWidget> createState() => _MyWidgetState();

A stateful widget is dynamic: for example, it can change its appearance in response to events triggered by user interactions or when it receives data . Checkbox , Radio , Slider , InkWell , Form , and TextField are examples of stateful widgets.

Flutter commonly uses keys when it needs to uniquely identify specific widgets within a collection . Using keys also helps Flutter preserve the state of StatefulWidget s while they’re being replaced with other widgets or just moved in the widget tree.