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.
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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();
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