ChangeNotifier is a simple class included in the Flutter SDK which provides change notification to its listeners . In other words, if something is a ChangeNotifier , you can subscribe to its changes. (It is a form of Observable, for those familiar with the term.)
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And, when the change notifier gets updated values, it can call a method called ‘notifyListeners()’, and then any of it’s listeners will respond with an action. Listening to a change notifier is done by registering a callback, which is called when notifyListeners is invoked .
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