Problem Statement
What is ChangeNotifier and how does it work?
Explanation
ChangeNotifier is a class from Flutter's foundation library that implements the observable pattern, maintaining a list of listeners and notifying them when notifyListeners() is called. You extend ChangeNotifier in your model classes, call notifyListeners() after changing state, and listeners (usually UI widgets) automatically rebuild to reflect the changes.
ChangeNotifier is commonly used with Provider through ChangeNotifierProvider, which handles subscribing to notifications and rebuilding widgets efficiently. When you change a property in your ChangeNotifier subclass, you call notifyListeners() to notify all listening widgets, which then call build() to update the UI with new data.
ChangeNotifier is simple and effective for mutable state management, following a pattern familiar to developers from other frameworks. However, you must remember to call notifyListeners() after state changes, and you should dispose ChangeNotifier instances properly to avoid memory leaks. Provider handles disposal automatically when using ChangeNotifierProvider.
