ValueNotifier Explained | Flutter for Android Developers

What’s ValueNotifier?

The ValueNotifier class is a specialized ChangeNotifier that holds a single value. It notifies its listeners when the value is replaced with a new value that is not equal to the old value, as determined by the equality operator. Key properties include ‘value’, which represents the current value, and methods like ‘addListener’ and ‘notifyListeners’.

Check the official documentation for more.

ValueNotifier explained for Android Developers

For Android developers, the ValueNotifier can be compared to LiveData in Android’s architecture components. Just like LiveData, ValueNotifier allows you to observe changes to a single piece of data. However, while LiveData can handle mutable data types, ValueNotifier is best suited for immutable data types, as it only notifies listeners when the reference to the value changes, not when the contents of a mutable object change.

Example Code

Here is an example of how to use ValueNotifier:

ValueNotifier<int> counter = ValueNotifier<int>(0);

void incrementCounter() {
  counter.value++;
  counter.notifyListeners();
}

counter.addListener(() {
  print('Counter value: ${counter.value}');
});

ValueNotifier Remarks

In conclusion, the ValueNotifier class is a powerful tool for managing state in Flutter applications. Its simplicity and efficiency make it a great choice for scenarios where you need to observe changes to a single value, especially when working with immutable data.