What is ViewModel in Android SDK?

A ViewModel in the Android SDK is a class that is designed to store and manage UI-related data in a lifecycle-conscious way. This means that the ViewModel is able to preserve data through configuration changes such as screen rotations. By using ViewModel, your UI data can survive these changes without needing to re-fetch data, thereby improving user experience and minimizing unnecessary work.

ViewModels are part of the Android Architecture Components, and they help in separating the UI data from the UI controllers (such as Activities and Fragments). This separation allows for a cleaner architecture and easier testing.

For example, consider a simple ViewModel for a user profile:

class UserProfileViewModel extends ViewModel { private MutableLiveData user; public LiveData getUser() { if (user == null) { user = new MutableLiveData(); loadUser(); } return user; } private void loadUser() { // Load user data from a repository } }

ViewModel Android SDK UI-related data lifecycle-conscious Android Architecture Components Activities Fragments UserProfile

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