The Android framework provides several default views. The base class a view is the View. Views are responsible for measuring, layouting and drawing themselves and their child elements (in case of a ViewGroup). Views are also responsible for saving their UI state and handling touch events. Developers can also create custom views and use them in their application.

It is possible to create custom views by:

Compound views - combining views with a default wiring

Custom views - creating your own views

by extending an existing view, e.g. Button

by extending the View class

The following image shows the default view hierarchy of Android.

View are typically created to provide a user interface experience with is not possible with the default views. Using custom view allows the developer allow to do certain performance optimization, i.e., in case of a custom layout the development can optimize the layout manager for his use case.