Introducing the MVVM Pattern

In developing the Notepad phone application, you will be using the increasingly popular Model-View-ViewModel (MVVM) pattern. MVVM is a design pattern that provides a clear separation between the UI, the application logic, and the data of an application. The model maintains the data, the view displays the data or provides the UI for user interaction, and the view-model acts as the controller, or brain, which handles the events that affect either the data or the view. Figure 3-3 illustrates the elements of the MVVM pattern and its relationships.

Figure 3-3. The MVVM pattern