The user interface (UI) is the look and feel of an operating system. A good interface puts the user first, making commands and access to apps easy to discover. For the programmer, understanding how the interface works and what impact it has on application design is extremely useful.
Android provides an interface that is easy to maneuver, with a home screen that can show apps or widgets (see Figure 1.5). A Google search bar is also present for easy access to both search and Google Now, the contextual information tool from Figure 1.4.
Because Android allows for significant amounts of customization, ...