The two aspects of a user interface are screen layout and event handling. Chapter 4, “User Interface Layout,” discussed how layouts are made up of
View objects, such as text and buttons. This chapter shows how to handle events from a user, such as physical key presses, touch events, and menu navigation. It also shows how to utilize a few advanced user interface (UI) libraries, namely gestures and 3D graphics.
Most user interaction with an Android device is captured by the system and sent to a corresponding callback method. For example, if the physical Back button is pressed, the
onBackPressed() method is called. These events can be handled by extending the class and overriding the ...