Chapter 4Getting to Know the Android User Interface
Chapter 3 discusses activities and their life cycles. An activity is a means by which users interact with the application. However, an activity by itself does not have a presence on the screen. Instead, it has to draw the screen using views and ViewGroups. In this chapter, you find out how to create user interfaces (UIs) in Android and how users interact with the UIs. In addition, you discover how to handle changes in screen orientation on your Android devices.
UNDERSTANDING THE COMPONENTS OF A SCREEN
As explained in Chapter 3, the basic unit of an Android application is an activity, which displays the UI of your application. The activity may contain widgets such as buttons, labels, textboxes, and so on. Typically, you define your UI using an XML file (for example, the activity_main.xml file located in the res/layout folder of your project), which looks similar to what is shown in here.
<?xml version="1.0" encoding="utf-8"?> ...Get Beginning Android Programming with Android Studio, Fourth Edition now with the O’Reilly learning platform.
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