Each Android application is represented by a single Android project. An overview of the project structure, including a brief introduction to the basic building blocks of an application, is provided as useful background information for the recipes in this book. Then the focus of this chapter turns to activities and the intents that launch them.
An Android application consists of various functionalities. Some examples are editing a note, playing a music file, ringing an alarm, or opening a phone contact. These functionalities can be classified into four different Android components, shown in Table 2.1, each of which is specified by a Java base class.