The Intent can contain a Bundle of supporting information describing the component. With the exception of ContentProvider, each component is activated by an asynchronous message called an Intent. The default behavior can be overridden for a graceful operation, such as saving variables or restoring user interface (UI) elements. Other applications are allowed to use them, too, within the specified permissions.Īs multiple functionalities play out in the OS (some not even related to the intended application, such as an incoming phone call), each component goes through a lifecycle of getting created, focused, defocused, and destroyed. They are instantiated by the Android operating system (OS) as needed. The Four Possible Components of an Android ApplicationĮvery application is made up of one or more of these components.

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. Some examples are editing a note, playing a music file, ringing an alarm, or opening a phone contact. Android Application OverviewĪn Android application consists of various functionalities. Then the focus of this chapter turns to activities and the intents that launch them. 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.

Android Developer's Cookbook, The: Building Applications with the Android SDK: Building Applications with the Android SDKĮach Android application is represented by a single Android project.

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