Android Architecture

Android - Architecture :-Android operating system is a stack of software components

Android Architecture

Android Libraries

This category encompasses those Java-based libraries that are specific to Android development. Examples of libraries in this category include the application framework libraries in addition to those that facilitate user interface building, graphics drawing and database access. A summary of some key core Android libraries available to the Android developer is as follows −

  • android.app − Provides access to the application model and is the cornerstone of all Android applications.

  • android.content − Facilitates content access, publishing and messaging between applications and application components.

  • android.database − Used to access data published by content providers and includes SQLite database management classes.

  • android.opengl − A Java interface to the OpenGL ES 3D graphics rendering API.

  • android.os − Provides applications with access to standard operating system services including messages, system services and inter-process communication.

  • android.text − Used to render and manipulate text on a device display.

  • android.view − The fundamental building blocks of application user interfaces.

  • android.widget − A rich collection of pre-built user interface components such as buttons, labels, list views, layout managers, radio buttons etc.

  • android.webkit − A set of classes intended to allow web-browsing capabilities to be built into applications.

Having covered the Java-based core libraries in the Android runtime, it is now time to turn our attention to the C/C++ based libraries contained in this layer of the Android software stack.

Application Framework

The Application Framework layer provides many higher-level services to applications in the form of Java classes. Application developers are allowed to make use of these services in their applications.

The Android framework includes the following key services −

  • Activity Manager − Controls all aspects of the application lifecycle and activity stack.

  • Content Providers − Allows applications to publish and share data with other applications.

  • Resource Manager − Provides access to non-code embedded resources such as strings, color settings and user interface layouts.

  • Notifications Manager − Allows applications to display alerts and notifications to the user.

  • View System − An extensible set of views used to create application user interfaces.