Android?

Android is a software stack for mobile devices that includes an operating system, middleware and key applications. The Android SDK provides the tools and APIs necessary to begin developing applications on the Android platform using the Java programming language.

Android applications are written in the Java programming language.

Application Components

Four types of application components

• Activities
• Services
• Content providers
• Broadcast receivers

The Manifest File

Before the Android system can start an application component, the system must know that the component exists by reading the application's AndroidManifest.xml file (the "manifest" file). Your application must declare all its components in this file, which must be at the root of the application project directory.

The manifest does a number of things in addition to declaring the application's components, such as:

• Identify any user permissions the application requires, such as Internet access or read-access to the user's contacts.
• Declare the minimum API Level required by the application, based on which APIs the application uses.
• Declare hardware and software features used or required by the application, such as a camera, bluetooth services, or a multitouch screen.
• API libraries the application needs to be linked against (other than the Android framework APIs), such as the Google Maps library..
• And more