Applicationcomponents are the essential building blocks of an android application. Each component has its own importance. Some of the component have some interface through which user can access the application and some of them have no User interface but they play an important role while running of an application as well as during the development.

There are four different types of application components having distinct purpose among themselves and has a distinct life cycle during they created and destroyed.

This is the primary classes which provide the graphical user interface to the user and captured the user interaction through that interface. Activity usually implements a single , focused task that user can do like dial a number or opening of browser etc. Activity is the main class user see when they run the application. Activities are designed to provide a graphical user interface or GUI to the user. It enable user to give and receive information to and from an application. Remaining three components has no graphical user interface. Let’s took an example of Whats-app application in which one application shows the recent chats another activity show the contacts available into the Whats App, another one to read the particular chat. Collectively they provide the great user experience.

services are the long running process which run into the background or to perform task for different process. A service has no user interface .e.g. A service might play music in the background while the user in the different application.

Listens to and responds to the events that happen on device. That events   is the system-wide broadcast announcements to which our broadcast receiver responds. Many broadcast systems originates from the systems for e.g. When Image was captured , battery is low etc.

It manages the shared set of application data. You can store your data in file system , SQLite database , on the web ,on the cloud and you can easily access that data  via your application. Through the content provider other application can query your data or modify if contents provider allows it. Content provider manager is available to manage user contact information's.

Building an Android application

Creating an android Application

Define Resources :

Resources are the non-source code entities many difference resource types such as Layout ,Strings , Images , Menus and Animations. Resources allows app to customized for different devices and users.

Implement Classes :

Package the Application :

System package application components and resource into a .APK file. Developer specify required application information in a specified file name as AndroidManifest.xml.

Android Manifest file includes the all relevant information about the Application such as name , icon  etc and required permission application feature and Minimum and maximum API level.

Install and Run  :