Android applications

To build an Android application, a programmer is required have been familiar with the Java programming language. Then use the Software Development Kit ( SDK ) provided by Android. This SDK opens the way for programmers to access Application Programming Interface ( API ) Android.
SDK is installed on this PC includes several tools, including sample applications and the Android emulator. Android emulator is a program that duplicates the functions of a smartphone that runs on the Android platform. Emulator also serves as a means of testing applications on the PC, before it is embedded in the Android smartphone.

Figure. One of the applications on Android for weather forecasts

Google describes Android applications into the four basic building blocks ( not all applications have the fourth ), namely:
1. Activities
That is when an application screen display on the screen. For example, a GPS application has a basic map screen, screen travel plans, and screen routes on it. The third appearance of this screen are called activities.
2. intents
Ie the displacement mechanism of an activity to another activity. For example, when planning a trip to the GPS applications, intent to interpret the input and the screen route on the map screen.
3. Services
That is similar to the service on PCs and servers, programs that run behind the scenes, without interference from the user.
4. Content Provider
That is the mechanism that allows an application to share information with other applications.