Android Architecture

There are 4 basic that we must understand in building Android-based applications:
1. Activity, is a graphical display that we see when running an application. applications can have more than one Activity
2. Intent, is a set of values ​​that indicate what to do when there is movement of the screen
3. Service, is a service that works in Backend
4. Content providers, enabling an application to be able to store and receive data from the database.

Here Some featur Android:
1. Application framework components can be replaced and modified re-
2. Dalvik virtual machine optimization for mobile devices
3. Integrated browser based on the open source WebKit engine
4. Optimized 2D graphics supporting a custom graphics library; 3D graphics based on the OpenGL ES 1.0 specification (hardware acceleration optional)
5. SQLite for storage of data structures
6. Media support in general supports audio, video and still image formats (MPEG4, H.264, MP3, AAC, AMR, JPG, PNG, GIF)
7. GSM Telephony (hardware dependent)
8. Bluetooth, EDGE, 3G, and WiFi
9. Camera, GPS, compass, and accelerometer