Android Architecture

5 Layered Architecture :

1. Linux Kernel
2. Libraries
3. Application Framework
4. Application
5. Android Runtime

Linux Kernel

• main work of kernel is to get work from hardware.
• e.g. :
• Display Driver
• Camera Driver : turn on camera, turn off, take picture
• Audio Driver
• Wifi Driver : wifi on/off

Kernel has main 3 parts :

• Device Driver : get work through a particular device(Memory chip, Camera like that)
• Memory Management : Manage the entire memory(which files place where)
• Process Management : playing movies, musics, turn on Blue-tooth

Libraries

• It is some logical groups and some logical instructions that we want to give to kernel to perform and actions.
• e.g. :
• SQLite Libraries
• OpenGL
• Surface Manager

we can see some libraries :

• C/C++ Libraries
• Interface through Java
• Surface Manager
• 2D and 3D graphics
• Media Codes

Application Framework

• It is a set of services that collectively form the environment in which Android applications run and are managed.
• It can be use as reusable, interchangeable and replaceable components of Application.
• Developer make things easier and understandable.
• They can do things without going deep layers, like getting call.
• e.g. :
• Telephone Manager :- It can use for getting calls, making SMS.
• Activity Manager
• Notification Manager

Two parts :

• API Interface :- Manage Entire Application in a single way.
• Activity Manager :- Manages Application life cycle.

Application

• application are build-in our phone Applications.
• It available phone itself are known as Applications.
• e.g. :
• Phone
• Contact
• Browser

Android Run-Time

DVM — Dalvik VM (like JVM — .jar)

• Dex file (.dex)
• Compact and efficient than class file
• Limited Memory and battery power

Core Library

• Collection of I/O etc.
• Java 5 Std edition