Android Framework 基础

Android is a stack of software for mobiles that comprised of operating system, middle wares and various basic applications.  The tools and APIs necessary are being provided by Android SDK to develop various applications on the platform of Android while using the Java language.

Features of Android: Application framework: with the help of AF components can be reused and replaced. Dalvik virtual machine (DVM) is used for devices like mobile.Integrated browser created on the basis of ​​WebKit​​ engine. Optimized graphics, SQLite used to store structure data storage. In Media support we can use multimedia files such video and audio and still images.  The technology such as GSM Telephony is depends on hardware. Same in the case with Bluetooth & Edge & Wi-Fi, they all depend on hardware for their functionality.  And again we can say that Camera, GPS & Compass and accelerometer is also depends on hardware for their respective functions. At last but one of the most important features is RDE: Rich Development Environment inclusive of device emulator and various tools used to debug memory and PP (performance profiling) and Eclipse IDE functions.

Architecture of Android:

Given below is the architecture of Android OS:

1. Home
2. Contact
3. Phone
4. Browser
5. Activity Manager
6. Window Manager
7. Content Provider
8. View System
9. Package Manager
10. Telephony Manager
11. Resource Manager
12. Location Manager
13. Notification  Manager
14. Surface Manager
15. Media Manager
16. SQLite
17. Open GL
18. Free Type
19. WebKit
20. SGL
21. SSL
22. Libc
23. Core Libraries
24. Dalvik Virtual Machine
25. Display Driver
26. Camera Driver
27. Flash Memory Driver
28. Binder Driver
29. Keypad Driver
30. Wi-Fi Driver
31. Audio Driver
32. Power Management.

Android Runtime

Libraries in Android includes set of key libraries which performs various function available in the libraries of Core Java Languages.

Android application manipulates its process with the help of the Dalvik-Virtual-Machine (DVM). To run multiple VMs perfectly Dalvik is written there. Minimum memory is being utilized by the     Dalvik with the help of (.dex). The VM is based on register which runs classes composed by java language and that has been converted into .dex with the help of ‘dx’ tool.

The Dalvik VM depends upon the Linux kernel for backdrop functionalities like threading and memory organization.

Applications of Android

Android is available with a set of applications inclusive of email client, program for SMS and browser and calendar, contacts, etc. Applications are drawn using Java language.

Application Framework of Android