Android Framework 基礎

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:
 
Application of Architecture of Android.
Home
Contact
Phone
Browser
Application Framework of the architecture of Android OS.
Activity Manager
Window Manager
Content Provider
View System
Package Manager
Telephony Manager
Resource Manager
Location Manager
Notification  Manager
Libraries of the architecture of Android OS.
Surface Manager
Media Manager
SQLite
Open GL
Free Type
WebKit
SGL
SSL
Libc
Runtime of the architecture of Android OS.
Core Libraries
Dalvik Virtual Machine
Linux Kernel for the architecture of Android OS.
Display Driver
Camera Driver
Flash Memory Driver
Binder Driver
Keypad Driver
Wi-Fi Driver
Audio Driver
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
 
Android Operating System allows users to develop abilities to create potentially rich and efficient application in the platform. Developers have access to utilize various devices and location information and background services and also to set up alarms along with notification to the toolbar and many more.