"Xamarin Development Android Series 6" Android Fabric Basics (top)

We are already familiar with what Android is, and in the "Xamarin Development Android Series 4" Android Basics article, the first is to show the Android architecture.

It's about 4 floors.

app--Application Layer

Framework--Public architecture layer

Native Libs + Dalvik VM---System class library + virtual machine

Linux Kernel--linux Kernel

Android is a Linux-based system that can run on smartphone tablet devices. such as Android4.0 is based on the Linux2.6 kernel.

In native Libs, a number of service class libraries are provided, which are basically open source class libraries based on C + + development, and provide a common function encapsulation

The Dalvik virtual machine provides parsing of the Android program, also known as the Java IL code. class file. The parsing process is as follows:

The framework layer provides a service interface to the operation of the device, the SDK, which are Java-based implementations that provide SDK wrapper implementations for other service calls, such as cameras, Wifi, location services, system resources, and so on, for developers of developer apps to invoke.

App layer is the application layer, address Book phone SMS mailbox Web browser and other applications, providing user interface.

So integration, the Android development model is the classic multi-layered model, the APP is the presentation layer Framework provides basic functionality to encapsulate the Native Lib +dalvik virtual machine similar to the. NETFramework CLR.

Finally, the executable instructions are sent to the Linux kernel, and the Linux system contains the lowest-level call management of the hardware, which is similar to the SDK COM + call method of the Windows program.

-----------------------------above is the basic of Android architecture, we actually developed only in the app layer and the framework layer-------------------------------------

Application is developed using the SDK provided by the framework.

We highlight the development of apps.

After the Applicaton is developed, it is installed as a package with the. APK compression pack situation. The compressed package contains the compiled instruction file (. dex), resource file, and a manifest file (Androidmanifest.xml) required by the program

and the required class libraries. The installation package can be installed in the form of a network address, a URL email address, or a memory card.

The most important of the package should belong to which manifest file, the manifest file contains the program's Android minimum version information, portal interface, the software involved, the required permissions information, resource files and so on information.

"Xamarin Development Android Series 6" Android Fabric Basics (top)