Android Binder机制总结.docVIP

Android Binder机制总结 Android组件化思想 Android应用的体系结构是基于分布式组件模型。Android应用中的组件之间是松耦合，具有模块化以及可扩展的特性。这些组件可以同时运行在同一个进程中，也可以在不同的进程中。如你编写的应用程序需要显示一个可以滚动的片列表，如果其它某个应用程序已经开发了具有此功能的组件并对外发布了此组件以使其它应用程序能够使用此组件，因此你可以直接调用这个组件来显示图片，而不需要重新开发一个具有此功能的组件。Inter-process communication的缩写形式，主要用于多进程间通信和数据交互。 a) Pipes(管道): Pipes are unidirectional byte-streams that connect the standard output from one process with the standard input of another process. b) Message Queues(消息队列): maintains a queue of messages to which processes can read to and write from, thereby achieving IPC. c) Shared Memory(共享内存): A common memory location which is accessible by all communicating processes. IPC is achieved by writing to and reading from the shared memory location. d) Semaphores(信号量): A semaphore is a shared variable on which processes can signal and wait thereby achieving IPC. e) Signals(信号): A process can send signals to processes with the same uid and gid or in the same process group. f) Sockets: Sockets are bidirectional communication streams. Two processes can communicate with byte-streams by opening the same socket. Android中进程通信方式 Android中的Binder机制源于OpenBinder，它的创造者是Dianne Kyra Hackborn，但是已经不再维护。后来这哥们加入了Google，又重新设计了Android系统中的Binder。 在Android应用中调用其他应用中的组件涉及到跨进程的通信，需要使用Android平台内置的进程间交互机制Binder。Binder进程通信只支持同一台主机上的进程之间的交互，而不支持跨主机的进程交互。 Binder相关基本概念 Binder (Framework) IPC架构[The overall IPC architecture) Binder Driver 内核驱动实现具体的跨进程通信[The kernel-level driver that fascinates the communication across process boundaries] Binder Protocol 和驱动进行交互的协议[Low-level protocol (ioctl-based) used to communicate with the Binder driver] IBinder Interface 定义了Binder对象需要实现的一些固定的接口[A well-defined behavior (i.e. methods) that Binder Objects must implement] AIDL Andriod定义服务调用接口的语法，功能类同WSDL[Android Interface Definition Language used to describe business operations on an IBinder Interface] Binder (Object) A generic implementation of the IBinder interface Binder Token 32位唯一标识一个Binder对象[An abstract 32-bit integer value that uniquely ident