zane96 / eventbus_annotation

EventBus源码的中文注释

EventBus

###EventBus中文注解。个人对EventBus源码的阅读理解。

• 说明和看法
  • 目前为止对于register, unRegister, post中涉及到的类和重要方法都做了注释，有很深刻的认识。比如post的线程调度，注册函数是如何通过反射找到的等等流程
  • EventBus一般在用的时候我们一般直接getDefault，其实可以通过EventBusBuilder这个类进行链式操作来构造EventBus实例，具体请自己查看源码。很重要的一个变量就是ignoreGeneratedIndex，如果你通过new EventBusBuilder().ignoreGeneratedIndex(true);这个对象来去构造EventBus，那么EventBus不会通过反射去得到注册函数，而是通过编译时期的注解处理器去获得信息。具体代码请查看SubscriberMethodFinder类。
  • 虽然EventBus会默认通过反射获得注册函数，但是获取一次之后会缓存在一个map里面，所以不会每一次都去通过反射去获得注册函数
  • 可以很明显的看到EventBus对于扩展性，框架设计做的一些操作。并且代码简单易懂，不会像系统源码那样一个类就几千行。还是很值得阅读的入门级别的源码。

不论是设计模式，还是ThreadLocal，Executor，反射注解的运用，EventBus都是一个很值得阅读的框架源码。

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EventBus is a publish/subscribe event bus optimized for Android.

EventBus...

• simplifies the communication between components
  • decouples event senders and receivers
  • performs well with Activities, Fragments, and background threads
  • avoids complex and error-prone dependencies and life cycle issues
• makes your code simpler
• is fast
• is tiny (~50k jar)
• is proven in practice by apps with 100,000,000+ installs
• has advanced features like delivery threads, subscriber priorities, etc.

EventBus in 3 steps

1. Define events:
   public class MessageEvent { /* Additional fields if needed */ }
   
   
2. Prepare subscribers
   Register your subscriber (in your onCreate or in a constructor):
   eventBus.register(this);
   
   Declare your subscribing method:
   @Subscribe
public void onEvent(AnyEventType event) {/* Do something */};
   
   
3. Post events:
   eventBus.post(event);

This getting started guide shows these 3 steps in more detail.

Add EventBus to your project

Please ensure that you are using the latest version by checking here

Gradle:

    compile 'org.greenrobot:eventbus:3.0.0'

Maven:

<dependency>
    <groupId>org.greenrobot</groupId>
    <artifactId>eventbus</artifactId>
    <version>3.0.0</version>
</dependency>

Or download EventBus from Maven Central

Homepage, Documentation, Links

For more details on EventBus please check EventBus' website. Here are some direct links you may find useful:

Features

Documentation

Changelog

FAQ

How does EventBus compare to other solutions, like Otto from Square? Check this comparison.

License

Copyright (C) 2012-2016 Markus Junginger, greenrobot (http://greenrobot.org)

EventBus binaries and source code can be used according to the Apache License, Version 2.0.

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