EventBus

参考网址:http://greenrobot.org/eventbus/

引入EventBus:
compile 'org.greenrobot:eventbus:3.0.0'

1.快速入门

step1：定义事件
public class MessageEvent {
    public final String message;

    public MessageEvent(String message) {
        this.message = message;
    }
}
step2:接收并处理事件

相应生命周期方法中注册和解注册

@Override
public void onStart() {
    super.onStart();
    EventBus.getDefault().register(this);
}

@Override
public void onStop() {
   EventBus.getDefault().unregister(this);
    super.onStop();
}

 定义处理事件方法

// This method will be called when a MessageEvent is posted (in the UI thread for Toast)
@Subscribe(threadMode = ThreadMode.MAIN)
public void onMessageEvent(MessageEvent event) {
    Toast.makeText(getActivity(), event.message, Toast.LENGTH_SHORT).show();
}
// This method will be called when a SomeOtherEvent is posted
@Subscribe
public void handleSomethingElse(SomeOtherEvent event) {
    doSomethingWith(event);
}

step3:发送事件

EventBus.getDefault().post(new MessageEvent("Hello everyone!"));

2.定义不同线程中处理事件

 

@Subscribe(threadMode = ThreadMode.POSTING) // 和发布者在同一个线程，默认的
public void onMessage(MessageEvent event) {
    log(event.message);
}

// UI线程处理
@Subscribe(threadMode = ThreadMode.MAIN)
public void onMessage(MessageEvent event) {
    textField.setText(event.message);
}

// 后台线程处理
@Subscribe(threadMode = ThreadMode.BACKGROUND)
public void onMessage(MessageEvent event){
    saveToDisk(event.message);
}

// 单独的一个线程 线程池机制
@Subscribe(threadMode = ThreadMode.ASYNC)
public void onMessage(MessageEvent event){
    backend.send(event.message);
}

3.Sticky Events  粘性事件

使用场景：例如想要在Activity初始化前发送事件在Activity启动后执行

发送一个粘性事件：EventBus.getDefault().postSticky(new MessageEvent("Hello everyone!"));

处理接收   

@Override
    public void onStart() {
        super.onStart();
        EventBus.getDefault().register(this);
    }

    @Subscribe(sticky = true, threadMode = ThreadMode.MAIN)
    public void onEvent(MessageEvent event) {
        // UI updates must run on MainThread
        textField.setText(event.message);
    }

    @Override
    public void onStop() {
        EventBus.getDefault().unregister(this);
        super.onStop();
    }

 获取或销毁粘性对象

MessageEvent stickyEvent = EventBus.getDefault().getStickyEvent(MessageEvent.class);
// Better check that an event was actually posted before
if(stickyEvent != null) {
    // "Consume" the sticky event
    EventBus.getDefault().removeStickyEvent(stickyEvent);
    // Now do something with it
}

4.优先级

默认优先级是0 优先级越高先执行  不过不能影响不同线程之间的接收

@Subscribe(priority = 1);
public void onEvent(MessageEvent event) {
…
}

可以在高优先级截断低优先级的处理

@Subscribe
public void onEvent(MessageEvent event){
// Process the event
…

EventBus.getDefault().cancelEventDelivery(event) ;
}

5.混淆

-keepattributes *Annotation*
-keepclassmembers class ** {
    @org.greenrobot.eventbus.Subscribe <methods>;
}
-keep enum org.greenrobot.eventbus.ThreadMode { *; }

# Only required if you use AsyncExecutor
-keepclassmembers class * extends org.greenrobot.eventbus.util.ThrowableFailureEvent {
    <init>(java.lang.Throwable);
}