EventBus事件总线库

GIthub官方地址：

https://github.com/greenrobot/EventBus

使用步骤

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)；

   Gradle中添加一下代码：

 compile 'org.greenrobot:eventbus:3.0.0'

    

Maven:

    org.greenrobot
    eventbus
    3.0.0

测试如下：

public class EventAActivity extends Activity implements View.OnClickListener {

    private Button mButton;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_event_a);
        mButton = (Button) findViewById(R.id.event_button);
        EventBus.getDefault().register(this);
        mButton.setOnClickListener(this);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        EventBus.getDefault().unregister(this);
    }

    @Subscribe
    public void onEventMainThread(MessageEvent event) {
        Toast.makeText(EventAActivity.this, event.message, Toast.LENGTH_SHORT).show();
    }


    @Override
    public void onClick(View v) {
        if (v.getId() == R.id.event_button) {
            Intent intent = new Intent(this, EventBActivity.class);
            startActivity(intent);

        }
    }
}

另一个Activity

public class EventBActivity extends Activity implements View.OnClickListener {

    private Button mButton;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_event_b);
//        EventBus.getDefault().register(this);
        mButton = (Button) findViewById(R.id.event_b_button);
        mButton.setOnClickListener(this);
    }
    @Override
    protected void onDestroy() {
        super.onDestroy();
//        EventBus.getDefault().unregister(this);
    }

    @Override
    public void onClick(View v) {
        EventBus.getDefault().post(new MessageEvent("Hello everyone!"));
    }
}

   当在BActivity中点击发送按钮的时候，可以把消息传递到AActivity中。