eventBus的使用

eventBus的使用步骤:

//在Activity中,注册和反注册

@Override protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

EventBus.getDefault().register(this); //第1步: 注册

}

@Override protected void onDestroy() {

super.onDestroy();

EventBus.getDefault().unregister(this);//反注册

}

//在注册了的Activity中,声明处理事件的方法

//第2步:注册一个在后台线程执行的方法,用于接收事件

@Subscribe(threadMode = ThreadMode.BackgroundThread)

public void onUserEvent(ClassEvent event) {

　//参数必须是ClassEvent类型, 否则不会调用此方法

}

//在任意地方,调用发送事件

EventBus.getDefault().post(new ClassEvent());//第3步: 发送事件

//在任意地方,注册事件类

class ClassEvent{} //定义一个事件, 可以不包含成员变量,和成员方法

新版本的eventBus的使用,接收数据的回调方法变成了这样:

 　 @Subscribe(threadMode = ThreadMode.MainThread) //在ui线程执行
    public void onUserEvent(UserEvent event) {
    }

    @Subscribe(threadMode = ThreadMode.BackgroundThread) //在后台线程执行
    public void onUserEvent(UserEvent event) {
    }

 

    @Subscribe(threadMode = ThreadMode.Async) //强制在后台执行
    public void onUserEvent(UserEvent event) {
    }

    @Subscribe(threadMode = ThreadMode.PostThread) //默认方式, 在发送线程执行
    public void onUserEvent(UserEvent event) {
    }


举个例子,用eventBus代替handler,实现秒表:

public class MainActivity extends AppCompatActivity {
    private TextView mTextView;
    private int time = 0;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        EventBus.getDefault().register(this);
        mTextView = (TextView) findViewById(R.id.tv_showtime);
        mTextView.setText(0 + "");
        getTime();
    }
    private void getTime() {
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    time++;
                    Thread.sleep(1000);
                    EventBus.getDefault().post(new FirstEvent(time + ""));
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }).start();
    }
    @Subscribe(threadMode = ThreadMode.MainThread)
    public void onUseEvent(FirstEvent event) {
        boolean isMainThread = Thread.currentThread() == Looper.getMainLooper().getThread();
        Log.i("xyz", "" + isMainThread);
        mTextView.setText(event.getMsg());
        getTime();
    }
}

 

其中FirsrtEvent就是简单的一个实体类:

public class FirstEvent {

   private String mMsg;
   public FirstEvent(String msg) {
      // TODO Auto-generated constructor stub
      mMsg = msg;
   }
   public String getMsg(){
      return mMsg;
   }
}