第一步：在build.gradle中添加依赖dependencies {

 compile 'org.greenrobot:eventbus:3.0.0'}

第二步：创建一个 Event类： 注意：enum 不是class

public enum  Event {//消息名，可以根据这个名字判断是哪个消息    IMAGE_LOADER_SUCCESS;}

//------------主布局文件------------------------

<TextView    android:layout_width="match_parent"    android:layout_height="wrap_content" android:id="@+id/tv_text" /><Button android:layout_width="match_parent" android:layout_height="40dp" android:text="点击跳转到TwoActivity" android:id="@+id/bt_button"/>

//-----------TwoActivity布局-----------------------

<Button    android:layout_width="match_parent" android:layout_height="wrap_content" android:id="@+id/bt_button2" android:text="发送消息"/>

//---------创建一个消息了---MessageEvent ------------------------

public class MessageEvent {private String message;

public String getMessage() {return message; }

public void setMessage(String message) {this.message = message; }

public MessageEvent(String message) {this.message = message; }

public MessageEvent() { }}

//--------------MainActivity -中我们注册事件，用于接收消息，退出时需要注销-----------------

package eventbusdemo.wode.com.eventbusdemo;

import android.content.Intent;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.util.Log;import android.view.View;import android.widget.Button;import android.widget.TextView;

import org.greenrobot.eventbus.EventBus;import org.greenrobot.eventbus.Subscribe;import org.greenrobot.eventbus.ThreadMode;

public class MainActivity extends AppCompatActivity implements View.OnClickListener{

private Button bt_button;private TextView tv_text;

@Override protected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState); setContentView(R.layout.activity_main);//找到控件 bt_button = (Button) findViewById(R.id.bt_button);tv_text = (TextView) findViewById(R.id.tv_text);//在需要订阅事件的地方注册事件 EventBus.getDefault().register(this);//设置监听 bt_button.setOnClickListener(this);

 }//用于接收传MessageEvent这个类的消息 @Subscribe(threadMode = ThreadMode.MAIN)public void onShowMessageEvent(MessageEvent messageEvent) {tv_text.setText("MainActivity:" + messageEvent.getMessage()); }

//用于接收没有传值的消息 /* @Subscribe public void onEventMainThread(Event event){ switch (event){ case IMAGE_LOADER_SUCCESS: Log.i("MainActivity--","IMAGE_LOADER_SUCCESS"); tv_text.setText("IMAGE_LOADER_SUCCESS"); break; } }*/

 @Override public void onClick(View v) {switch (v.getId()){case R.id.bt_button: Intent intent=new Intent(MainActivity.this,TwoActivity.class); startActivity(intent);break; } }

//(5)取消消息订阅 @Override protected void onDestroy() {super.onDestroy(); EventBus.getDefault().unregister(this); }}

//--------------TwoActivity 中，用于发送消息------------------------

package eventbusdemo.wode.com.eventbusdemo;

import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.View;import android.widget.Button;

import org.greenrobot.eventbus.EventBus;

public class TwoActivity extends AppCompatActivity {

@Override protected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState); setContentView(R.layout.activity_two); Button bt_button2= (Button) findViewById(R.id.bt_button2); bt_button2.setOnClickListener(new View.OnClickListener() {@Override public void onClick(View v) {//(3)产生事件，即发送消息 // EventBus.getDefault().post(Event.IMAGE_LOADER_SUCCESS); //传值 EventBus.getDefault().post(new MessageEvent("哈哈哈哈哈")); } });

 }}