Android EventBus發布/訂閱事件總線

做過Android開發都會陸續用到這個開源庫EventBus。EventBus是一款針對Android優化的發布/訂閱事件總線。主要功能是替代Intent,Handler,BroadCast在Fragment，Activity，Service，線程之間傳遞消息.優點是開銷小，代碼更優雅。以及將發送者和接收者解耦。下面說說簡單用法。

本文項目資源下載:

一、先定義一個消息實體類MainSendEvent

package com.example.eventbusdemo;

/**
 * 事件消息實體類
 * @author mmxs
 *
 */
public class MainSendEvent {
	protected String mstrMsg;
	
	public MainSendEvent(String msg) {
	    mstrMsg = msg;
	}

	public String getStringMsgData(){
		return mstrMsg;
	}
}

package com.example.eventbusdemo;

import de.greenrobot.event.EventBus;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import android.app.Activity;
import android.content.Intent;

public class MainActivity extends Activity implements OnClickListener{

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		//事件注冊
		EventBus.getDefault().register(this);
		InitUI();
	}

	private void InitUI() {
		Button button = (Button)findViewById(R.id.button1);
		button.setOnClickListener(this);
	}

	@Override
	public void onClick(View v) {
		switch (v.getId()) {
		case R.id.button1:
			Intent intent = new Intent();
			intent.setClass(MainActivity.this, TwoActivity.class);
			startActivity(intent);
			break;

		default:
			break;
		}
		
	}
	
	//事件接受
	public void onEventMainThread(MainSendEvent event){
		if(event != null){
			Toast.makeText(getApplicationContext(),
					MainActivity接受數據 + event.getStringMsgData(),
					Toast.LENGTH_LONG).show();	
			TextView textView = (TextView)findViewById(R.id.textView1);
			textView.setText(event.getStringMsgData());
		}
	}
	
	@Override
	public void onDestroy() {
		//取消注冊
		EventBus.getDefault().unregister(this);
		super.onDestroy();
	}	
}

package com.example.eventbusdemo;

import de.greenrobot.event.EventBus;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
/**
 * 第二個TwoActivity發送事件
 * @author mmsx
 *
 */
public class TwoActivity extends Activity implements OnClickListener{
	
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_two);

		Button button = (Button)findViewById(R.id.button1);
		button.setOnClickListener(this);
		
	}

	@Override
	public void onClick(View v) {
		switch (v.getId()) {
		case R.id.button1:
			//事件發送
			EventBus.getDefault().post(new MainSendEvent(from TwoActivity msg));
			break;
		default:
			break;
		}
		
	}
	



}

1、activity_main

五、效果圖

六、簡單來說的流程

1、事件注冊或者訂閱

EventBus.getDefault().register(this);

public void onEventMainThread(MainSendEvent event){
		if(event != null){
			Toast.makeText(getApplicationContext(),
					MainActivity接受數據 + event.getStringMsgData(),
					Toast.LENGTH_LONG).show();	
			TextView textView = (TextView)findViewById(R.id.textView1);
			textView.setText(event.getStringMsgData());
		}
	}

EventBus.getDefault().unregister(this);

4、事件的發送者

EventBus.getDefault().post(new MainSendEvent(from TwoActivity msg));