EventBus3.0使用详解

之前也提到过EventBus的使用方法

不过3.0之后EventBus使用方法有所改变，主要是处理订阅消息用了注解的方式。

还是先声明一下EventBus是发布/订阅事件总线。它可以让我们很轻松的实现在Android各个组件之间传递消息，并且代码的可读性更好，耦合度更低。

比如：用来代替BroadReceiver、Handler更新UI、Fragment之间的数据传递等等...

如何使用EventBus3.0:

(1)首先自定义消息类，可以不继承人格其他类也不需要实现任何接口。如：

 

(2)在需要订阅事件的地方注册事件

(3)发送消息

(4)处理消息

在3.0之前，EventBus还没有使用注解方式。消息处理的方法也只能限定于onEvent、

onEventMainThread、onEventBackgroundThread和onEventAsync，分别代表四种线程模型。

而在3.0之后，消息处理的方法可以随便取名，但是需要添加一个注解@Subscribe，并且要指定线程模型（默认为PostThread）

事件处理函数的访问权限必须为public，否则会报异常。

(5)取消消息订阅

至于消息处理的四种线程模型与之前版本同样，上篇文章有过介绍，就不再赘述。

前文链接http://blog.csdn.net/sleepyzzz1002/article/details/50908205

接下来通过一个小例子来体验下具体用法，例子来自http://blog.csdn.net/lmj623565791/article/details/47143563

将其中的BroadCast用EventBus3.0来代替，直接贴代码：

自定义消息类：

package com.sleepyzzz.itentservicedemo;/** * User: datou_SleepyzzZ([e-mail]) * Date: 2016-05-22 * Time: 20:55 * FIXME */public class MessageEvent {    private String path;    public MessageEvent(String path) {        this.path = path;    }    public String getPath() {        return path;    }    public void setPath(String path) {        this.path = path;    }}

ItentService类：

package com.sleepyzzz.itentservicedemo;import android.app.IntentService;import android.content.Context;import android.content.Intent;import android.util.Log;import org.greenrobot.eventbus.EventBus;/** * User: datou_SleepyzzZ([e-mail]) * Date: 2016-05-22 * Time: 20:07 * FIXME */public class UpLoadImgService extends IntentService{    private static final String ACTION_UPLOAD_IMG = "action.UPLOAD_IMG";    public static final String EXTRA_IMG_PATH = "extra.IMG_PATH";    public UpLoadImgService() {        super("upload");    }    //Create and Send a Work Request to an IntentService    public static void startUpload(Context context, String path)    {        Intent intent = new Intent(context, UpLoadImgService.class);        intent.setAction(ACTION_UPLOAD_IMG);        intent.putExtra(EXTRA_IMG_PATH, path);        context.startService(intent);    }    @Override    protected void onHandleIntent(Intent intent) {        if (intent != null)        {            if (intent.getAction().equals(ACTION_UPLOAD_IMG))            {                final String path = intent.getStringExtra(EXTRA_IMG_PATH);                handleUploadImg(path);            }        }    }    private void handleUploadImg(String path) {        //广播       /* try {            Thread.sleep(3000);            Intent localIntent = new Intent(MainActivity.UPLOAD_RESULT);            localIntent.putExtra(EXTRA_IMG_PATH, path);            LocalBroadcastManager.getInstance(this).sendBroadcast(localIntent);        } catch (InterruptedException e) {            e.printStackTrace();        }*/        try {            Thread.sleep(3000);            EventBus.getDefault().post(new MessageEvent(path));        } catch (InterruptedException e) {            e.printStackTrace();        }    }    @Override    public void onCreate() {        super.onCreate();        Log.e("TAG", "onCreate");    }    @Override    public void onDestroy() {        super.onDestroy();        Log.e("TAG", "onDestroy");    }}

主Activity

package com.sleepyzzz.itentservicedemo;import android.os.Bundle;import android.support.v7.app.AppCompatActivity;import android.widget.Button;import android.widget.LinearLayout;import android.widget.TextView;import org.greenrobot.eventbus.EventBus;import org.greenrobot.eventbus.Subscribe;import org.greenrobot.eventbus.ThreadMode;import butterknife.Bind;import butterknife.ButterKnife;import butterknife.OnClick;public class MainActivity extends AppCompatActivity {    public static final String UPLOAD_RESULT = "result";    @Bind(R.id.id_contanier)    LinearLayout mIdContanier;    @Bind(R.id.btn_add)    Button mBtnAdd;    /*private BroadcastReceiver uploadImgReceiver = new BroadcastReceiver() {        @Override        public void onReceive(Context context, Intent intent) {            if (intent.getAction().equals(UPLOAD_RESULT)) {                String path = intent.getStringExtra(UpLoadImgService.EXTRA_IMG_PATH);                TextView tv = (TextView) mIdContanier.findViewWithTag(path);                tv.setText(path + " upload success ~~~ ");            }        }    };*/    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        ButterKnife.bind(this);        /*IntentFilter intentFilter = new IntentFilter();        intentFilter.addAction(UPLOAD_RESULT);        LocalBroadcastManager.getInstance(this).registerReceiver(uploadImgReceiver, intentFilter);*/        //订阅事件        EventBus.getDefault().register(this);    }    //处理消息，用于更新UI    @Subscribe(threadMode = ThreadMode.MAIN)    public void showUploadResult(MessageEvent event)    {        String path = event.getPath();        TextView tv = (TextView) mIdContanier.findViewWithTag(path);        tv.setText(path + " upload success ~~~ ");    }    int i = 0;    @OnClick(R.id.btn_add)    public void onClick() {        //模拟路径        String path = "/sdcard/imgs/" + (++i) + ".png";        UpLoadImgService.startUpload(this, path);        TextView tv = new TextView(this);        mIdContanier.addView(tv);        tv.setText(path + " is uploading ...");        tv.setTag(path);    }    @Override    protected void onDestroy() {        super.onDestroy();        //LocalBroadcastManager.getInstance(this).unregisterReceiver(uploadImgReceiver);        //取消订阅        EventBus.getDefault().unregister(this);    }}

布局文件：

<?xml version="1.0" encoding="utf-8"?><LinearLayout    android:id="@+id/id_contanier"    xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical">    <Button        android:id="@+id/btn_add"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="AddTask"/></LinearLayout>