Android EventBus的使用

Android EventBus的使用

1.EventBus 2.x的使用請見:http://blog.csdn.net/harvic880925/article/details/40660137

2.EventBus 3.0的使用

今天在這裏討論原理，只介紹一下使用方法和一些特點，等會在後面附上一些鏈接地址(原理和下載鏈接)，親們可以自己去看。

(1)訂閱和取消訂閱

 @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        EventBus.getDefault().register(this);//訂閱
    }

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

(2)priority的作用

• priority 值越大優先級越高，不設置時最低(比設置了的低)
• 相同的優先級或者都沒設置優先級時誰先訂閱誰先收到消息

package com.example.eventbus;

import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import de.greenrobot.event.Subscribe;
import de.greenrobot.event.ThreadMode;

/**
 * 功能:用於測試不同優先級
 * 特點:
 * (1)priority 值越大優先級越高，不設置時最低(比設置了的低)
 * (2)相同的優先級或者都沒設置優先級時誰先訂閱誰先收到消息
 * */
public class SecondActivity extends BaseActivity {
	private TextView textView;
	private Button jump;
	
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_second);
      
        jump = (Button) findViewById(R.id.jump);
        jump.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                start(ThirdActivity.class);
            }
        });
    }

    @Subscribe(threadMode = ThreadMode.MainThread)
    public void onEvent(MsgEvent event){
    	Log.e("-->", "SecondActivity onEvent：priority = null, sticky = null, msg=" + event.msgData);
    }
    
    
    @Subscribe(threadMode = ThreadMode.MainThread, priority = 101)
    public void onEventLowPriority(MsgEvent event){
        Log.e("-->", "SecondActivity onEventLowPriority：priority = 101, sticky = null, msg=" + event.msgData);
    }
    
    @Subscribe(threadMode = ThreadMode.MainThread, priority = 101)
    public void onEventLowPriority2(MsgEvent event){
        Log.e("-->", "SecondActivity onEventLowPriority2：priority = 101, sticky = null, msg=" + event.msgData);
    }
    
    @Subscribe(threadMode = ThreadMode.MainThread, priority = 102)
    public void onEventMidPriority(MsgEvent event){
    	Log.e("-->", "SecondActivity onEventMidPriority：priority = 102, sticky = null, msg=" + event.msgData);
    }
    
    @Subscribe(threadMode = ThreadMode.MainThread, priority = 102 , sticky = false)
    public void onStickyEventMidPriority(MsgEvent event){
    	Log.e("-->", "SecondActivity onStickyEventMidPriority：priority = 102, sticky = false, msg=" + event.msgData);
    }
}

打印結果:

08-25 16:04:30.755: E/-->(21838): SecondActivity onEventMidPriority：priority = 102, sticky = null, msg=send first msg
08-25 16:04:30.755: E/-->(21838): SecondActivity onStickyEventMidPriority：priority = 102, sticky = false, msg=send first msg
08-25 16:04:30.755: E/-->(21838): SecondActivity onEventLowPriority：priority = 101, sticky = null, msg=send first msg
08-25 16:04:30.755: E/-->(21838): SecondActivity onEventLowPriority2：priority = 101, sticky = null, msg=send first msg
08-25 16:04:30.755: E/-->(21838): SecondActivity onEvent：priority = null, sticky = null, msg=send first msg

(3)Sticky

• 後訂閱時，sticky爲true的處理函數才能才能收到消息
• 後訂閱時，priority優先級貌似無效

package com.example.eventbus;

import de.greenrobot.event.EventBus;
import de.greenrobot.event.Subscribe;
import de.greenrobot.event.ThreadMode;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.ActionMode;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

/**
 * 功能:用於測試事件發送後才訂閱消息,sticky的作用
 * 事件發送方法:EventBus.getDefault().postSticky()
 * 描述:第一次顯示該頁面時不訂閱，等postSticky消息發送後，再回到本頁面時，在OnResume中訂閱消息
 * 特點:
 * (1)後訂閱時，sticky爲true的處理函數才能才能收到消息
 * (2)後訂閱時，priority優先級貌似無效
 * */
public class UnregisterActivity extends Activity{
	private boolean firstResume = true;//是否是第一次Resume
	private TextView textView;
	private Button jump;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        firstResume = true;
        jump = (Button) findViewById(R.id.jump);
        jump.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
               Intent in = new Intent(UnregisterActivity.this, SecondActivity.class);
               startActivity(in);
            }
        });
    }
    
    @Subscribe(threadMode = ThreadMode.MainThread)
    public void onEvent(MsgEvent event) {
        Log.e("-->", "UnregisterActivity onEvent：" + event.msgData);
    }

    @Subscribe(threadMode = ThreadMode.MainThread, sticky = true)
    public void onStickyEvent(MsgEvent event) {
        Log.e("-->", "UnregisterActivity onStickyEvent： priority = null, msg = " + event.msgData);
    }
    
    @Subscribe(threadMode = ThreadMode.MainThread, sticky = true, priority = 1010)
    public void onStickyEvent2(MsgEvent event) {
        Log.e("-->", "UnregisterActivity onStickyEvent2：priority = 1010, msg=" + event.msgData);
    }
    
   @Override
	protected void onResume() {
		// TODO Auto-generated method stub
		super.onResume();
		if(!firstResume){
			EventBus.getDefault().register(this);
		}
		firstResume = false;
	}
   
    @Override
    protected void onPause() {
    	// TODO Auto-generated method stub
    	super.onPause();
    	EventBus.getDefault().unregister(this);
    }
}

消息發送後，返回到該頁面時在OnResume中訂閱消息，只有sticky=true的才能收到消息

這裏附上我的demo下載地址:

EventBus 3.0相關參考鏈接:

http://www.cnblogs.com/whoislcj/p/5595714.html

http://blog.csdn.net/angcyo/article/details/48166849