zoukankan      html  css  js  c++  java
  • android中handler中 obtainmessge与New message区别

    obtainmessage()是从消息池中拿来一个msg 不需要另开辟空间new

    new需要重新申请,效率低,obtianmessage可以循环利用;

    //use Handler.obtainMessage(),instead of msg = new Message();
    //because if there is already an Message object,that not be used by 
    //any one ,the system will hand use that object,so you don't have to 
    //create and object and allocate memory.
    //it  is also another example of object recycling and reusing in android.
    	Message msg = mHandler.obtainMessage();
    	msg.what = UPDATE_LISTVIEW;
    	msg.obj = current + "/" + total + "songs";
    	//this method is called from worker Thread,so we cannot update UI from here.
    	msg.sendToTarget();


    在看下面代码:

    Message msg = handler.obtainMessage();
                            msg.arg1 = i;
                            msg.sendToTarget(); 
    
    
    Message msg=new Message();
        msg.arg1=i;
        handler.sendMessage(msg);


    第一种写法是message 从handler 类获取,从而可以直接向该handler 对象发送消息,第二种写法是直接调用 handler 的发送消息方法发送消息。

  • 相关阅读:
    Tomcat Connector的三种运行模式
    Tomcat管理页面配置
    URI、URL、URN
    利用libcurl进行post
    安装WIA组件
    wget访问SOAP接口
    haproxy+tomcat集群搭建
    Redis主从复制及状态监测
    VB6之Mandelbrot集
    leetcode Word Search
  • 原文地址:https://www.cnblogs.com/krislight1105/p/3748409.html
Copyright © 2011-2022 走看看