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。

更多相关文章

随机推荐