线程基础篇Looper

private Handler mHandler_2;

/**
* 寒天星之线程基础篇
*/
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//实例化线程，在handler中规定什么情况触发什么
MyThread_2 thread_2 = new MyThread_2();
thread_2.start();

//这里的newMsg就像一个发消息的入口将情况发给handler让handler进行处理

Message newMsg = Message.obtain();
newMsg.what = 1;
mHandler_2.sendMessage(newMsg);
}
public class MyThread_2 extends Thread {

@Override
public void run() {
Looper.prepare();

mHandler_2 = new Handler() {
public void handleMessage(Message msg) {
switch (msg.what) {
case 1:
Toast.makeText(MainActivity.this, "出来了", 1).show();
break;
case 2:

break;

default:
break;
}
}
};

Looper.loop();
}
}