主线程有默认的消息队列。子线程需要创建自己的消息队列。有了消息队列才可以发消息，处理消息。
public class MainActivity extends Activity {
private Button btn=null;
private TextView tv=null;
private MyHandler myHandler=null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//获得和当前线程关联的Looper实例
Looper looper=Looper.myLooper();
myHandler= new MyHandler(looper);
btn=(Button)this.findViewById(R.id.button1);
tv=(TextView)this.findViewById(R.id.textView1);
btn.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View arg0) {
//启动线程
(new MyThread()).start();
}
});
}
public class MyThread extends Thread{
@Override
public void run() {
Message msg=Message.obtain();
msg.arg1=100;
msg.arg2=200;
msg.obj="android and java";
myHandler.sendMessage(msg);
super.run();
}
}
//定义一个Handler子类处理子线程
public class MyHandler extends Handler{
public MyHandler(){
}
//looper管理与之匹配的线程
public MyHandler(Looper looper)
{
super(looper);
}
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
Log.i("<<<arg1<<<", msg.arg1+"");
Log.i("<<<arg2<<<", msg.arg2+"");
Log.i("<<<obj<<<", msg.obj+"");
tv.setText( msg.obj+"");
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
子线程接收消息并处理数据
Handler来管理消息队列，Looper来管理Handler，使得其能够运行起来
public class MainActivity extends Activity {
private Button btn=null;
private TextView tv=null;
private Handler handler=null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//启动线程
(new MyThread()).start();
btn=(Button)this.findViewById(R.id.button1);
tv=(TextView)this.findViewById(R.id.textView1);
btn.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View arg0) {
//主线程发消息
Message msg=Message.obtain();
msg.arg1=100;
msg.arg2=200;
msg.obj="android and java";
handler.sendMessage(msg);
}
});
}
//子线程来处理消息
public class MyThread extends Thread{
@Override
public void run() {
//Initialize the current thread as a looper. This gives you a chance to create handlers that then reference
Looper.prepare();//循环消息队列
//接收并处理数据
handler=new Handler(){
@Override
public void handleMessage(Message msg) {
Log.i("<<<<<arg1<<<", msg.arg1+"");
Log.i("<<<<<arg2<<<", msg.arg2+"");
Log.i("<<<<<obj<<<", msg.obj+"");
//tv.setText(msg.obj+"");
super.handleMessage(msg);
}
};
//Run the message queue in this thread
Looper.loop();//直到消息队列循环结束
super.run();
}
}
}