与多线程结合使用的消息处理类Handler、Message

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.tiaoshi.MainActivity" >
    
    <TextView
        android:id="@+id/text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="每秒变化的文本" />
    <Button
        android:id= "@+id/btn1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/start" />
    <Button
        android:id="@+id/btn2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/stop" />

</LinearLayout>

package com.example.tiaoshi;

import java.util.Date;

import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends ActionBarActivity implements Runnable {
    private Button startBtn = null; 
    private Button stopBtn = null;
    private Thread thread = null;
    private Handler handler = null;
    private TextView text = null;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        this.text = (TextView) this.findViewById(R.id.text);
        //处理消息
        handler = new Handler(){

            @Override
            public void handleMessage(Message msg) {
                if(msg.what==0x101){
                    text.setText("当前时间为："+new Date());
                }
                super.handleMessage(msg);
            }
            
        };
        this.startBtn = (Button) this.findViewById(R.id.btn1);
        startBtn.setOnClickListener(new OnClickListener(){

            @Override
            public void onClick(View arg0) {
                thread = new Thread(MainActivity.this);
                thread.start();
                text.setText("当前时间为："+new Date());
            }
            
        });
        this.stopBtn = (Button) this.findViewById(R.id.btn2);
        stopBtn.setOnClickListener(new OnClickListener(){

            @Override
            public void onClick(View arg0) {
                if(thread!=null){
                    thread.interrupt();
                    thread = null;
                }
                Log.i("提示", "中断线程");
            }
            
        });
    }

    @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;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    @Override
    public void run() {
        try {
            while(!Thread.currentThread().isInterrupted()){
                Message m = handler.obtainMessage();   //获取一个空的message
                m.what = 0x101;        //设置消息标识
                handler.sendMessage(m);  //发送消息
                Thread.sleep(1000);
            }
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        
    }

    @Override
    protected void onDestroy() {
        if(thread!=null){
            thread.interrupt();
            thread = null;
        }
        super.onDestroy();
    }
}

Handler handler = new Handler(); 

package com.example.tiaoshi;

import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.util.Log;

public class LooperThread extends Thread {
    public Handler handler; //声明一个Handler对象
    @Override
    public void run() {
        super.run();
        Looper.prepare(); //初始化Looper对象
        //实例化一个Handler对象
        handler = new Handler(){

            @Override
            public void handleMessage(Message msg) {
                Log.i("Looper", String.valueOf(msg.what));
            }
            
        };
        //获取一个消息
        Message m = handler.obtainMessage();
        //设置Message的what属性的值
        m.what = 0x11;
        // 发送消息
        handler.sendMessage(m);
        //启动Looper
        Looper.loop();
    }
    
}

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        LooperThread thread = new LooperThread(); //创建一个线程
        thread.start();  //开启线程
    }