Android启用线程的方法

多线程编程经常使用：Handler(处理)、Thread（线程）和Runnable这三个类
Android的cpu分配的最小单位是线程
Handler一般是在某个线程里创建的，Handler和Thread是相互绑定，一 一对应的。
Runnable是一个接口，Thread是Runnable的子类，二者都算一个进程。
启动线程方式：
1.继承Thread类，改写run方法实现一个线程

public class MyThread extends Thread {  
 
    //继承Thread类，并改写其run方法        
    private final static String TAG = "My Thread ===> ";      
    public void run(){  
        Log.d(TAG, "run");  
        for(int i = 0; i<100; i++)  
        {  
            Log.e(TAG, Thread.currentThread().getName() + "i =  " + i);  
        }  
    }  
} 
//启动
new MyThread().start();  

2.创建一个Runnable对象

public class MyRunnable implements Runnable{  
    private final static String TAG = "My Runnable ===> ";  
 
    @Override  
    public void run() {  
        // TODO Auto-generated method stub  
        Log.d(TAG, "run");  
        for(int i = 0; i<1000; i++)  
        {  
            Log.e(TAG, Thread.currentThread().getName() + "i =  " + i);  
        }  
    }  
} 
//启动
new Thread(new MyRunnable()).start();

3.通过Handler启动线程

public class MainActivity extends Activity {      
    private final static String TAG = "UOfly Android Thread ==>";  
    private int count = 0;  
    private Handler mHandler = new Handler();  
    private Runnable mRunnable = new Runnable() {  
        public void run() {  
            Log.e(TAG, Thread.currentThread().getName() + " " + count);  
            count++;  
            setTitle("" + count);  
            // 每3秒执行一次  
            mHandler.postDelayed(mRunnable, 3000);  //给自己发送消息，自运行
        }  
    };  
    /** Called when the activity is first created. */  
    @Override  
    public void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.main);  
        // 通过Handler启动线程  
        mHandler.post(mRunnable);  //发送消息，启动线程运行
    }  
 
      @Override      
         protected void onDestroy() {       
             //将线程销毁掉       
             mHandler.removeCallbacks(mRunnable);       
             super.onDestroy();       
         }       
}