<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"  
    xmlns:tools="http://schemas.android.com/tools"  
    android:id="@+id/RelativeLayout1"  
    android:layout_width="match_parent"  
    android:layout_height="match_parent"  
    android:gravity="center"  
    tools:context="com.jay.example.handlerdemo1.MainActivity" >  
    <ImageView  
        android:id="@+id/imgchange"  
        android:layout_width="wrap_content"  
        android:layout_height="wrap_content"  
        android:layout_alignParentLeft="true"  
        android:layout_alignParentTop="true" />  
</RelativeLayout> 

public class MainActivity extends Activity {  
    //定義切換的圖片的數(shù)組id  
    int imgids[] = new int[]{  
        R.drawable.s_1, R.drawable.s_2,R.drawable.s_3,  
        R.drawable.s_4,R.drawable.s_5,R.drawable.s_6,  
        R.drawable.s_7,R.drawable.s_8  
    };  
    int imgstart = 0;  
    final Handler myHandler = new Handler()  
    {  
      @Override  
      //重寫(xiě)handleMessage方法,根據(jù)msg中what的值判斷是否執(zhí)行后續(xù)操作  
      public void handleMessage(Message msg) {  
        if(msg.what == 0x123)  
           {  
            imgchange.setImageResource(imgids[imgstart++ % 8]);  
           }  
        }  
    };  
    @Override  
    protected void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.activity_main);  
        final ImageView imgchange = (ImageView) findViewById(R.id.imgchange);  
        //使用定時(shí)器,每隔200毫秒讓handler發(fā)送一個(gè)空信息  
        new Timer().schedule(new TimerTask() {            
            @Override  
            public void run() {  
                myHandler.sendEmptyMessage(0x123);  
            }  
        }, 0,200);  
    }  
} 

<LinearLayout  
    xmlns:android="http://schemas.android.com/apk/res/android"  
    android:layout_width="match_parent"  
    android:layout_height="match_parent"  
    android:orientation="vertical">  
    <EditText  
        android:id="@+id/etNum"  
        android:inputType="number"  
        android:layout_width="match_parent"  
        android:layout_height="wrap_content"  
        android:hint="請(qǐng)輸入上限"/>  
    <Button  
        android:layout_width="match_parent"  
        android:layout_height="wrap_content"  
        android:onClick="cal"  
        android:text="計(jì)算"/>    
</LinearLayout>  

public class CalPrime extends Activity  
{  
    static final String UPPER_NUM = "upper";  
    EditText etNum;  
    CalThread calThread;  
    // 定義一個(gè)線程類  
    class CalThread extends Thread  
    {  
        public Handler mHandler;  
        public void run()  
        {  
            Looper.prepare();  
            mHandler = new Handler()  
            {  
                // 定義處理消息的方法  
                @Override  
                public void handleMessage(Message msg)  
                {  
                    if(msg.what == 0x123)  
                    {  
                        int upper = msg.getData().getInt(UPPER_NUM);  
                        List<Integer> nums = new ArrayList<Integer>();  
                        // 計(jì)算從2開(kāi)始、到upper的所有質(zhì)數(shù)  
                        outer:  
                        for (int i = 2 ; i <= upper ; i++)  
                        {  
                            // 用i處于從2開(kāi)始、到i的平方根的所有數(shù)  
                            for (int j = 2 ; j <= Math.sqrt(i) ; j++)  
                            {  
                                // 如果可以整除，表明這個(gè)數(shù)不是質(zhì)數(shù)  
                                if(i != 2 && i % j == 0)  
                                {  
                                    continue outer;  
                                }  
                            }  
                            nums.add(i);  
                        }  
                        // 使用Toast顯示統(tǒng)計(jì)出來(lái)的所有質(zhì)數(shù)  
                        Toast.makeText(CalPrime.this , nums.toString()  
                            , Toast.LENGTH_LONG).show();  
                    }  
                }  
            };  
            Looper.loop();  
        }  
    }  
    @Override  
    public void onCreate(Bundle savedInstanceState)  
    {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.main);  
        etNum = (EditText)findViewById(R.id.etNum);  
        calThread = new CalThread();  
        // 啟動(dòng)新線程  
        calThread.start();  
    }  
    // 為按鈕的點(diǎn)擊事件提供事件處理函數(shù)  
    public void cal(View source)  
    {  
        // 創(chuàng)建消息  
        Message msg = new Message();  
        msg.what = 0x123;  
        Bundle bundle = new Bundle();  
        bundle.putInt(UPPER_NUM ,  
            Integer.parseInt(etNum.getText().toString()));  
        msg.setData(bundle);  
        // 向新線程中的Handler發(fā)送消息  
        calThread.mHandler.sendMessage(msg);  
    }  
}