Android之Handler详解（3）

c、将消息队列绑定到子线程上，主线程只管通过Handler往子线程的消息队列中投递消息即可。

package com.dxyh.test;import android.app.Activity;import android.os.Bundle;import android.os.Handler;import android.os.HandlerThread;import android.os.Looper;import android.os.Message;import android.util.Log;public class MainActivity extends Activity {	private final static String TAG = "HandlerTest";		private final static int TASK_BEGIN	= 1;	private final static int TASK_1	= 2;	private final static int TASK_2	= 3;	private final static int TASK_END	= 4;		private MyHandler mHandler = null;	    /** Called when the activity is first created. */    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);        Log.i(TAG, "[M_TID:" + Thread.currentThread().getId() + "]" +        		"This is in main thread.");                HandlerThread myLooperThread = new HandlerThread("my looper thread");        myLooperThread.start();                Looper looper = myLooperThread.getLooper();        mHandler = new MyHandler(looper);                // 启动任务（消息只有标识，立即投递）		mHandler.sendEmptyMessage(TASK_BEGIN);		Log.i(TAG, "[S_ID:" + Thread.currentThread().getId() + "]" +				"Send TASK_START to handler.");				// 开始任务1（在mHandler的消息队列中获取一个Message对象，避免重复构造）		Message msg1 = mHandler.obtainMessage(TASK_1);		msg1.obj = "This is task1";		mHandler.sendMessage(msg1);		Log.i(TAG, "[S_ID:" + Thread.currentThread().getId() + "]" +				"Send TASK_1 to handler.");				// 开启任务2（和上面类似）		Message msg2 = Message.obtain();		msg2.arg1 = 10;		msg2.arg2 = 20;		msg2.what = TASK_2;		mHandler.sendMessage(msg2);		Log.i(TAG, "[S_ID:" + Thread.currentThread().getId() + "]" +				"Send TASK_2 to handler.");				// 结束任务（空消息体，延时2s投递）		mHandler.sendEmptyMessageDelayed(TASK_END, 2000);		Log.i(TAG, "[S_ID:" + Thread.currentThread().getId() + "]" +				"Send TASK_END to handler.");    }        class MyHandler extends Handler {    	public MyHandler(Looper looper) {    		super(looper);    	}    	    	// 现在在每个case之后，你可以做任何耗时的操作了    	@Override    	public void handleMessage(Message msg) {    		switch (msg.what) {    		case TASK_BEGIN:    			Log.i(TAG, "[H_TID:" +    				Thread.currentThread().getId() + "] Get TASK_BEGIN");    			break;    			    		case TASK_1:    			Log.i(TAG, "[H_TID:" +    				Thread.currentThread().getId() + "] Get TASK_1");    			break;    			    		case TASK_2:    			Log.i(TAG, "[H_TID:" +    				Thread.currentThread().getId() + "] Get TASK_2");    			break;    			    		case TASK_END:    			Log.i(TAG, "[H_TID:" +    				Thread.currentThread().getId() + "] Get TASK_END");    			finish();    			break;    		}    		super.handleMessage(msg);    	}    }}

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运行结果：