Android之Handler详解（三）

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);
    	}
    }
}

 

运行结果：