Question

正在创建一个简单的应用程序。应用程序必须显示对话框，在后台运行计时器。当计时器过去时，应该发出哔声。但是，如果在计时器之前单击对话框，则应取消计时器。我发布了迄今为止我所做的事情，用这段代码，先得到蜂鸣声然后再对话框，怎么说主线程计时器已经完成？

public class main扩展Activity {

static final int DIALOG_ADDPLAYERS = 0;

Thread backgroundThread;
TextView myText;
myCounter counter;
MediaPlayer mp;

Handler handler = new Handler(){

    @Override
    public void handleMessage(Message msg) 
    {
            playAudio();
    }

};

 protected Dialog onCreateDialog(int id)
    {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);

        switch(id)
        {
        case 0:

                builder.setTitle("Restart Game");
                builder.setMessage("Are you sure to restart the game?");
                builder.setPositiveButton("YES", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which)
                    {
                        counter.cancel();
                    }});
                builder.setNegativeButton("NO", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which)
                    {
                        counter.cancel();   
                    }   
                });


            break;


        default:
        }
        return builder.create();    
    }

void playAudio()
{
    mp = MediaPlayer.create(this, R.raw.beep);
    mp.setLooping(false);
    mp.start();
    mp.setOnCompletionListener(new OnCompletionListener(){
        public void onCompletion(MediaPlayer arg0)
        {
            finish();
        }
    });
    mp.setOnCompletionListener(new OnCompletionListener(){
        public void onCompletion(MediaPlayer arg0)
        {
            finish();
        }});

}

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



/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    myText = (TextView)findViewById(R.id.mytext);

    //Toast.makeText(this, "onCreate()", Toast.LENGTH_LONG).show();    
    showDialog(0);
    startMyTimer();
}




protected void startMyTimer() 
{    
    counter = new myCounter((long)10000,(long)1000);
    backgroundThread = new Thread(new Runnable(){

        @Override
        public void run() 
        {       
                try 
                {
                    //Thread.sleep(10000);


                    counter.startTimer();

                } 
                catch (Exception e) {

                    e.printStackTrace();
                }


        }

    });
    backgroundThread.start();
}

}

这是我的MyCounter课程：

package com.androidbook.bgthread;

import android.media.MediaPlayer;
import android.media.MediaPlayer.OnCompletionListener;
import android.os.CountDownTimer;

public class myCounter extends CountDownTimer 
{
    public myCounter(long millisInFuture, long countDownInterval) 
    {
        super(millisInFuture, countDownInterval);
        // TODO Auto-generated constructor stub
    }

    @Override
    public void onFinish() 
    {

    }

    @Override
    public void onTick(long millisUntilFinished) 
    {


    }

    public void startTimer()
    {
        start();
    }   

}

这是正确的方法吗？请帮忙。

Answer 1

使用处理程序：http://developer.android.com/reference/android/os/Handler.html。这使您可以从任何其他线程向主线程发送消息。

有用的参考资料位于http://www.tutorialforandroid.com/2009/01/using-handler-in-android.html

如何回复主线程？

1 个答案: