为什么线程没有停止？

Question

我的服务生成一个新线程,并根据通常推荐的中断()方法java方法停止它.当我停止服务时,我在onDestroy()中停止线程.服务停止,并且到达中断代码.但是,很快就会从Runnable的开头重新开始.

public class DoScan extends Service {
    public volatile Thread runner;

    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public void onCreate() {
        super.onCreate();

        startThread();
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        android.util.Log.v("@@@@@@@@@@@@@@@@@@@@", "DoScan.onDestroy");
        stopThread();
    }


    public synchronized void startThread(){
        if(runner == null){
            android.util.Log.v("@@@@@@@@@@@@@@@@@@@@", "DoScan.startthread");     
            runner = new Thread(new ScanningThread());
            runner.start();
        }
    }
    /* use a handler in a loop cycling through most of oncreate.
     * the scanningthread does the work, then notifies the svc's uithread
     */

    public synchronized void stopThread(){
        if(runner != null){
            android.util.Log.v("@@@@@@@@@@@@@@@@@@@@", "DoScan.stopthread");
            Thread moribund = runner;
            runner = null;
            moribund.interrupt();
            android.util.Log.v("@@@@@@@@@@@@@@@@@@@@", "interrupted?" + moribund.isInterrupted());
        }
    }
        }

Answer 1

我认为最安全的方法是有一个标志,以便线程在其主循环中检查它.

class ScanningThread extends Thread {
    // Must be volatile:
    private volatile boolean stop = false;

    public void run() {
        while (!stop) {
            System.out.println("alive");
        }
        if (stop)
            System.out.println("Detected stop");
    }

    public synchronized void requestStop() {
        stop = true;
    }
}

public synchronized void startThread(){
    if(runner == null){
        android.util.Log.v("@@@@@@@@@@@@@@@@@@@@", "DoScan.startthread");         
        runner = new ScanningThread();
        runner.start();
    }
}

public synchronized void stopThread(){
    if(runner != null){
        android.util.Log.v("@@@@@@@@@@@@@@@@@@@@", "DoScan.stopthread");
        runner.requestStop();
        runner = null;
    }
}

Answer 2

问题是你的线程需要通过定期检查中断并在线程被中断时退出来进行协作.除非你在线程中放置以下内容......

 // Processing...
 if ( Thread.interrupted() ){
    return;
 }
 // More processing...
 try{
    Thread.sleep(sleeptime);
 }catch(InterruptedException interrupt){
    return;
 }
 // Rinse and repeat...

...你的线程会忽略它被中断的事实.Lucas S.提出的方法基本相同,只是如果线程被阻塞,使用中断将生成异常,而在Lucas S.的方法下,您可能必须无限期地等待线程退出.