QThread发出finished()信号,但isRunning()返回true,isFinished()返回false

Question

下面是我的qthread实现的代码.我试图从卫星获取gps数据.即使程序退出gpsSearch()插槽功能,QThread也不会产生finished()信号.locateMe()只要单击一个按钮,就会调用该函数.第一次没有启动线程并单击该按钮时,它会为isRunning()函数打印true值并为函数打印false值isFinished().我不得不调用quit()QTherad 的函数来手动停止线程.之后,它将转到类中的连接threadQuit()函数gnssProvider.但即便如此,如果我单击按钮,它会在函数中输出true isRunning和false .isFinished()locateMe()

GPSInfo::GPSInfo()
{
    hybridGPSFound = satelliteGPSFound = networkGPSFound = false;
    qDebug()<<"Thread Creating";
    gnssThread = new QThread;
    gnssProvider = new LocationFetcher(this,GEOLOCATION_PROVIDER_GNSS,1);
    gnssProvider->moveToThread(gnssThread);
    connect(gnssThread, SIGNAL(started()), gnssProvider, SLOT(gpsSearch()));
    connect(gnssThread, SIGNAL(finished()), gnssProvider, SLOT(threadQuit()));
}
void LocationFetcher::gpsSearch()
{
    if (BPS_SUCCESS != geolocation_request_events(0))
    {
       fprintf(stderr, "Error requesting geolocation events: %s", strerror(errno));
       return;
    }
    geolocation_set_provider(GPS_Search_Provider);
    geolocation_set_period(GPS_Search_Period);
    while (!stopThread)
    {
        bps_event_t *event = NULL;
        bps_get_event(&event, -1);

        if (event)
        {
            if (bps_event_get_domain(event) == geolocation_get_domain() && bps_event_get_code(event) == GEOLOCATION_INFO)
            {
                handle_geolocation_response(event);
                break;
            }
        }
    }
    geolocation_stop_events(0);

    this->quit();

}
void GPSInfo::LocateMe()
{
    qDebug()<<"Thread Running: "<<gnssThread->isFinished();
    qDebug()<<"Thread Running: "<<gnssThread->isRunning();

    gnssThread->start();
    hybridThread->start();
    networkThread->start();

 }

Answer 1

QThread生命周期的工作方式如下:

1. 你打电话QThread::start().
2. 此时,isRunning()应该开始返回true.
3. 线程内部开始.它们发出started()信号.
4. 线程内部调用run().
5. 除非你在子类中重写它,否则run()调用exec().
6. exec()进入一个事件循环并停留在那里直到quit()或被exit()调用.
7. exec()然后run()回到内部.
8. 此时,isFinished()应该开始返回true和isRunning()false.
9. 内部发出finished()信号.
10. 内部做了一些最后的清理工作.
11. 线程终止为真实.

所以你需要quit()在你的位置提取器完成后调用- 但是this->quit()没有调用quit()线程!这可能就是它没有做任何事情的原因.

您的代码看起来有点像本文后的图案:

http://mayaposch.wordpress.com/2011/11/01/how-to-really-truly-use-qthreads-the-full-explanation/

注意她如何给她的工人一个finished()信号(不一样QThread::finished)并将其连接到QThread::quit()插槽.