Qt 信号发出但插槽从未调用

Question

我想使用插槽和信号连接两个 object（播放器和 DownloadWebm），但发生了一些奇怪的事情。这是我的代码：

  LogInWindow *log_in=new LogInWindow(cstr,centerX,centerY,start_byte,end_byte);
    QWidget::connect(log_in,SIGNAL(editingFinished()),&loop,SLOT(quit()));

    loop.exec();//stop executing bellow code till user input a movie id

    DownloadWebm *download_webm=nullptr;//download_webm is initialized in myThread constructor

    MyThread *DownloadWebm_Thread = new  MyThread(download_webm,cstr,start_byte,end_byte);

    DownloadWebm_Thread->start();//start the thread

    LinuxWebmPlayer *player = new LinuxWebmPlayer("video.webm",0);


    while(download_webm == nullptr){}//wait till download_webm is initialized

    qRegisterMetaType<Video_Bytes_Package>("Video_Bytes_Package");
    qRegisterMetaType<Info>("Info");

    QObject::connect(download_webm,SIGNAL(send_video_info(Info)),player,SLOT(set_video_info(Info)));
    QObject::connect(download_webm,SIGNAL(send_packege(Video_Bytes_Package)),player,SLOT(add_packeges(Video_Bytes_Package)));
    QObject::connect(download_webm,SIGNAL(send_finish_downloading(bool)),player,SLOT(video_is_commplet()));
    QObject::connect(download_webm,SIGNAL(send_one_cluster_recived()),player,SLOT(calculate_frames()));

  const bool connected =  QObject::connect(player,SIGNAL(yes()),download_webm,SLOT(slot()));
  emit player->yes();
  qDebug() << "Connection established?" << connected;//return true
  Q_ASSERT(connected);

当我将 download_webm 连接到播放器时，插槽会接收到 download_webm 发出的信号但是当我尝试将播放器连接到 download_webm 时，连接成功，发出信号但从未调用来自 download_webm 的插槽。

DownloadWebm 运行在另一个线程中。

这是我在 downloadwebm 中的信号声明：

 class DownloadWebm : public QObject
{

    Q_OBJECT

public:
    DownloadWebm();
    DownloadWebm(char *link,const char *app_path,long x,long y);
    void start();
public slots:
    void slot();
    void first_package_analyzed(int,long);

 private:
  ................
  ................ 

  signals:
   void send_packege(Video_Bytes_Package package);
   void send_video_info(Info info);
   void send_finish_downloading(bool) ;

和玩家 header :

   class LinuxWebmPlayer : public QMainWindow
{
    Q_OBJECT
public:

 LinuxWebmPlayer(char* argv,int pos);

signals:
    void send_cluster_size_frames(long);
    void yes();


public slots:
   void add_packeges(Video_Bytes_Package);
   void set_video_info(Info);

Answer 1

我发现了问题，我的 DownloadWebm 对象中没有事件循环，所以当发出信号时，对象已完成执行。

Qt 信号发出但插槽从未调用

Qt signal emitted but slot never called

c++

qt

signals-slots