![](/img/trans.png)
[英]QT signal-slot issue. Signal is emitted, slot isn't called. No warnings, no errors, no messages
[英]Qt signal emitted but slot never called
我想使用插槽和信號連接兩個對象(播放器和 DownloadWebm),但發生了一些奇怪的事情。 這是我的代碼:
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);
當我將 download_webm 連接到播放器時,插槽會接收到從 download_webm 發出的信號,但是當我嘗試將播放器連接到 download_webm 時,連接成功,會發出信號,但從不會調用來自 download_webm 的插槽。
這是我在 downloadwebm 中的信號聲明:
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) ;
和播放器 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);
我發現了問題,我的 DownloadWebm object 中沒有事件循環,所以當信號發出時 object 已經完成執行。
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.