c++ - QT5 中的信号和插槽

Question

我遇到了以下问题:

我有一个 GUI 元素类和一个 Thread 类。我想在它们之间交换信号。然而，它只在一个方向上起作用。我可以成功地将信号从主 GUI 窗口发送到线程。但是，当我想从线程向调用线程的进程发送信号时，它不起作用。这是我的做法:

bool GfxMapItem::mapSwitch(int seqidx)
{
    ...
importMapThread_ = new ImportMapThread(sequence_->item(seqidx)); 
connect(GUI_UI->analExportButton,  SIGNAL(clicked()), importMapThread_, SLOT(interrupt1()), Qt::QueuedConnection); //<-- this one works perfectly 
connect(importMapThread_,  SIGNAL(progress(int)), this, SLOT(loadMap(int)), , Qt::QueuedConnection); // <-- this one unfortunatelly doesn't 
    ... 
} 

线程代码非常简单，它只发出信号(当我将线程与自身连接时，我检查过它是否有效)。

void ImportMapThread::run()
{
QLOGX("Running ImportMapThread..."); 
QLOGINC; 
emit this->progress(100); 

QLOGX("Stopping ImportMapThread..."); 
} 

线程标题如下所示:

class ImportMapThread : public InterruptibleThread
{
Q_OBJECT

private: 
...

protected:
...

public:
ImportMapThread(SeqItem *p); 

signals: 
void progress(int value); 
void progressReset(int value); 

public slots: 
     virtual void interrupt1(); 
 void loadMap();  

protected: 
virtual void run(); 
}; 

调用该线程的类如下所示:

class GfxMapItem : public QObject, public QGraphicsPixmapItem
{
Q_OBJECT
...

signals:
void mouseOutside();
void mouseMove(const QPointF &pos);

private slots: 
void loadMap(int); 

protected:
...
}; 

有什么想法吗？拜托，我已经没有想法了。

Answer 1

我相信，您应该在运行实现中调用 exec。 Exec 启动事件循环，应该允许发送信号。

看看:

int QThread::exec() [protected] Enters the event loop and waits until exit() is called, returning the value that was passed to exit(). The value returned is 0 if exit() is called via quit(). It is necessary to call this function to start event handling.

希望对您有所帮助。