Question

我有这段代码：

类CMyWindow：

class CMyWindow: public QMainWindow
{ // Q_OBJECT .... here  
private:
    CMyServer *server;
public:
    CMyWindow(QWidget *parent): QMainWindow(parent)
    {
        // Setup GUI here
        server = new CMyServer(this);
        server->startServer();
    }
    void thisChangeLabelCaption(QString str) {
        ui.lblStatus.setText(str);
    }
}

和类CMyServer：

class CMyServer: public QTcpServer
{       
protected:
    void incomingConnection(int sockDesc) {
        /* Why below line can't be done :-| */
        ((CMyWindow *) parent())->thisChangeLabelCaption("New connection");
    }
}

但是incomingConnection（）rountine中的行似乎没有执行。

请告诉我这个问题的解决方法。

更新正如@vtmarvin所说，我试过这种方式：

class CMyWindow: public QMainWindow
{
private:
    CMyServer *server;
protected slots:
    void editLabel(QString str) {
        thisChangeLabelCaption(str);
    }

public:
    CMyWindow(QWidget *parent): QMainWindow(parent) {
        server = new CMyServer(this);
        server->startServer();
    }

    void thisChangeLabelCaption(QString str) {
        ui.lblStatus.setText(str);
    }
}

class CMyServer: public QTcpServer
{
Q_SIGNAL:
    void setText(QString str);

protected:
    void incomingConnection(int sockDesc) {
        /* Why below line can't be done :-| */
        emit setText("New connection");
    }

public:
    CMyServer(QObject *parent): QTcpServer(parent)
    {
        connect(this, SIGNAL(setText(QString)), parent, SLOT(editLabel(QString)), Qt::QueuedConnection);
    }
}

但没有更好的结果： - （

Answer 1

You cannot change UI from other threads than the main one - 拥有QMainWindow的人。我想你的CMyServer :: incomingConnection是由QTcpServer线程调用的。您必须使用Qt :: QueuedConnection类型执行信号槽。

Qt4.8中的跨线程问题

1 个答案: