Question

我有以下课程：

class MainWindow : public QMainWindow
{

public:
void StartTimer()
{
     timer = new QTimer(this);
     timer.start(100);

}

private:
QTimer *timer;

};


class AnotherClass
{

public:
MainWindow *window;
void runTimer()
{
    window->StartTimer();
}


};

假设窗口指针正确指向主窗口，如果我尝试调用runTimer()，则会收到此错误：

QObject: Cannot create children for a parent that is in a different thread.
(Parent is MainWindow(0x7fff51ffe9f0), parent's thread is QThread(0x7fd1c8d001d0), current thread is QThread(0x7fd1c8f870c0)
QObject::startTimer: Timers can only be used with threads started with QThread

我对这个错误的猜测是，因为runTimer是从另一个线程调用的，所以它也试图在同一个线程中初始化？而不是主窗口线程？

如果我在主窗口的默认构造函数中初始化计时器，我会收到

QObject::startTimer: Timers cannot be started from another thread

如何告诉QTimer从另一个班级开始？

Answer 1

您可以使用信号和插槽。

class AnotherClass : public QObject
{

    Q_OBJECT

public:

    MainWindow * window;

    AnotherClass() : window( new MainWindow )
    {
        // Connect signal to slot (or just normal function, in this case )
        connect( this, &AnotherClass::signalStartTimer,
                 window, &MainWindow::StartTimer,
                 // This ensures thread safety, usually the default behavior, but it doesn't hurt to be explicit
                 Qt::QueuedConnection );

        runTimer();
    }

    void runTimer()
    {
        emit signalStartTimer();
    }

signals:

    void signalStartTimer();

};

从另一个类开始QTimer

1 个答案: