c++ - Qt C++ QTimer 不调用处理程序

Question

我的 Qt C++ 中的 QTimer 有问题，在我的代码中没有调用 timeoutHandler()。谁能告诉我为什么以及如何解决它？

测试.h

class Test : public QObject
{
    Q_OBJECT
private:
    static bool timeOuted;
public:
    explicit Test(QObject *parent = 0);
    virtual ~Test();
public slots:
    static void handleTimeout();
};

测试.cpp

void Test::run()
{
    QTimer::singleShot(3000, this, SLOT(handleTimeout()));
    while(!timeOuted);
    if(timeOuted)
    {
        timeOuted = false;
    }
    else
    {
       /* some work */
    }
}

bool Test::timeOuted = false;

void Test::handleTimeout()
{
    static int i = 0;
    timeOuted = true;
    qDebug() << "TimeOuted " << i++;
}

Answer 1

QTimer 需要 Qt 事件循环才能工作。当您进入 while(!timeOuted); 时，您会无休止地阻塞当前线程，并且 Qt 的事件循环没有机会采取任何操作(例如调用计时器的处理程序)。以下是您应该如何操作:

测试.h:

class Test : public QObject
{
    Q_OBJECT
public:
    explicit Test(QObject *parent = 0);
    virtual ~Test();

    void run(); // <-- you missed this
private slots: // <-- no need to make this slot public
    void handleTimeout(); // <-- why would you make it static?!
};

测试.cpp:

void Test::run()
{
    QTimer::singleShot(3000, this, SLOT(handleTimeout()));
}

void Test::handleTimeout()
{
    static int i = 0;
    qDebug() << "TimeOuted " << i++;

    /* some work */
}