QTimer 在主函数之外不起作用
QTimer doesn't work outside main function
简而言之:这段代码位于主函数中,效果很好。此代码对两个图形元素执行交换。
QTimer timer;
timer.setTimerType(Qt::PreciseTimer);
timer.setInterval(1000.0/30.0);
timer.setSingleShot(false);
// ====================== MOVE 4 in POS of 1 ==========================
QPointF centre(QLineF(button1->pos(), button4->pos()).pointAt(0.5));
QPointF positionBut4 = button4->pos();
MyPointF centreSwap4(0, &positionBut4, ¢re);
button4->myPointF = ¢reSwap4;
QObject::connect(&timer, SIGNAL(timeout()), ¢reSwap4, SLOT(updateDownRight()));
QObject::connect(¢reSwap4, SIGNAL(positionChanged()), button4, SLOT(slotMoveCircle()));
// ====================== MOVE 4 in POS of 1 ==========================
// ====================== MOVE 1 in POS of 4 ==========================
QPointF positionBut1 = button1->pos();
MyPointF centreSwap1(0, &positionBut1, ¢re);
button1->myPointF = ¢reSwap1;
QObject::connect(&timer, SIGNAL(timeout()), ¢reSwap1, SLOT(updateUpLeft()));
QObject::connect(¢reSwap1, SIGNAL(positionChanged()), button1, SLOT(slotMoveCircle()));
// ====================== MOVE 1 in POS of 4 ==========================
timer.start();
QTimer::singleShot(3000, Qt::PreciseTimer, &timer, SLOT(stop()));
但是当我想将这段代码从 main 中放到一个函数中时(为了缩短代码并通过仅提供指向元素的指针来对元素执行交换)QTimer 拒绝工作(说它处于活动状态但超时未触发):
void animateSwap(QGraphicsRectWidget *w1, QGraphicsRectWidget *w2, QTimer &timer)
{
QGraphicsRectWidget *button4, *button1;
if (w1->x() > w2->x())
{
button4 = w2;
button1 = w1;
}
else
{
button4 = w1;
button1 = w2;
}
// ====================== MOVE w2 in POS of w1 ==========================
QPointF centre(QLineF(button1->pos(), button4->pos()).pointAt(0.5));
QPointF positionBut4 = button4->pos();
MyPointF centreSwap4(0, &positionBut4, ¢re);
button4->myPointF = ¢reSwap4;
QObject::connect(&timer, SIGNAL(timeout()), ¢reSwap4, SLOT(updateDownRight()));
QObject::connect(¢reSwap4, SIGNAL(positionChanged()), button4, SLOT(slotMoveCircle()));
// ====================== !MOVE w2 in POS of w1 ==========================
// ====================== MOVE w1 in POS of w2 ==========================
QPointF positionBut1 = button1->pos();
MyPointF centreSwap1(0, &positionBut1, ¢re);
button1->myPointF = ¢reSwap1;
QObject::connect(&timer, SIGNAL(timeout()), ¢reSwap1, SLOT(updateUpLeft()));
QObject::connect(¢reSwap1, SIGNAL(positionChanged()), button1, SLOT(slotMoveCircle()));
// ====================== MOVE w1 in POS of w2 ==========================
timer.start();
qDebug() << timer.isActive();
QTimer::singleShot(3000, Qt::PreciseTimer, &timer, SLOT(stop()));
}
更新:
现在有效了:
void animateSwap(QGraphicsRectWidget *w1, QGraphicsRectWidget *w2, QTimer &timer, int cycles = 1)
{
QGraphicsRectWidget *button4, *button1;
if (w1->x() > w2->x())
{
button4 = w2;
button1 = w1;
}
else
{
button4 = w1;
button1 = w2;
}
// ====================== MOVE w2 in POS of w1 ==========================
QPointF centre(QLineF(button1->pos(), button4->pos()).pointAt(0.5));
QPointF positionBut4 = button4->pos();
MyPointF *centreSwap4 = new MyPointF(0, &positionBut4, ¢re);
button4->myPointF = centreSwap4;
QObject::connect(&timer, SIGNAL(timeout()), centreSwap4, SLOT(updateDownRight()));
QObject::connect(centreSwap4, SIGNAL(positionChanged()), button4, SLOT(slotMoveCircle()));
// ====================== !MOVE w2 in POS of w1 ==========================
// ====================== MOVE w1 in POS of w2 ==========================
QPointF positionBut1 = button1->pos();
MyPointF *centreSwap1 = new MyPointF(0, &positionBut1, ¢re);
button1->myPointF = centreSwap1;
QObject::connect(&timer, SIGNAL(timeout()), centreSwap1, SLOT(updateUpLeft()));
QObject::connect(centreSwap1, SIGNAL(positionChanged()), button1, SLOT(slotMoveCircle()));
// ====================== MOVE w1 in POS of w2 ==========================
timer.start();
qDebug() << timer.isActive();
QTimer::singleShot(3000 * cycles, Qt::PreciseTimer, &timer, SLOT(stop()));
}
您正在将定时器的 timeout() 信号连接到例如
MyPointF centreSwap1(0, &positionBut1, ¢re);
它是堆栈上的一个对象,因此是函数的局部对象,并在函数完成时被删除。如果其中一个对象(发送方、接收方)被删除,Qt 将断开连接,因此当定时器结束时,没有任何连接到它的 timeout() 信号。
简而言之:这段代码位于主函数中,效果很好。此代码对两个图形元素执行交换。
QTimer timer;
timer.setTimerType(Qt::PreciseTimer);
timer.setInterval(1000.0/30.0);
timer.setSingleShot(false);
// ====================== MOVE 4 in POS of 1 ==========================
QPointF centre(QLineF(button1->pos(), button4->pos()).pointAt(0.5));
QPointF positionBut4 = button4->pos();
MyPointF centreSwap4(0, &positionBut4, ¢re);
button4->myPointF = ¢reSwap4;
QObject::connect(&timer, SIGNAL(timeout()), ¢reSwap4, SLOT(updateDownRight()));
QObject::connect(¢reSwap4, SIGNAL(positionChanged()), button4, SLOT(slotMoveCircle()));
// ====================== MOVE 4 in POS of 1 ==========================
// ====================== MOVE 1 in POS of 4 ==========================
QPointF positionBut1 = button1->pos();
MyPointF centreSwap1(0, &positionBut1, ¢re);
button1->myPointF = ¢reSwap1;
QObject::connect(&timer, SIGNAL(timeout()), ¢reSwap1, SLOT(updateUpLeft()));
QObject::connect(¢reSwap1, SIGNAL(positionChanged()), button1, SLOT(slotMoveCircle()));
// ====================== MOVE 1 in POS of 4 ==========================
timer.start();
QTimer::singleShot(3000, Qt::PreciseTimer, &timer, SLOT(stop()));
但是当我想将这段代码从 main 中放到一个函数中时(为了缩短代码并通过仅提供指向元素的指针来对元素执行交换)QTimer 拒绝工作(说它处于活动状态但超时未触发):
void animateSwap(QGraphicsRectWidget *w1, QGraphicsRectWidget *w2, QTimer &timer)
{
QGraphicsRectWidget *button4, *button1;
if (w1->x() > w2->x())
{
button4 = w2;
button1 = w1;
}
else
{
button4 = w1;
button1 = w2;
}
// ====================== MOVE w2 in POS of w1 ==========================
QPointF centre(QLineF(button1->pos(), button4->pos()).pointAt(0.5));
QPointF positionBut4 = button4->pos();
MyPointF centreSwap4(0, &positionBut4, ¢re);
button4->myPointF = ¢reSwap4;
QObject::connect(&timer, SIGNAL(timeout()), ¢reSwap4, SLOT(updateDownRight()));
QObject::connect(¢reSwap4, SIGNAL(positionChanged()), button4, SLOT(slotMoveCircle()));
// ====================== !MOVE w2 in POS of w1 ==========================
// ====================== MOVE w1 in POS of w2 ==========================
QPointF positionBut1 = button1->pos();
MyPointF centreSwap1(0, &positionBut1, ¢re);
button1->myPointF = ¢reSwap1;
QObject::connect(&timer, SIGNAL(timeout()), ¢reSwap1, SLOT(updateUpLeft()));
QObject::connect(¢reSwap1, SIGNAL(positionChanged()), button1, SLOT(slotMoveCircle()));
// ====================== MOVE w1 in POS of w2 ==========================
timer.start();
qDebug() << timer.isActive();
QTimer::singleShot(3000, Qt::PreciseTimer, &timer, SLOT(stop()));
}
更新: 现在有效了:
void animateSwap(QGraphicsRectWidget *w1, QGraphicsRectWidget *w2, QTimer &timer, int cycles = 1)
{
QGraphicsRectWidget *button4, *button1;
if (w1->x() > w2->x())
{
button4 = w2;
button1 = w1;
}
else
{
button4 = w1;
button1 = w2;
}
// ====================== MOVE w2 in POS of w1 ==========================
QPointF centre(QLineF(button1->pos(), button4->pos()).pointAt(0.5));
QPointF positionBut4 = button4->pos();
MyPointF *centreSwap4 = new MyPointF(0, &positionBut4, ¢re);
button4->myPointF = centreSwap4;
QObject::connect(&timer, SIGNAL(timeout()), centreSwap4, SLOT(updateDownRight()));
QObject::connect(centreSwap4, SIGNAL(positionChanged()), button4, SLOT(slotMoveCircle()));
// ====================== !MOVE w2 in POS of w1 ==========================
// ====================== MOVE w1 in POS of w2 ==========================
QPointF positionBut1 = button1->pos();
MyPointF *centreSwap1 = new MyPointF(0, &positionBut1, ¢re);
button1->myPointF = centreSwap1;
QObject::connect(&timer, SIGNAL(timeout()), centreSwap1, SLOT(updateUpLeft()));
QObject::connect(centreSwap1, SIGNAL(positionChanged()), button1, SLOT(slotMoveCircle()));
// ====================== MOVE w1 in POS of w2 ==========================
timer.start();
qDebug() << timer.isActive();
QTimer::singleShot(3000 * cycles, Qt::PreciseTimer, &timer, SLOT(stop()));
}
您正在将定时器的 timeout() 信号连接到例如
MyPointF centreSwap1(0, &positionBut1, ¢re);
它是堆栈上的一个对象,因此是函数的局部对象,并在函数完成时被删除。如果其中一个对象(发送方、接收方)被删除,Qt 将断开连接,因此当定时器结束时,没有任何连接到它的 timeout() 信号。