如何使用 C + + QT 获取鼠标坐标？

Question

void Window::acquire(QMouseEvent * event)
{
    pos_xy->setText(QString("coordinates：（%1,%2）").arg(event->pos().x()).arg(event->pos().y()));
}

Window is the inheritance class of QWidget, and the above code is a member function of this class。pos_xy is a QLineEdit *.

i want to get the coordinates of the mouse click,but i don't know how to call the acquire function when the mouse clicked.

Thanks in advance！

Answer 1

If you want to be notified whenever the user clicks anywhere inside the window, you can implement that behavior using an event filter . For example, you could create a class like this:

#include <QObject>
#include <QMouseEvent>

class MouseWatcher : public QObject
{
public:
   MouseWatcher(QWidget * parent) : QObject(parent) {/* empty */}

   virtual bool eventFilter(QObject * obj, QEvent * event)
   {
      if (event->type() == QEvent::MouseButtonPress)
      {
         QMouseEvent * me = static_cast<QMouseEvent *>(event);
         QPointF windowPos = me->windowPos();
         printf("User clicked mouse at %f,%f\n", windowPos.x(), windowPos.y());
      }
      return QObject::eventFilter(obj, event);
   }
};

... and then install it as a filter on your window object, like this:

MyWindowObject * win = [...];
MouseWatcher * mw = new MouseWatcher(win);
win->installEventFilter(mw);

... and now it will print the window-relative mouse co-ordinates to stdout every time the user clicks on the window.