Qt中奇怪的光标行为

Question

In Qt (C++, MinGW, Windows 7), QCursor::setPos(...) seems to change the position of the cursor at the application level but not at the system level. For example, if you intercept the mouseMoveEvent and cancel out the movement of the cursor (with setMouseTracking(false) such that you do this cancellation only when a mouse button is pressed), then you'll see no cursor move as long as you maintain the mouse button pressed. But then, when you release the button and move a little, the cursor will go to the place it would have been if you haven't blocked its movement. Is this behavior normal? How to get around it such that the mouse cursor is changed at the system level?

If it is not clear enough, I can give code snippet.

Answer 1

Moving the cursor of a QWidget always uses the widget's coordinates. For global mouse positioning, you should use the desktop widget (QDesktopWidget) instead. You can get it through the QApplication::desktop() static function. Example:

QApplication::desktop()->cursor().setPos(0,0);

This should move the mouse cursor to the top-left corner of the desktop.