Question

I’m implementing a drag and drop interface with Qt across X11 and Windows. The interface handles events such that it is not illegal for a user to drop a dragged object on an area which can’t handle drops.

In this case, Qt::IgnoreAction should therefore not be treated as an incorrect potential action. To communicate this fact to the user I need a way to stop Qt::ForbiddenCursor from displaying if the current Qt::DropAction is Qt::IgnoreAction.

There are three ways I can see to achieve this (in order of preference):

• To override the QCursor used for a drag with Qt::IgnoreAction to something other than Qt::ForbiddenCursor.
• To override the bitmap used for Qt::ForbiddenCursor. This is pretty dirty but would be an acceptable solution as long as I don’t have to delve into OS-specific configuration.
• To override the call made by Qt when a drag leaves a valid drop area (I assume that Qt does the equivalent of QDropEvent::setDropAction(Qt::IgnoreAction) in this case).

Could anyone suggest ways to acheive any of the above?

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Note: I have also attempted to use QApplication::setOverrideCursor() just before calling QDrag::exec(). This doesn’t seem to have any effect.

Answer 1

Check if QDragEnterEvent comes to application itself (install event filter on QApplication object). If it does, simply accept it and cursor will appear normal.