[FIXED] Have QGraphicsItem receive ALL mouse moves?

Issue

I have a subclass of QGraphicsItem. By default, QGraphicsItem only receives mouseMoveEvents if the pointer is within the boundingRect of the item AND a mousePressEvent has also happened.

I want this subclass to receive ALL mouseMoveEvents that occur within the QGraphicsScene that it's a member of (preferably in item coordinates). Is this possible?

Solution

Yes. You can use QGraphicsItem::grabMouse() to ensure that you get all mouse events. If you do so, then Qt promises the following:

This item will receive all mouse events for the scene until any of the following events occurs:

• The item becomes invisible
• The item is removed from the scene
• The item is deleted
• The item call ungrabMouse()
• Another item calls grabMouse(); the item will regain the mouse grab when the other item calls ungrabMouse().

Answered By - cgmb