how to find an item in the scene

Question

How I can find a particular item in the scene and remove it . I have declared a graphicsitem and added it to the scene. Now in certain case I have to remove the item from the scene but before removing the item from the scene I want to know the item is added to scene or not. If I try to remove the item which is not added to the scene, I get the below error:

"QGraphicsScene::removeItem: item 0x121c520's scene (0x0) is different from this scene (0x1143850)"

the item is not selected so I can not use the scene()->selectedItem() list.

Answer 1

You can check the pointer returned from calling QGraphicsItem::scene(). It will either return the scene, or NULL if it is not present in a scene.

// assuming item is a class derived from QGraphicsItem
if(item->scene() != nullptr) // nullptr from C++ 11, else use NULL
{
    // item is in a scene
}