Qt - QGridLayout access element at coordinates

Question

I have a QGridLayout with a constant number of rows and columns that is filled with instances of QToolButton. What I want to do is to access an object within this layout whose location is determined by its coordinates. I know that there is QGridLayout::->itemAtPosition(row, column) that returns a pointer to QLayoutItem but once I cast it to a QToolButton (which it is, obviously) and try to change something within it I get an access violation exception.

This is how I've tried to cast QLayoutItem* to QToolButton*:

QToolButton* button = dynamic_cast<QToolButton*>(_ui.gridLayoutLeft->itemAtPosition(x, y)); // gridLayoutLeft is of type QGridLayout*

static_cast gave me an "Invalid type conversion" error. What can be done to achieve this behavior?

I'm using VS 2013 with the latest Qt available.

Answer 1

Try this:

QLayoutItem* item = _ui.gridLayoutLeft->itemAtPosition(x, y);
QWidget* widget = item->widget();
QToolButton* button = dynamic_cast<QToolButton*>(widget); 

In real code don't forget to check for valid pointers.