Hi Stefaan,
We have checked the reported query “Expand the item size of the listview when tap an item in grid layout without affecting the other item in a row” from our end. We highly regret to let you know that your requirement is not possible, because in GridLayout column width is equally splits and height is taken from the highest height of the item loaded in the single row. Your requirement can be achieved by staggered layout support.
Current we don't have support for staggered layout in ListView. We have already considered the “Provide support for Staggered Layout” as feature and added it to our feature request list. It can be tracked through our Features Management System:
Note: Feature implementation is tentative and not a commitment on our parts. We do not have immediate plans for this feature implementation due to preplanned tasks. We will update you once the feature has been implemented.
Regards,
Jayaleshwari N.