How to display all hidden checkoboxes in a recyclerview on long press?

I made a layout for an item, with a hidden checkbox. On a long press, I want to make all checkboxes for all item in the recyclerview visible. I've tried to implement a long click listener but on a long press of an item only the check box for this specific item becomes visible.

• Adapter has 1 boolean to control visibility of checkbox in all items. If it is false, hide checkbox of the rows and vise versa
• When user long clicks on 1 item, change this boolean to true
• Right after that, call notifyDataSetChanged
• The list will display all checkboxes