How to set Recyclview items on TextView in android

This is my main screen and i want when i click on Select All checkbox then check all checkboxes and set all checkbox's text on below textView(Just text). I successfully select all checkboxes but can't set text on textbox with separate commas, with the help of adapter i get the list of whole data but can't set it on main activity textview layout. plz suggest me any helpful way for done this. Thnakyou.