将CardView置于RecyclerView中，只有一个元素

I'm using a RecyclerView that contains CardViews with a TextView and a ImageView (Every card represents a city). I also have a onClickListener on every card that leads me to a list of museum in the city. (The RecyclerView is populated by an ArrayList). The list is a RecyclerView composed by the same Cardview that scrolls vertically.I'm using a RecyclerView that contains CardView