Ok so, this is a little long but I will try my best to describe it.
With the new beta updates on android version of the game if you are on creative and want to take some items from creative inventory you click on them lets say, some blocks.
By clicking on them you get like a "courser" in-game with the items selected which you can move around to your player inventory from the creative one just like on Xbox or we'll, how java normally does with the usage of a mouse.
But, I connected my Xbox bluetooth controller to my phone to test some new features and just randomly build, and when I try to select from the creative inventory while using my controller (I press A on any creative inventory items) I get none on my "hand", it's just an useless click. I suppose if you are using a controller it is intended to work just like on console creating some sort of "cursor" that you can move the selected items around with the stick... by now, i click "A" on my controller slelecting an item and nothing happens, i have to use my finger to successfully choose any items.