When you placed any cubic blocks on the ground and you add an Item Frame on the block then you try to put a Redstone Dust/Carpet in the position where the + sign or the cursor in the photo is pointing on, the Redstone Dust/Carpet will not be placed on it. (On Minecraft PC and other Minecraft in different consoles you will be able to put a Redstone Dust/Carpet in the position where the + sign or the cursor in the photo is pointing on.) I'm currently using Tablet - Android - Lenovo Tab A7.