Hello!
I personally wouldn't bother with an adapter thing. You can get good full-disk shots just by holding your phone up to the eyepiece. I've taken a few shots with various phones over the years just by holding them up to the eyepiece and they've turned out surprisingly well - especially with my latest GS7.
Of course if you want to get more than full-disk shots you'd need one of those adapters but I'd say if you're getting into it enough for that then you're better off saving that money and putting it towards a DSLR or a planetary/lunar imaging camera.