iOS 8 Keyboards Can’t Implement SwipeSelection
Andrei Puni (via Clark Goble):
Your custom keyboard does not have access to the view hierarchy of the input, it cannot control the cursor and select text.
I’m really surprised that Apple hasn’t improved text selection yet.
Update (2014-07-08): Ole Zorn:
Looks like it's possible to move the cursor with a custom keyboard in beta 3. :)