I need to clarify my question. I'm wondering if there are any apps for smartphone that can log each 'keystroke' (i.e. key pressed on touchscreen) that a user does. Performing a google search brings up some links to sites like this and this. These apps do not record keystrokes, they 'only' forward sms messages, call logs, contacts and so on to the attacker. Although they call themselves keylogger, that's not what I mean.
Are 'keyloggers' impossible due to the fact that there are no 'real' keystrokes to log? Is this kind of attack simply not possible on touchscreens?