If you're using an Android, get yourself an inexpensive USB-OTG cable. They're usually under £1. You can then plug in a keyboard & mouse (and anything else) to your Android phone.

If you have an MHL compatible device, you can also plug in an HDMI cable and use a bigger screen.

Something like http://amzn.to/1SgkguB will do the job. Of course, you might need to VNC into something to get the UI you want!