I've just found a great Android app which make my touch phone become a keyboard and mouse to control my Ubuntu PC. It's is RemoteDroid.
* Firstly, download and run the server app on your machine: http://remotedroid.net/
* Second, install the RemoteDroid app on your Android phone: https://play.google.com/store/apps/details?id=com.joshsera&feature=search_result#?t=W251bGwsMSwxLDEsImNvbS5qb3Noc2VyYSJd
* And finally, turn on the app on your phone, input the ip address of your computer. Enjoy the magic!!!!