On-screen keyboard in Ubuntu 14.04 LTS?

Under Microsoft Windows 8, our Sony VAIO Tap 20 (a touch-screen desktop computer) automatically displays an on-screen keyboard if one touches a text field on-screen or there is otherwise no keyboard available (for example, the included bluetooth keyboard is switched-off or flat)... There is also a (notification area/system tray-based) option to display or hide the on-screen keyboard on-demand.

Does such functionality exist under Ubuntu 14.04 LTS ("Trusty Tahr")?

My understanding is that Ubuntu 14.04 LTS ("Trusty Tahr") is supposed to be a mostly smartphone/tablet-focused upgrade... But for the life of me, I cannot find functionality that replicates that of Windows 8 (as described above)!

I've finally convinced the wife to let me single-boot Ubuntu on our VAIO Tap 20, but the included bluetooth keyboard smashes through batteries like they're going out of fashion, so until we can buy a corded keyboard, we need a solution (preferably built-in) that replicates the functionality found under Windows 8...

--

Never mind - all one needs to do after @Rmano 's solution is log-out and log back in... I should also note that this was already installed under Ubuntu 14.04 LTS ("Trusty Tahr").

The relevant program should be "onboard". You can install it by:

sudo apt-get install onboard 

and launch it with "onboard" or from the Dash. I have Xubuntu here so I cannot check, but should be possible to enable it under "assistive technologies" or similar in the menu.

The panel icon let you access an extensive set of features. Never tried it (I do not have a touchscreen PC) but seems ok --- I used it sporadically to type things that could not type in a remote VNC session for layout problems.

On screen keyboard is already available in Ubuntu 14.04

If you run,sudo apt-get install onboard

Reading package lists... Done
Building dependency tree       
Reading state information... Done
onboard is already the newest version

To open onboard:

Open terminal and run:onboard

or from dash: