Virtual/soft buttons for (Home, menu,Back, Search) always on top?

How can I make an app or maybe service that looks like (Nexus One touch buttons) for the navigation keys (Home, menu,Back, Search)

The buttons should always be visibly and always stay on top and send the command to the app thats running.

Someone have ideas and sample codes how to do that?

* I see an app with name (Smart Taskmanager) wich always detect when you touch the right side of the screen and then detect when you slide the finger to left.

So I think its possible, with this function I think its possible to implementate the code to simulate the (Home, Meny, Back, Search) buttons.

* I also see and test an app wich show a "cracked display" always ontop so that tecnic maybe shold be useful to always show the buttons/bitmanp on top.

Thoose function开发者_StackOverflow社区, to show the button and catch the "touch event" and send the event to the active program, thats what i dont can figure out how to do.

How can I make an app or maybe service that looks like (Nexus One touch buttons) for the navigation keys (Home, menu,Back, Search)

An SDK application cannot do this, sorry.

Most of this question is answered here: Moving the Hard Button Functionality (Home,Back,Search<Menu) to soft buttons in android