Digital signage requires removal of the Android home bar during playback. On IAdea devices you can reliably achieve this. On other devices the home bar is designed to bounce back as soon as user touches the playing content.
Below is a very simple, minimalistic Android APK that hides the home bar and displays "Hello World." To create it in the Android SDK environment, simply assign Theme.Black.NoTitleBar.FullScreen as the Theme property of your application.
The complete app is provided as an attachment below. When you run it you should simply see "Hello World, HelloWorldActivity!" shown in the upper-left-hand corner on a black, full-screen background. The home bar is gone until you exit the app.