twitter: [android-developers] two programming questions about 'twitter for android' app

1. what kind of layout do you think they used to get the animated icon
pinned to the bottom of the screen?
2. what view did they use for the icons on the main screen? i have
tried gridlayout and a linearlayout with icons, but i'm specifically
looking for the effect on focus where there is just a faint orange
glow around and behind the icon rather than the whole icon square
lighting up?

thanks!
eric