iOS grouped buttons

I'd like to have a UINavigationBar at the top of my application, and below it I'd like to have something that looks like a navigation bar, but with buttons on it, like the bottom of the Maps application on the iPhone. How do you group buttons 开发者_JAVA百科in this manner?

Simple. Use a UISegmentedControl.

I've created a second UINavigationBar below the main UINavigationBar. Then just add a UISegmentedControl to the second UINavigation bar. I'm not sure if UINavigationBar is supposed to be used this way, but it looks and works fine. I've the technique in several apps.