<p>I am using a navigation controller, and I have the style set to :</p>

<pre><code>navController.navigationBar.barStyle = UIBarStyleBlackTranslucent;
</code></pre>

<p>But when I run my program, the navigation controller looks like it is on top of a white background, not my background. When I push a controller, left or right, all my view, the current one, shifts to the top exactly the size of the navigation bar. And it is there where I can see my background through the navigation controller bar. Any ideas? When my barStyle is  set to opaque, everything looks fine. I was thinking on setting my view frame a negative 'y' value, but I think there should a more elegant way.</p>

I believe the UINavigationController assumes that your controller view frames don't include the area beneath the navigation bar.
UIBarStyleBlackTranslucent is more often used for UIToolbar, so Apple probably didn't make it easy to use it nicely with UINavigationBar. You'll probably need to abandon the UINavigationController, or start hacking the frames (careful with rotations), if you want to reliably render under the bar area.
Also, if your intention is to hide the navigation bar after a few seconds, you'll have a
much
easier time if you make it fade out (like the Photos app) instead of trying to slide it up (like Mobile Safari). Trust me on that one... that took me a
lot
of time to learn the hard way.