How to change navigation bar color in iOS 7 or 6?

I want to change the color of the navigation bar color, but I'm not sure whether or not I should change the tint or the background. I know iOS 7 is going for a more flat design (even recommending removing gradients), but I am having trouble deciphering the two. Even if I set a background color, it doesn't do anything.

In this image, the background is set to green, but the bar is still blue:

The behavior of tintColor for bars has changed on iOS 7.0. It no longer affects the bar's background and behaves as described for the tintColor property added to UIView. To tint the bar's background, please use -barTintColor.

navController.navigationBar.barTintColor = [UIColor navigationColor];

If you want to have a solid color for your navigation bar in iOS 6 similar to iOS 7 use this:

[[UINavigationBar appearance] setBackgroundImage:[[UIImage alloc] init] forBarMetrics:UIBarMetricsDefault];
[[UINavigationBar appearance] setBackgroundColor:[UIColor greenColor]];

in iOS 7 use the barTintColor like this:

navigationController.navigationBar.barTintColor = [UIColor greenColor];

or

 [[UINavigationBar appearance] setBarTintColor:[UIColor greenColor]];

// In ios 7 :-

[self.navigationController.navigationBar setBarTintColor:[UIColor yellowColor]];

// In ios 6 :-

[self.navigationController.navigationBar setTintColor:[UIColor yellowColor]];

The background color property is ignored on a UINavigationBar, so if you want to adjust the look and feel you either have to use the tintColor or call some of the other methods listed under "Customizing the Bar Appearance" of the UINavigationBar class reference (like setBackgroundImage:forBarMetrics:).

Be aware that the tintColor property works differently in iOS 7, so if you want a consistent look between iOS 7 and prior version using a background image might be your best bet. It's also worth mentioning that you can't configure the background image in the Storyboard, you'll have to create an IBOutlet to your UINavigationBar and change it in viewDidLoad or some other appropriate place.