I have an app which have a UINavigationBar and I have set the tint color to black like this:
self.navigationController.navigationBar.tintColor = [UI
You need to set the barTintColor property.
You can specify a custom tint color for the navigation bar background using the Tint (barTintColor) field. The default background tint color is white.
From iOS7 docs: https://developer.apple.com/library/content/documentation/UserExperience/Conceptual/UIKitUICatalog/UINavigationBar.html#//apple_ref/doc/uid/TP40012857-UINavigationBar-SW1