Here’s an open source library that allows you to very quickly apply a them to your UIKit interface components by simply supplying your chosen colors, and font.

As the readme states:

MAThemeKit provides iOS developers the ability to create a coherent color theme throughout their entire application using a single line of code, removing the need to mess with the dozens of UIAppearance proxies for each UI component.

Here’s an image from the readme showing a themed interface:

And the code used to create this theme:

[MAThemeKit setupThemeWithPrimaryColor:[MAThemeKit colorWithR:0 G:184 B:156] secondaryColor:[UIColor whiteColor] fontName:@"HelveticaNeue-Light" lightStatusBar:YES];

You can find MATHemeKit on Github here.