HTML/CSS is to web apps as "what" is to ios apps?

I've been working with HTML/CSS for a while now...prim开发者_如何转开发arily for UI web app projects. Then I hand the HTML/CSS over to the developer (PHP, Python, Ruby, etc) who ties it all in.

What does one use to create a UI for an ios app? I know that native ios apps are created in objective C, but what about their user interfaces?

Thanks in advance for any guidance you can offer.

Eddie

User interfaces in native iOS apps are created using Interface Builder on Mac OS X. The UIs that you create are made up of native Cocoa Touch/UIKit objects (UIButton, UIView, UITextField, etc) which are serialized into an XML format. Interface Builder lets you define and configure these objects and save them in XML format as a .xib file. When the native app wants to display the UI, it reads your .xib and deserializes the objects stored within.

Since Interface Builder is just playing around with actual Objective-C objects, you can skip it entirely by directly creating objects in your code and programmatically adding them to the window. (Obviously, this can get complicated pretty quick if you aren't careful.)