Swift doesn&#x27;t have the slightest concept of UI. If you want to do UI work in Swift, you use whatever UI frameworks are available on your target platform. Since Swift interoperates very nicely with C and Objective-C, those frameworks can be written in those languages and still be usable from Swift. On OS X the framework happens to be Cocoa, but Swift isn&#x27;t in any way tied to it.<p>On Android, Swift will likely be in the same position as the NDK, which isn&#x27;t a great place to be for UI, but it&#x27;s doable. You&#x27;ll be able to make the same UI calls you&#x27;d make from C code.