UIKit Construct and manage a graphical, event-driven user interface for your iOS or tvOS app. UIKit은 iOS/tvOS앱을 사용자 인터페이스를 구현하고 이벤트를 관리하는 프레임워크다 Important Use UIKit classes only from your app’s main thread or main dispatch queue, unless otherwise indicated. This restriction particularly applies to classes derived from UIResponder or that involve manipulating your app’s user interface in any way ..