iOS에서 간단히 애니메이션을 구현하는 방법
// swift
let animationImages:[AnyObject] = [UIImage(named: "loading_outlink_01")!, UIImage(named: "loading_outlink_02")!, UIImage(named: "loading_outlink_03")!, UIImage(named: "loading_outlink_04")!]
loadingImageView.animationImages = animationImages
loadingImageView.animationDuration = 1.5
loadingImageView.animationRepeatCount = 0
loadingImageView.startAnimating()
self.addSubview(loadingImageView)
objective-c 는 아래 링크를 참조
http://stackoverflow.com/questions/6040528/animation-using-array-of-images-in-sequence