test1.swift

@objc func touchUpStartButtonAction() {
        print("start")
        
        for url in imageUrls {
            let image = UIImage(contentsOfFile: url!.relativePath)
            print(url!.relativePath)
            self.loadingView!.imageView.image = image
            self.loadingView!.setNeedsDisplay()
            var t = 0
            for i in 0 ... 5000000 {
                t += i
            }
            print(t)
        }
        
        print("end")
    }