iPhone开发 - 限制用户与应用程序的交互并显示进度指示器

let alert = UIAlertController(title: "正在进行操作", message: "请稍候...", preferredStyle: .alert)
present(alert, animated: true, completion: nil)

let activityIndicator = UIActivityIndicatorView(style: .gray)
activityIndicator.center = view.center
view.addSubview(activityIndicator)
activityIndicator.startAnimating()

let hud = MBProgressHUD.showAdded(to: view, animated: true)
hud.label.text = "正在进行操作"
hud.mode = .indeterminate

let progressView = UIProgressView(progressViewStyle: .default)
progressView.frame = CGRect(x: 0, y: view.bounds.height - 20, width: view.bounds.width, height: 20)
progressView.progress = 0.5
view.addSubview(progressView)