Swift 语法

根据类名来实例化对象，比如，要根据一个类名的字符串创建ViewController实例。

let controllerName="SpainAppProto."+xibName  // xibName 形如 XXViewController
var classType: AnyObject.Type=NSClassFromString(controllerName)
var nsobjectype : UIViewController.Type = classType as UIViewController.Type
var viewController: UIViewController = nsobjectype(nibName: xibName, bundle: nil) 

但是 在根据 UIViewController.self 来实例化的时候就要稍微转化下

    var x: String = m.debugDescription  // m为 UIViewController.self
    x = x.stringByReplacingOccurrencesOfString("Optional(", withString: "")
    x = x.stringByReplacingOccurrencesOfString(")", withString: "")
    let anyClass: AnyClass = NSClassFromString(x)
    let viewControllerClass: UIViewController.Type = anyClass as UIViewController.Type
    let viewController = viewControllerClass()