在Swift中并不提倡使用Runtime，而是像其他语言一样使用反射(Reflect)。当然，目前Swift中的反射还没有其他语言中的反射功能强大，不仅远不及OC的Runtime，离Java的反射也有一定的距离。

Swift的反射机制是基于一个叫 Mirror 的 struct 来实现的

//反射事例

//反射机制，取出类的名字，转换成类，还要强转成类的类型               //1.从Bundle取出项目的名字（命名空间 = “项目的名字”+“.”+"类名"）        //2.修改命名空间，TARGETS -> Build Setting -> 输入product name ->修改即可         print("\(Bundle.main.infoDictionary)")        let clsN = Bundle.main.infoDictionary?["CFBundleName"] as? String ?? ""                //3.let class NSClassFromString(className) as? class.Type        //4. let cls = class?.init()        let clsName = clsN + ".ViewController"        let cls = NSClassFromString(clsName) as? ViewController.Type        let vc = cls?.init()        window?.rootViewController = vc//        let vc = ViewController()//        window?.rootViewController = vc        window?.makeKeyAndVisible()//2.//MARK:添加子控制器    //反射机制，将控制器的属性添加到字典数组中,然后再创建一个存储有控制器的数组A，遍历存储有控制器所有属性的数组，并调用返回控制器的方法，添加到数组A中，并把数组赋值给viewControllers //----反射控制器的方法    //根据命名空间+"."+"类名"反射出类    //再设置类的title,image,文字大小     //再创建导航将根控制器添加上去，返回导航    func setupChildViewController (){        let array = [["clsName":"SinaHomeViewController","title":"首页","imageName":"tabbar_home"],["clsName":"SinaHomeViewController","title":"信息","imageName":"tabbar_message_center"],             ["clsName":"","title":"","imageName":""],            ["clsName":"SinaHomeViewController","title":"发现","imageName":"tabbar_discover"],["clsName":"SinaHomeViewController","title":"我","imageName":"tabbar_profile"]]                var arrayVc = [UIViewController]()        for dict in array{            arrayVc.append(addViewController(dict: dict))        }        viewControllers = arrayVc    }       func addViewController(dict:[String:String])-> UIViewController{        //判断字典中是否有title,类名，imageName        guard let clsName = dict["clsName"],             let title = dict["title"],             let imageName = dict["imageName"],             let cls = NSClassFromString(Bundle.main.nameSpace + "." + clsName) as? UIViewController.Type else{          return UIViewController()        }        let vc = cls.init()        vc.title = title        vc.tabBarItem.image = UIImage(named: imageName)        vc.tabBarItem.selectedImage = UIImage(named: imageName + "_selected")?.withRenderingMode(.alwaysOriginal)        vc.tabBarItem.setTitleTextAttributes([NSForegroundColorAttributeName:UIColor.black], for: .normal)        let nav = SinaNavController(rootViewController: vc)        return nav    }