NSString *strClass = NSStringFromClass([self class]); // 把当前类封装成字符串
UIViewController *viewController = NSClassFromString(strClass); // 把字符串 转换成 class
NSString *strClass = NSStringFromClass([self class]); // 把当前类封装成字符串
UIViewController *viewController = NSClassFromString(strClass); // 把字符串 转换成 class