一、实现原理：
通过消息响应者链找到UIView所在的UIViewController

• UIView类继承于UIResponder,通过UIResponder的next方法来获取UIViewController.
• 如果next返回是空，则继续向上遍历superview并再次使用next方法获取。这样一直找下去，直到找到或抛出异常。

二、实现代码

• 通过扩展UIView,给其添加个viewController方法，从而让我们可以获得任意视图对象（View）所属视图控制器

Swift

func viewController() -> UIViewController? {
    for view in sequence(first: self.superview, next: { $0?.superview }) {
        if let responder = view?.next {
            if responder.isKind(of: UIViewController.self){
                return responder as? UIViewController                   
            }
        }
    }
    return nil
}

Objective-C

-(UIViewController *)viewController{
    UIViewController *viewController = nil;
    UIResponder *next = self.nextResponder;
    while (next) {
        if ([next isKindOfClass:[UIViewController class]]) {
            viewController = (UIViewController *)next;
            break;
        }
        next = next.nextResponder;
    }
    return viewController;
}