UIViewAddition里的viewcontroller方法是否存在遗漏

[feiadan]

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

这样是不是更准确一点。