經過事件傳遞機制獲取視圖的控制器

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