iOS10 去除导航栏下的黑线

    //去掉导航栏下面黑线
    if ([self.navigationController.navigationBar respondsToSelector:@selector( setBackgroundImage:forBarMetrics:)])
    {
        
        NSArray *list=self.navigationController.navigationBar.subviews;
        
        for (id obj in list)
        {
            
            if ([UIDevice currentDevice].systemVersion.floatValue >= 10.0)
            {//10.0的系统字段不一样
                UIView *view =   (UIView*)obj;
                for (id obj2 in view.subviews) {
                    
                    if ([obj2 isKindOfClass:[UIImageView class]]) {
                        
                        UIImageView *image =  (UIImageView*)obj2;
                        image.hidden = YES;
                    }
                }
            }else
            {
                
                if ([obj isKindOfClass:[UIImageView class]])
                {
                    
                    UIImageView *imageView=(UIImageView *)obj;
                    NSArray *list2=imageView.subviews;
                    for (id obj2 in list2)
                    {
                        if ([obj2 isKindOfClass:[UIImageView class]])
                        {
                            
                            UIImageView *imageView2=(UIImageView *)obj2;
                            imageView2.hidden=YES;
                        }
                    }
                }
            }
        }
    }