iOS 去除 导航栏的 自带 线条 （导航栏下面会有一条线 ）

1.    UIImageView*navBarHairlineImageView;2. - (UIImageView*)findHairlineImageViewUnder:(UIView*)view {        if([view isKindOfClass:UIImageView.class] && view.bounds.size.height<=1.0)    {        return (UIImageView*)view;    }    for(UIView*subview in view.subviews)    {        UIImageView*imageView = [self findHairlineImageViewUnder:subview];        if(imageView)        {            return imageView;        }    }    return nil;}3. -(void)viewWillAppear:(BOOL)animated{    [super viewWillAppear:animated];        navBarHairlineImageView.hidden=YES;}-(void)viewWillDisappear:(BOOL)animated{    navBarHairlineImageView.hidden=NO;    }4- (void)viewDidLoad {    [super viewDidLoad];        navBarHairlineImageView= [self findHairlineImageViewUnder:self.navigationController.navigationBar];

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</pre><pre name="code" class="objc">应该可以看得懂吧  写在不同的方法里面的。。不明白的可以来问我