ios显示或隐藏导航栏的底线

 

 

根据产品需求要求把这个界面导航栏的底线去掉,下个控制器还需要有底线.

 

使用下面的代码实现

 

 

//在页面出现的时候就将黑线隐藏起来

-(void)viewWillAppear:(BOOL)animated

{

    [self.navigationController.navigationBar setBackgroundImage:[UIImage new] forBarMetrics:UIBarMetricsDefault];

    [self.navigationController.navigationBar setShadowImage:[UIImage new]];

    _navBarHairlineImageView.hidden = YES;

}

//在页面消失的时候就让navigationbar还原样式

-(void)viewWillDisappear:(BOOL)animated{

    

    [self.navigationController.navigationBar setBackgroundImage:nil forBarMetrics:UIBarMetricsDefault];

    [self.navigationController.navigationBar setShadowImage:nil];

    //再定义一个imageview来等同于这个黑线

    //UIImageView *navBarHairlineImageView;

    _navBarHairlineImageView = [self findHairlineImageViewUnder:self.navigationController.navigationBar];

 

}

//这个方法唯一的不好就是会影响导航栏的translucent(透明)属性

 

//方法2:找出黑线,再做处理:

//通过一个方法来找到这个黑线(findHairlineImageViewUnder):

- (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;

}

 

////同样的在界面出现时候开启隐藏

//-(void)viewWillAppear:(BOOL)animated

//{

//    _navBarHairlineImageView.hidden = YES;

//}

////在页面消失的时候就让出现

-(void)viewDidAppear:(BOOL)animated

{

    _navBarHairlineImageView.hidden = NO;

}