iOS隐藏导航条1px的底部横线

第二种方法：1）声明UIImageView变量,存储底部横线

@implementation MyViewController {

UIImageView *navBarHairlineImageView;

2）在viewDidLoad中加入：

navBarHairlineImageView = [self findHairlineImageViewUnder:navigationBar];

3）实现找出底部横线的函数

- (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;
}

4）最后在viewWillAppear，viewWillDisappear中处理

- (void)viewWillAppear:(BOOL)animated {
  [super viewWillAppear:animated];
  navBarHairlineImageView.hidden = YES;
}
- (void)viewWillDisappear:(BOOL)animated {
  [super viewWillDisappear:animated];
  navBarHairlineImageView.hidden = NO;
}