iOS开发大部分情况下会使用到导航栏，由于我司的app导航栏需要与下面紧挨着的窗口颜色一致，导航栏底部的横线就会影响这个美观。
去除方法之一：（推荐）
UIImageView *backgroundView = [self.navigationController.navigationBar valueForKey:@"_backgroundView"];
for(UIView *view in backgroundView.subviews) {
if(view.bounds.size.height <= 1.0f) {
[view removeFromSuperview];
}
}
去除方法之二（不推荐，太复杂）。
1）声明UIImageView变量,存储底部横线
@interface MyViewController {
UIImageView *navBarHairlineImageView;
}
2）在viewDidLoad中加入：
navBarHairlineImageView = [self findHairlineImageViewUnder:self.navigationController.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;
}
