这是个老问题了，奈何不知道是自己的项目原因还是Xcode版本更新，网上搜了好多都解决不掉，找了好久最后终于找到一个能解决的，之前项目太忙忘记记录转自何方，现在想起来整理，感谢原作者。
#import "RootViewController.h"
@interface RootViewController ()
@property (nonatomic, strong)UIImageView *contentLineImageView;
@end
@implementation RootViewController
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
_contentLineImageView.hidden = YES;
}
- (void)viewWillDisappear:(BOOL)animated {
[super viewWillDisappear:animated];
_contentLineImageView.hidden = NO;
}
// 消除导航栏下的线
- (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;
}
- (void)viewDidLoad {
[super viewDidLoad];
_contentLineImageView = [self findHairlineImageViewUnder:self.navigationController.navigationBar];
}
