iOS 导航栏底部的线

通过遍历导航栏上的控件找到底部的线 ， 控制闲的隐藏与显示

- (UIImageView*)findHairlineImageViewUnder:(UIView*)view {

if([viewisKindOfClass:UIImageView.class] && view.bounds.size.height<=1.0) {

return(UIImageView*)view;

}

for(UIView*subviewinview.subviews) {

UIImageView*imageView = [selffindHairlineImageViewUnder:subview];

if(imageView) {

returnimageView;

}

}

returnnil;

}

-(void)viewWillAppear:(BOOL)animated

{

[superviewWillAppear:animated];

_navline.hidden=YES;

}

//在页面消失的时候就让出现

- (void)viewWillDisappear:(BOOL)animated{

[superviewWillDisappear:animated];

_navline.hidden=NO;

}

- (void)viewDidLoad {

[superviewDidLoad];

_navline= [selffindHairlineImageViewUnder:self.navigationController.navigationBar];

}