如何在 Swift 中为导航栏添加阴影并隐藏边框？

Question

我目前正在使用以下代码向导航栏添加阴影：

self.navigationController?.navigationBar.layer.shadowColor = UIColor.black.cgColor
self.navigationController?.navigationBar.layer.shadowOffset = CGSize(width: 0.0, height: 4.0)
self.navigationController?.navigationBar.layer.shadowRadius = 4.0
self.navigationController?.navigationBar.layer.shadowOpacity = 0.3
self.navigationController?.navigationBar.layer.masksToBounds = false

这会产生以下结果： 阴影显示正确，但是我不希望显示导航栏的 1px 黑色边框，我只希望导航栏有阴影。我知道将导航栏的阴影属性设置为空图像会删除边框，但这也会隐藏阴影。有没有办法实现无边框阴影？

Answer 1

添加这个扩展：

extension UIView {
fileprivate var hairlineImageView: UIImageView? {
    return hairlineImageView(in: self)
}

fileprivate func hairlineImageView(in view: UIView) -> UIImageView? {
    if let imageView = view as? UIImageView, imageView.bounds.height <= 1.0 {
        return imageView
    }

    for subview in view.subviews {
        if let imageView = self.hairlineImageView(in: subview) { return imageView }
    }
    return nil
  }
}  

在 viewWillAppear 中的导航栏阴影后添加此行：

navigationController?.navigationBar.hairlineImageView?.isHidden = true

如果您想看到这条线已消失，请评论导航栏阴影并将表格视图分隔符颜色设置为清除...

//navigationController?.navigationBar.layer.shadowColor = UIColor.black.cgColor
//navigationController?.navigationBar.layer.shadowOffset = CGSize(width: 0.0, height: 4.0)
//navigationController?.navigationBar.layer.shadowRadius = 4.0
//navigationController?.navigationBar.layer.shadowOpacity = 0.3
//navigationController?.navigationBar.layer.masksToBounds = false
    
navigationController?.navigationBar.hairlineImageView?.isHidden = true
tableView.separatorColor = .clear