删除导航栏下的细线

Question

我想要达到的效果是：

我的应用程序的当前状态是：

这是我的视图控制器的设置。我在导航栏下面放了一个工具栏。然后，我将工具栏的委托设置为导航栏。我已经阅读了几篇关于此的帖子。提供的一个解决方案是：

navigationController?.navigationBar.shadowImage = UIImage();
navigationController?.navigationBar.setBackgroundImage(UIImage(), forBarMetrics: .Default)

但是，这会导致导航栏变白并失去效果。所以我从这篇文章（UISegmentedControl below UINavigationbar in iOS 7）得到了以下代码：

    @IBOutlet weak var toolbar: UIToolbar!
    var hairLine: UIView = UIView()
    override func viewDidLoad() {
        super.viewDidLoad()
        doneButton.enabled = false

        for parent in self.navigationController!.navigationBar.subviews {
            for childView in parent.subviews {
                if childView is UIImageView && childView.bounds.size.width == self.navigationController!.navigationBar.frame.size.width {
                    hairLine = childView
                    print(hairLine.frame)
                }
            }
        }
    }

    func removeHairLine(appearing: Bool) {
        var hairLineFrame = hairLine.frame
        if appearing {
            hairLineFrame.origin.y += toolbar.bounds.size.height
        } else {
            hairLineFrame.origin.y -= toolbar.bounds.size.height
        }
        hairLine.frame = hairLineFrame
        print(hairLine.frame)
    }

    override func viewWillAppear(animated: Bool) {
        removeHairLine(true)
    }

    override func viewWillDisappear(animated: Bool) {
        removeHairLine(true)
    }

但是，此代码会在视图完全加载之前删除细线但在加载视图时会再次显示。任何解决方案？

Answer 1

我在这个网站上找到了解决方案，但不记得究竟在哪里。

目标-C：

WebUserControl1.ascx.cs

夫特：

<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="WebUserControl1.ascx.cs" Inherits="WebApplication1.ControlUI.WebUserControl1" %>
<asp:DropDownList ID="DropDownList1" runat="server">
    <asp:ListItem>Test: 1</asp:ListItem>
    <asp:ListItem>Test: 2</asp:ListItem>
    <asp:ListItem>Test: 3</asp:ListItem>
    <asp:ListItem>Test: 4</asp:ListItem>
    <asp:ListItem>Test: 5</asp:ListItem>
</asp:DropDownList>

Answer 2

试试这个

    for parent in self.navigationController!.navigationBar.subviews {
 for childView in parent.subviews {
     if(childView is UIImageView) {
         childView.removeFromSuperview()
     }
 }
}

我希望这对你有所帮助。

Answer 3

你可以用这个

 self.navigationController?.navigationBar.subviews[0].subviews.filter({$0 is UIImageView})[0].removeFromSuperview()

Answer 4

我使用这行代码

UINavigationBar.appearance().shadowImage = UIImage()
UINavigationBar.appearance().setBackgroundImage(UIImage(named: "background"), for: .default)

Answer 5

我没有找到任何好的Swift 3解决方案所以我添加了这个，基于Ivan Bruel answer.他的解决方案是面向协议的，允许在任何视图控制器中隐藏细线只有一行代码而没有子类化

将此代码添加到您的视图模型中：

protocol HideableHairlineViewController {

  func hideHairline()
  func showHairline()
}

extension HideableHairlineViewController where Self: UIViewController {

  func hideHairline() {
    findHairline()?.isHidden = true
  }

  func showHairline() {
    findHairline()?.isHidden = false
  }

  private func findHairline() -> UIImageView? {
    return navigationController?.navigationBar.subviews
      .flatMap { $0.subviews }
      .flatMap { $0 as? UIImageView }
      .filter { $0.bounds.size.width == self.navigationController?.navigationBar.bounds.size.width }
      .filter { $0.bounds.size.height <= 2 }
      .first
  }

}

然后确保不需要细线的视图控制器符合HideableHairlineViewController协议并致电hideHairline()。

Answer 6

alexandr答案的迅捷4版本

步骤1：创建类型为UIImageView?的属性

private var navigationBarHairLine: UIImageView? 

步骤2：创建findHairlineImageViewUnderView函数

  

此功能过滤视图的子视图以查找高度小于或等于1pt的视图。

func findHairlineImageViewUnderView(view: UIView?) -> UIImageView? { 
    guard let view = view else { return nil } 
    if view.isKind(of: UIImageView.classForCoder()) && view.bounds.height <= 1 { 
        return view as? UIImageView 
    } 
    for subView in view.subviews { 
        if let imageView = findHairlineImageViewUnderView(view: subView) { 
            return imageView 
        } 
    } 
    return nil 
}

第3步：在ViewWillAppear中调用创建的函数，并传入navigationBar。它将返回发际线视图，然后将其设置为隐藏。

override func viewWillAppear(_ animated: Bool) { 
    super.viewWillAppear(animated) 
    navigationBarHairLine = findHairlineImageViewUnderView(view: navigationController?.navigationBar) 
    navigationBarHairLine?.isHidden = true 
} 

Answer 7

您可以继承UINavigationBar的子类，并在初始化程序中设置以下内容（Swift 5）：

shadowImage = UIImage()
setBackgroundImage(UIImage(), for: .default) // needed for iOS 10

例如：

class CustomNavigationBar: UINavigationBar {

    override init(frame: CGRect) {
        super.init(frame: frame)
        setupViews()
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        setupViews()
    }


    private func setupViews() {
        shadowImage = UIImage()
        setBackgroundImage(UIImage(), for: .default) // needed for iOS 10
    }

}