选项1：在单个导航栏上

Question

适用于

import UIKit

class ViewController: UIViewController {

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

    self.navigationController?.navigationBar.setBackgroundImage(UIImage(), forBarMetrics: .Default)
    self.navigationController?.navigationBar.shadowImage = UIColor.redColor().as1ptImage()


}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}


}

extension UIColor {
    func as1ptImage() -> UIImage {
        UIGraphicsBeginImageContext(CGSizeMake(1, 1))
        let ctx = UIGraphicsGetCurrentContext()
        self.setFill()
        CGContextFillRect(ctx, CGRect(x: 0, y: 0, width: 1, height: 1))
        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return image
    }
}

但是当我添加一个UITableView它没有出现在它上面时，当我添加一个UISearchView时，它会出现但是会删除导航栏。

任何人都知道如何解决这个问题？

Answer 1

您必须调整导航栏的shadowImage属性。

试试这个。我在UIColor上创建了一个类别作为帮助，但你可以按自己喜欢的方式进行重构。

extension UIColor {
    func as1ptImage() -> UIImage {
        UIGraphicsBeginImageContext(CGSizeMake(1, 1))
        let ctx = UIGraphicsGetCurrentContext()
        self.setFill()
        CGContextFillRect(ctx, CGRect(x: 0, y: 0, width: 1, height: 1))
        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return image
    }
}

选项1：在单个导航栏上

然后在你的视图控制器中（将UIColor更改为你喜欢的）：

// We can use a 1px image with the color we want for the shadow image
self.navigationController?.navigationBar.shadowImage = UIColor.redColor().as1ptImage()

// We need to replace the navigation bar's background image as well 
// in order to make the shadowImage appear. We use the same 1px color tecnique
self.navigationController?.navigationBar.setBackgroundImage(UIColor.yellowColor‌().as1ptImage(), forBarMetrics: .Default)

选项2：在所有导航栏上使用外观代理

不是在每个导航栏上设置背景图像和阴影图像，而是可以依赖UIAppearance代理。您可以尝试将这些行添加到AppDelegate，而不是在viewDidLoad中添加先前的行。

// We can use a 1px image with the color we want for the shadow image
UINavigationBar.appearance().shadowImage = UIColor.redColor().as1ptImage()

// We need to replace the navigation bar's background image as well 
// in order to make the shadowImage appear. We use the same 1px color technique
UINavigationBar.appearance().setBackgroundImage(UIColor.yellowColor().as1ptImage(), forBarMetrics: .Default)

Answer 2

来自@ TheoF，@ Alessandro和@Pavel的精彩贡献。

这是我为...做的事情。

Swift 4

extension UIColor {

    /// Converts this `UIColor` instance to a 1x1 `UIImage` instance and returns it.
    ///
    /// - Returns: `self` as a 1x1 `UIImage`.
    func as1ptImage() -> UIImage {
        UIGraphicsBeginImageContext(CGSize(width: 1, height: 1))
        setFill()
        UIGraphicsGetCurrentContext()?.fill(CGRect(x: 0, y: 0, width: 1, height: 1))
        let image = UIGraphicsGetImageFromCurrentImageContext() ?? UIImage()
        UIGraphicsEndImageContext()
        return image
    }
}

在viewDidLoad()中使用它：

/* In this example, I have a ViewController embedded in a NavigationController in IB. */

// Remove the background color.
navigationController?.navigationBar.setBackgroundImage(UIColor.clear.as1ptImage(), for: .default)

// Set the shadow color.
navigationController?.navigationBar.shadowImage = UIColor.gray.as1ptImage()

Answer 3

Swift 3.0 只需更改此行：

CGContextFillRect(ctx, CGRect(x: 0, y: 0, width: 1, height: 1))

到此：

ctx?.fill(CGRect(x: 0, y: 0, width: 1, height: 1))

Answer 4

将@ alessandro-orru的答案放在一个扩展名中

extension UINavigationController {

    func setNavigationBarBorderColor(_ color:UIColor) {
        self.navigationBar.shadowImage = color.as1ptImage()
    }
}

extension UIColor {

    /// Converts this `UIColor` instance to a 1x1 `UIImage` instance and returns it.
    ///
    /// - Returns: `self` as a 1x1 `UIImage`.
    func as1ptImage() -> UIImage {
        UIGraphicsBeginImageContext(CGSize(width: 1, height: 1))
        setFill()
        UIGraphicsGetCurrentContext()?.fill(CGRect(x: 0, y: 0, width: 1, height: 1))
        let image = UIGraphicsGetImageFromCurrentImageContext() ?? UIImage()
        UIGraphicsEndImageContext()
        return image
    }
}

然后在您的视图控制器中只需添加：

self.navigationController?.setNavigationBarBorderColor(UIColor.red)

Answer 5

从iOS 13开始，您可以将UINavigationBarAppearance()类与shadowColor属性一起使用：

if #available(iOS 13.0, *) {
  let style = UINavigationBarAppearance()
  style.shadowColor = UIColor.clear // Effectively removes the border
  navigationController?.navigationBar.standardAppearance = style

  // Optional info for follow-ups:
  // The above will override other navigation bar properties so you may have to assign them here, for example:
  //style.buttonAppearance.normal.titleTextAttributes = [.font: UIFont(name: "YourFontName", size: 17)!]
  //style.backgroundColor = UIColor.orange
  //style.titleTextAttributes = [NSAttributedString.Key.foregroundColor: UIColor.white,
                               NSAttributedString.Key.font: UIFont(name: "AnotherFontName", size: 20.0)!]
} else {
  // Fallback on earlier versions
}

Answer 6

Swift 4.0-5.2解决方案

这是一个小扩展名，用于更改导航条底部的高度和颜色

extension UINavigationController
{
    func addCustomBottomLine(color:UIColor,height:Double)
    {
        //Hiding Default Line and Shadow
        navigationBar.setValue(true, forKey: "hidesShadow")

        //Creating New line
        let lineView = UIView(frame: CGRect(x: 0, y: 0, width:0, height: height))
        lineView.backgroundColor = color
        navigationBar.addSubview(lineView)

        lineView.translatesAutoresizingMaskIntoConstraints = false
        lineView.widthAnchor.constraint(equalTo: navigationBar.widthAnchor).isActive = true
        lineView.heightAnchor.constraint(equalToConstant: CGFloat(height)).isActive = true
        lineView.centerXAnchor.constraint(equalTo: navigationBar.centerXAnchor).isActive = true
        lineView.topAnchor.constraint(equalTo: navigationBar.bottomAnchor).isActive = true
    }
}

添加此扩展名后，您可以在任何UiNavController上调用此方法（例如，从ViewController viewDidLoad()）

self.navigationController?.addCustomBottomLine(color: UIColor.black, height: 20)

Answer 7

这几天有一个更好的选择：

UINavigationBar.appearance().shadowImage = UIImage()

Answer 8

对于iOS 13及更高版本

Stream

更改导航栏底部边框颜色Swift

8 个答案:

选项1：在单个导航栏上

选项2：在所有导航栏上使用外观代理