iOS 11 中带有大标题导航栏的自定义背景图片

Question

iOS11如何为大标题NavigationBar设置自定义背景图片？我正在使用自定义子类，我已将其分配给情节提要中的 navigationControllers。

这就是我创建自定义导航栏的方式：

class CustomNavigationController: UINavigationController {

    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
        self.navigationBar.tintColor = UIColor(red:1, green:1, blue:1, alpha:0.6)
        self.navigationBar.titleTextAttributes = [NSForegroundColorAttributeName: UIColor.white]
        if #available(iOS 11.0, *) {
            self.navigationBar.prefersLargeTitles = true
            self.navigationItem.largeTitleDisplayMode = .automatic
            self.navigationBar.largeTitleTextAttributes = [NSForegroundColorAttributeName: UIColor.white]
            self.navigationBar.barTintColor = UIColor.green
        }
        self.navigationBar.isTranslucent = false
        self.navigationBar.setBackgroundImage(#imageLiteral(resourceName: "navigationBarBackground"), for: .default)
        self.navigationBar.shadowImage = #imageLiteral(resourceName: "navigationBarShadow")
    }
}

奇怪的是，setBackgroundImage(image, for: .default) 不适用于大标题。它以前与 iOS 10 一起工作，如果我旋转 iPhone（并激活小导航栏）背景又回来了？

编辑： backgroundImage 仍然呈现但不知何故被隐藏了。只有当您开始滚动并且 "normal" 导航栏出现时，背景图像才可见。在这种情况下， barTintColor 也被完全忽略。

Answer 1

在 iOS 11 中，如果您使用大标题，则不再需要设置 BackgroundImage（删除其声明）。相反，您需要使用 BarTintColor。

class CustomNavigationController: UINavigationController {

    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
        self.navigationBar.tintColor = UIColor(red:1, green:1, blue:1, alpha:0.6)
        self.navigationBar.titleTextAttributes = [NSForegroundColorAttributeName: UIColor.white]
        if #available(iOS 11.0, *) {
            self.navigationBar.prefersLargeTitles = true
            self.navigationItem.largeTitleDisplayMode = .automatic
            self.navigationBar.largeTitleTextAttributes = [NSForegroundColorAttributeName: UIColor.white]
            self.navigationBar.barTintColor = UIColor(red:1, green:1, blue:1, alpha:1)
        }
        else {
            self.navigationBar.setBackgroundImage(#imageLiteral(resourceName: "navigationBarBackground"), for: .default)                
        }
        self.navigationBar.shadowImage = #imageLiteral(resourceName: "navigationBarShadow")
        self.navigationBar.isTranslucent = false
    }
}

Answer 2

我遇到了同样的问题，已由

修复

删除 setBackgroundImage 并使用带有图案图像的 barTint 颜色

let bgimage = imageWithGradient(startColor: UIColor.red, endColor: UIColor.yellow, size: CGSize(width: UIScreen.main.bounds.size.width, height: 1))
self.navigationBar.barTintColor = UIColor(patternImage: bgimage!)

获取具有渐变颜色的图像

func imageWithGradient(startColor:UIColor, endColor:UIColor, size:CGSize, horizontally:Bool = true) -> UIImage? {

    let gradientLayer = CAGradientLayer()
    gradientLayer.frame = CGRect(x: 0, y: 0, width: size.width, height: size.height)
    gradientLayer.colors = [startColor.cgColor, endColor.cgColor]
    if horizontally {
        gradientLayer.startPoint = CGPoint(x: 0.0, y: 0.5)
        gradientLayer.endPoint = CGPoint(x: 1.0, y: 0.5)
    } else {
        gradientLayer.startPoint = CGPoint(x: 0.5, y: 0.0)
        gradientLayer.endPoint = CGPoint(x: 0.5, y: 1.0)
    }

    UIGraphicsBeginImageContext(gradientLayer.bounds.size)
    gradientLayer.render(in: UIGraphicsGetCurrentContext()!)
    let image = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    return image
}

Answer 3

在 Xamarin 中它会是这样的：

this.NavigationBar.BackgroundColor = UIColor.Clear;

      var gradientLayer = new CAGradientLayer
      {
        Frame = new CGRect(0, 0, UIApplication.SharedApplication.StatusBarFrame.Width,
              UIApplication.SharedApplication.StatusBarFrame.Height + this.NavigationBar.Frame.Height),
        Colors = new CGColor[]
              {Constants.Defaults.Navigation.RealBlueColor.ToCGColor(), Constants.Defaults.Navigation.RealBlueColor.ToCGColor()}
      };

      UIGraphics.BeginImageContext(gradientLayer.Bounds.Size);
      gradientLayer.RenderInContext((UIGraphics.GetCurrentContext()));
      UIImage image = UIGraphics.GetImageFromCurrentImageContext();
      UIGraphics.EndImageContext();

      this.View.Layer.InsertSublayer(gradientLayer, 0);
      this.NavigationBar.BarTintColor = UIColor.FromPatternImage(image);

this.View.Layer.Insert可选。当我 "curling" 在 NavigationBar

上上下移动图像时我需要它

Answer 4

试试这个代码 (Swift 4.0):

在viewDidLoad()中

self.navigationController?.navigationBar.titleTextAttributes = [NSAttributedStringKey.foregroundColor: UIColor.black]
if #available(iOS 11.0, *) {
    self.navigationController?.navigationBar.prefersLargeTitles = true
    self.navigationItem.largeTitleDisplayMode = .automatic
    self.navigationController?.navigationBar.largeTitleTextAttributes = [NSAttributedStringKey.foregroundColor: UIColor.black]
} else {
    //iOS <11.0
}
self.title = "Title"
self.navigationController?.navigationBar.barTintColor = UIColor(patternImage: #imageLiteral(resourceName: "nav_bg"))
self.navigationController?.navigationBar.isTranslucent = false

Answer 5

借用 oldrinmendez 的回答 - 该解决方案非常适合水平渐变。

对于垂直渐变，我能够通过在 scrollViewDidScroll 中再次调用它来使用 oldrinmendez 的答案中的相同函数。这会在用户滚动时不断调整渐变图像的高度。

从 oldrinmendez 的函数开始：

func imageWithGradient(startColor:UIColor, endColor:UIColor, size:CGSize, horizontally:Bool) -> UIImage? {

        let gradientLayer = CAGradientLayer()
        gradientLayer.frame = CGRect(x: 0, y: 0, width: size.width, height: size.height)
        gradientLayer.colors = [startColor.cgColor, endColor.cgColor]
        if horizontally {
            gradientLayer.startPoint = CGPoint(x: 0.0, y: 0.5)
            gradientLayer.endPoint = CGPoint(x: 1.0, y: 0.5)
        } else {
            gradientLayer.startPoint = CGPoint(x: 0.5, y: 0)
            gradientLayer.endPoint = CGPoint(x: 0.5, y: 1)
        }

        UIGraphicsBeginImageContext(gradientLayer.bounds.size)
        gradientLayer.render(in: UIGraphicsGetCurrentContext()!)
        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return image
    }

创建一个更新函数以使用您想要的选项调用它：

func updateImageWithGradient() {

        let navBarHeight  = self.navigationController?.navigationBar.frame.size.height
        let statusBarHeight = UIApplication.shared.statusBarFrame.height
        let heightAdjustment: CGFloat = 2

        let gradientHeight = navBarHeight! + statusBarHeight + heightAdjustment

        let bgimage = imageWithGradient(startColor: UIColor.red, endColor: UIColor.orange, size: CGSize(width: UIScreen.main.bounds.size.width, height: gradientHeight), horizontally: false)
        navigationController?.navigationBar.barTintColor = UIColor(patternImage: bgimage!)
    }

最后给 scrollViewDidScroll & ViewDidApper 添加更新函数: 使用 ViewDidAppear 返回正确的导航栏高度

override func viewDidAppear(_ animated: Bool) {
        updateImageWithGradient()
    }

override func scrollViewDidScroll(_ scrollView: UIScrollView) {
     DispatchQueue.main.async {
        updateImageWithGradient()
       }
    }

Answer 6

更改 barTint 对我不起作用，所以我更改了 navigationBar 中的图层

 navigationBar.layer.backgroundColor = UIColor(patternImage:
        UIImage(named: "BG-Roof1")!.resizableImage(withCapInsets:
            UIEdgeInsets(top: 0, left: 0, bottom: 10, right: 0), resizingMode: .stretch)).cgColor

Answer 7

终于找到解决办法了！

编辑：适用于 iOS 13 及更高版本

你可以在视图出现之前使用它，例如：在 viewDidLoad() 方法中：

    override func viewDidLoad()
    {
        super.viewDidLoad()

        let largeTitleAppearance = UINavigationBarAppearance() 

        largeTitleAppearance.configureWithOpaqueBackground()
        largeTitleAppearance.backgroundImage = UIImage(named: "BackgroundImage.png")

        self.navigationBar.standardAppearance = largeTitleAppearance
        self.navigationBar.scrollEdgeAppearance = largeTitleAppearance
    }

您只需要：

创建 UINavigationBarAppearance 实例：
```
let largeTitleAppearance = UINavigationBarAppearance() 
```
Apple 文档：

UINavigationBarAppearance - An object for customizing the appearance of a navigation bar.

配置一下：
```
largeTitleAppearance.configureWithOpaqueBackground()
```
"Opaque"这里是因为我们要设置彩色图像（但实际上无所谓，你设置什么配置）

设置背景图片：

largeTitleAppearance.backgroundImage = UIImage(named: "BackgroundImage.png") // Set here image that you need

将我们的 largeTitleAppearance 对象分配给 standardAppearance 和 scrollEdgeAppearance 导航栏字段：
```
self.navigationBar.standardAppearance = largeTitleAppearance // For large-navigationBar condition when it is collapsed
self.navigationBar.scrollEdgeAppearance = largeTitleAppearance // For large-navigationBar condition when it is expanded
```
Apple 文档：

.standardAppearance - The appearance settings for a standard-height navigation bar.

.scrollEdgeAppearance - The appearance settings to use when the edge of any scrollable content reaches the matching edge of the navigation bar.

这对我有帮助：https://sarunw.com/posts/uinavigationbar-changes-in-ios13/#going-back-to-old-style

iOS 11 中带有大标题导航栏的自定义背景图片

custom background image with large titles NavigationBar in iOS 11

uinavigationbar

ios

swift

ios11