ios - iOS 11 中带有大标题导航栏的自定义背景图片

Question

iOS 11大标题NavigationBar如何设置自定义背景图？我正在使用一个自定义子类，我已将其分配给 Storyboard 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。它以前适用于 iOS 10，如果我旋转 iPhone(并激活小 NavBar)，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出现“正常”导航栏时，背景图像才可见。在这种情况下，barTintColor 也被完全忽略。

Answer 1

我遇到了同样的问题，已解决

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!)

获取带有渐变颜色的图像

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
}