在iOS 11中使用大标题NavigationBar自定义背景图像 [英] custom background image with large titles NavigationBar in iOS 11

问题描述

如何在iOS 11中为大型标题NavigationBar设置自定义背景图像？我正在使用我已经分配给故事板中的navigationControllers的自定义子类。

How do you set a custom background image for the large title NavigationBar in iOS 11? I'm using a custom subclass which I've assigned to the navigationControllers in the storyboard.

这是我创建自定义导航栏的方式：

This is how I create my custom NavBar:

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）对大型游戏不起作用。之前它适用于iOS 10，如果我旋转iPhone（并激活小型NavBar）背景又回来了？

Strangely the setBackgroundImage(image, for: .default) doesn't work for the large titles. It worked before with iOS 10 and also if I rotate the iPhone (and activate the small NavBar) the background is back?

编辑：
backgroundImage 仍然呈现，但不知何故隐藏了。仅当您开始滚动并出现正常导航栏时，才会看到backgroundImage。在这种情况下， barTintColor 也完全被忽略。

The backgroundImage is still rendered but somehow hidden. Only if you start scrolling and the "normal" Navigation Bar appears, the backgroundImage is visible. Also the barTintColor is completely ignored in this case.

推荐答案

我有相同的问题，修复它

I had the same issue, fixed it by

删除setBackgroundImage并使用带模式图像的barTint颜色

Remove setBackgroundImage and use barTint color with pattern image

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
}

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