[英]Change navigationBar bottom border to a dashed line in swift
我想將我的navigationBar更改為以虛線作為邊框,如下所示:
我在此線程中找到了關於如何更改NavigationBar邊框顏色的妙妙答案: 更改Swift導航條底部邊框的顏色特別是: https : //stackoverflow.com/a/46224261/436014
通過UIColor擴展:
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
}
}
我想知道是否有任何方法可以改編虛線。 我當時以為可以通過以交替的顏色繪制填充來完成此操作,但由於它是單個UIcolor的擴展,因此感到困惑
navigationController.navigationBar.shadowImage = UIColor.black.as1ptImage()
因此,類似以下內容顯然不起作用:
UIGraphicsBeginImageContext(CGSize(width: 1, height: 4))
UIGraphicsGetCurrentContext()?.fill(CGRect(x: 0, y: 0, width: 1, height: 1))
UIGraphicsGetCurrentContext()?.fill(CGRect(x: 1, y: 0, width: 3, height: 1))
我想知道是否有人知道如何解決這個問題
好的,我設法借助CALayer的API文檔找到了一個解決方案: https : //developer.apple.com/documentation/quartzcore/cashapelayer/1521921-linedashpattern
這個關於將CALayer轉換為UIImage的SO線程: iOS中來自CALayer的UIImage
整個過程是:
CALayer
CALayer
一個框架 UIImage
navigationBar.shadowImage
不錯的是,它可以適當地平鋪,因此CALayer / UIImage只需與您生成的虛線一樣寬即可。
extension UIImage {
class func imageWithLayer(layer: CALayer) -> UIImage {
UIGraphicsBeginImageContextWithOptions(layer.bounds.size, layer.isOpaque, 0.0)
layer.render(in: UIGraphicsGetCurrentContext()!)
guard let img = UIGraphicsGetImageFromCurrentImageContext() else { return UIImage() }
UIGraphicsEndImageContext()
return img
}
}
let layer = CALayer()
layer.frame = CGRect(x: 0, y: 0, width: 6, height: 1)
let shapeLayer = CAShapeLayer()
shapeLayer.strokeColor = UIColor.black.cgColor
shapeLayer.lineWidth = 1
shapeLayer.lineDashPattern = [4,2]
let path = CGMutablePath()
path.addLines(between: [CGPoint(x:1, y: 0), CGPoint(x: 6, y:0)])
shapeLayer.path = path
layer.addSublayer(shapeLayer)
navigationController.navigationBar.shadowImage = UIImage.imageWithLayer(layer: layer)
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