Getting the range of links in attributed string - ios

Question

I would like to find the range of links in attributed text, so I could apply custom underline only to the relevant words.
At the moment, the underline is under all of the text.
I want it to be only under the links.
The code is a bit complex as the requested underline is super customised.
import UIKit
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let text = "random text <a href='http://www.google.com'>http://www.google.com </a> more random text"
let storage = NSTextStorage()
let layout = UnderlineLayout()
storage.addLayoutManager(layout)
let container = NSTextContainer()
layout.addTextContainer(container)
let textView = UITextView(frame: CGRect(x: 30, y: 380, width: 300, height: 200), textContainer: container)
textView.isUserInteractionEnabled = true
textView.isEditable = false
textView.textContainerInset = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0)
textView.attributedText = htmlStyleAttributeText(text: text)
textView.backgroundColor = UIColor.white
textView.textColor = UIColor.black
let underLineColor: UIColor = UIColor(red: 245/255, green: 190/255, blue: 166/255, alpha: 1)
let attributes = [NSAttributedString.Key.underlineStyle.rawValue: 0x15,
NSAttributedString.Key.underlineColor: underLineColor,
NSAttributedString.Key.font: UIFont.systemFont(ofSize: 25),
NSAttributedString.Key.baselineOffset:0] as! [NSAttributedString.Key : Any]
let rg = NSRange(location: 0, length: textView.attributedText!.string.count)
storage.addAttributes(attributes, range: rg)
view.addSubview(textView)
}
public func htmlStyleAttributeText(text: String) -> NSMutableAttributedString? {
if let htmlData = text.data(using: .utf8) {
let options: [NSAttributedString.DocumentReadingOptionKey: Any] = [NSAttributedString.DocumentReadingOptionKey.documentType: NSAttributedString.DocumentType.html, NSAttributedString.DocumentReadingOptionKey.characterEncoding: String.Encoding.utf8.rawValue]
let attributedString = try? NSMutableAttributedString(data: htmlData, options: options, documentAttributes: nil)
return attributedString
}
return nil
}
}
import UIKit
class UnderlineLayout: NSLayoutManager {
override func drawUnderline(forGlyphRange glyphRange: NSRange, underlineType underlineVal: NSUnderlineStyle, baselineOffset: CGFloat, lineFragmentRect lineRect: CGRect, lineFragmentGlyphRange lineGlyphRange: NSRange, containerOrigin: CGPoint) {
if let container = textContainer(forGlyphAt: glyphRange.location, effectiveRange: nil) {
let boundingRect = self.boundingRect(forGlyphRange: glyphRange, in: container)
let offsetRect = boundingRect.offsetBy(dx: containerOrigin.x, dy: containerOrigin.y)
let left = offsetRect.minX
let bottom = offsetRect.maxY
let width = offsetRect.width
let path = UIBezierPath()
path.lineWidth = 4
path.move(to: CGPoint(x: left, y: bottom))
path.addLine(to: CGPoint(x: left + width, y: bottom))
path.stroke()
}
}
}

Answer 1

With:
let attributedText = htmlStyleAttributeText(text: text)!
...
textView.attributedText = attributedText
Separate the attributes:
let underlinesAttributes: [NSAttributedString.Key: Any] = [.underlineStyle: 0x15,
.underlineColor: underLineColor]
let attributes: [NSAttributedString.Key: Any] = [.font: UIFont.systemFont(ofSize: 25),
.baselineOffset: 0]
Apply the "basic ones" to the whole text:
let wholeRange = NSRange(attributedText.string.startIndex..., in: attributedText.string)
storage.addAttributes(attributes, range: wholeRange)
We now enumerate looking for the links, and apply the effect for each one found:
attributedText.enumerateAttribute(.link, in: wholeRange, options: []) { (value, range, pointee) in
if value != nil {
storage.addAttributes(underlinesAttributes, range: range)
}
}