Underline text in a UITextView

Question

How can I underline text in a UITextView. I understand that I would need to create a subclass of UITextView, but what would go under drawRect

Answer 1

Swift 5. As my UITextView if for inserting text, I created an extension function as bellow.

extension UITextView {

  func underlined() {
    let border = CALayer()
    let width = CGFloat(1.0)
    border.borderColor = UIColor.lightGray.cgColor
    border.frame = CGRect(x: 0, y: self.frame.size.height - 5, width:  self.frame.size.width, height: 1)
    border.borderWidth = width
    self.layer.addSublayer(border)
    self.layer.masksToBounds = true
    let style = NSMutableParagraphStyle()
    style.lineSpacing = 15
    let attributes = [NSAttributedString.Key.paragraphStyle : style, NSAttributedString.Key.foregroundColor : UIColor.darkGray, NSAttributedString.Key.font :  UIFont.systemFont(ofSize: 13)]
    self.attributedText = NSAttributedString(string: self.text, attributes: attributes)
  }

}

The border is drawling the line and the style is adding the spacing between the lines. Usage in your UIView custom layout:

override func layoutSubviews() {
    super.layoutSubviews()
    self.dateAndTimeInput.underlined()
  }

Image with the result