How to adjust a UILabel line spacing programmatically in Swift? - ios

Question

I have a multiline UILabel as shown here:
I achieved this using the following code:
label.lineBreakMode = .ByWordWrapping
label.numberOfLines = 2
I'm trying to "decrease" the line spacing between the 1st line and 2nd line, and I tried to use the following code:
let text = label.attributedText
let mas = NSMutableAttributedString(attributedString:text!)
mas.replaceCharactersInRange(NSMakeRange(0, mas.string.utf16.count),
withString: label.text!)
label.attributedText = mas
However, it does not seem to work.
Thanks

Answer 1

Programmatically with Swift 4
Using label extension
extension UILabel {
// Pass value for any one of both parameters and see result
func setLineSpacing(lineSpacing: CGFloat = 0.0, lineHeightMultiple: CGFloat = 0.0) {
guard let labelText = self.text else { return }
let paragraphStyle = NSMutableParagraphStyle()
paragraphStyle.lineSpacing = lineSpacing
paragraphStyle.lineHeightMultiple = lineHeightMultiple
let attributedString:NSMutableAttributedString
if let labelattributedText = self.attributedText {
attributedString = NSMutableAttributedString(attributedString: labelattributedText)
} else {
attributedString = NSMutableAttributedString(string: labelText)
}
// Line spacing attribute
attributedString.addAttribute(NSAttributedStringKey.paragraphStyle, value:paragraphStyle, range:NSMakeRange(0, attributedString.length))
self.attributedText = attributedString
}
}
Now call extension function
let label = UILabel()
let stringValue = "How\nto\nadjust\na\nUILabel\nline\nspacing\nprogrammatically\nin\nSwift"
// Pass value for any one argument - lineSpacing or lineHeightMultiple
label.setLineSpacing(lineSpacing: 2.0) . // try values 1.0 to 5.0
// or try lineHeightMultiple
//label.setLineSpacing(lineHeightMultiple = 2.0) // try values 0.5 to 2.0
Or using label instance (Just copy & execute this code to see result)
let label = UILabel()
let stringValue = "How\nto\nadjust\na\nUILabel\nline\nspacing\nprogrammatically\nin\nSwift"
let attrString = NSMutableAttributedString(string: stringValue)
var style = NSMutableParagraphStyle()
style.lineSpacing = 24 // change line spacing between paragraph like 36 or 48
style.minimumLineHeight = 20 // change line spacing between each line like 30 or 40
// Line spacing attribute
attrString.addAttribute(NSAttributedStringKey.paragraphStyle, value: style, range: NSRange(location: 0, length: stringValue.characters.count))
// Character spacing attribute
attrString.addAttribute(NSAttributedStringKey.kern, value: 2, range: NSMakeRange(0, attrString.length))
label.attributedText = attrString
Swift 3
let label = UILabel()
let stringValue = "How to\ncontrol\nthe\nline spacing\nin UILabel"
let attrString = NSMutableAttributedString(string: stringValue)
var style = NSMutableParagraphStyle()
style.lineSpacing = 24 // change line spacing between paragraph like 36 or 48
style.minimumLineHeight = 20 // change line spacing between each line like 30 or 40
attrString.addAttribute(NSParagraphStyleAttributeName, value: style, range: NSRange(location: 0, length: stringValue.characters.count))
label.attributedText = attrString
From Interface Builder:

Answer 2

You're on the right track with NSAttributedString. You need to set the line spacing of the paragraph style:
let paragraphStyle = NSMutableParagraphStyle()
paragraphStyle.lineSpacing = 30 // Whatever line spacing you want in points
attributedString.addAttribute(NSParagraphStyleAttributeName, value:paragraphStyle, range:NSMakeRange(0, attributedString.length))
label.attributedText = attributedString;

Answer 3

Do this in the storyboard.....

Answer 4

func updateLabel(with title: String) {
let paragraphStyle = NSMutableParagraphStyle()
paragraphStyle.lineHeightMultiple = 0.8
paragraphStyle.alignment = .center
let string = NSAttributedString(string: title, attributes: [.paragraphStyle: paragraphStyle])
label.attributedText = string
}