Figure out size of UILabel based on String in Swift

Question

I am trying to calculate the height of a UILabel based on different String lengths.

func calculateContentHeight() -> CGFloat{
    var maxLabelSize: CGSize         


        

Answer 1

@IBOutlet weak var constraintTxtV: NSLayoutConstraint!
func TextViewDynamicallyIncreaseSize() {
    let contentSize = self.txtVDetails.sizeThatFits(self.txtVDetails.bounds.size)
    let higntcons = contentSize.height
    constraintTxtV.constant = higntcons
}

Answer 2

This solution will help to calculate the height and width at runtime.

    let messageText = "Your Text String"
    let size = CGSize.init(width: 250, height: 1000)
    let options = NSStringDrawingOptions.usesFontLeading.union(.usesLineFragmentOrigin)
    let estimateFrame = NSString(string: messageText).boundingRect(with:  size, options: options, attributes: [NSAttributedString.Key.font: UIFont(name: "HelveticaNeue", size: 17)!], context: nil)

Here you can calculate the estimated height that your string would take and pass it to the UILabel frame.

estimateFrame.Width
estimateFrame.Height 

Answer 3

In Swift 5:

label.textRect(forBounds: label.bounds, limitedToNumberOfLines: 1)

btw, the value of limitedToNumberOfLines depends on your label's text lines you want.

Answer 4

Swift 5:

If you have UILabel and someway boundingRect isn't working for you (I faced this problem. It always returned 1 line height.) there is an extension to easily calculate label size.

extension UILabel {
    func getSize(constrainedWidth: CGFloat) -> CGSize {
        return systemLayoutSizeFitting(CGSize(width: constrainedWidth, height: UIView.layoutFittingCompressedSize.height), withHorizontalFittingPriority: .required, verticalFittingPriority: .fittingSizeLevel)
    }
}

You can use it like this:

let label = UILabel()
label.text = "My text\nIs\nAwesome"
let labelSize = label.getSize(constrainedWidth:200.0)

Works for me

Answer 5

Heres a simple solution thats working for me... similar to some of the others posted, but it doesn't not include the need for calling sizeToFit

Note this is written in Swift 5

let lbl = UILabel()
lbl.numberOfLines = 0
lbl.font = UIFont.systemFont(ofSize: 12) // make sure you set this correctly 
lbl.text = "My text that may or may not wrap lines..."

let width = 100.0 // the width of the view you are constraint to, keep in mind any applied margins here

let height = lbl.systemLayoutSizeFitting(CGSize(width: width, height: UIView.layoutFittingCompressedSize.height), withHorizontalFittingPriority: .required, verticalFittingPriority: .fittingSizeLevel).height

This handles line wrapping and such. Not the most elegant code, but it gets the job done.

Answer 6

extension String{

    func widthWithConstrainedHeight(_ height: CGFloat, font: UIFont) -> CGFloat {
        let constraintRect = CGSize(width: CGFloat.greatestFiniteMagnitude, height: height)

        let boundingBox = self.boundingRect(with: constraintRect, options: NSStringDrawingOptions.usesLineFragmentOrigin, attributes: [NSFontAttributeName: font], context: nil)

        return ceil(boundingBox.width)
    }

    func heightWithConstrainedWidth(_ width: CGFloat, font: UIFont) -> CGFloat? {
        let constraintRect = CGSize(width: width, height: CGFloat.greatestFiniteMagnitude)
        let boundingBox = self.boundingRect(with: constraintRect, options: NSStringDrawingOptions.usesLineFragmentOrigin, attributes: [NSFontAttributeName: font], context: nil)

        return ceil(boundingBox.height)
    }

}