Resizing UILabel with HTML data

Question

I created a UILabel and synced its font size with a seekbar and loaded my html formatted text onto the UILabel. Unfortunately, the format gets removed if I change the font size of my UILabel using seekbar.

I used this approach, from garie, that was answered from another thread

private func getHtmlLabel(text: String) -> UILabel {
    let label = UILabel()
    label.numberOfLines = 0
    label.lineBreakMode = .byWordWrapping
    label.attributedString = stringFromHtml(string: text)
    return label
}

private func stringFromHtml(string: String) -> NSAttributedString? {
    do {
        let data = string.data(using: String.Encoding.utf8, allowLossyConversion: true)
        if let d = data {
            let str = try NSAttributedString(data: d,
                                             options: [NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType],
                                             documentAttributes: nil)
            return str
        }
    } catch {
    }
    return nil
}

Link: Swift: Display HTML data in a label or textView

Is there any approach I could use to retain the my html formatted text?

EDIT #1: This is how I resize my UILabel.

@IBOutlet weak var textLabel: UILabel!
@IBAction func resizeText(_ sender: UISlider) {
    textLabel.font = UIFont.systemFont(ofSize: CGFloat(sender.value) * 20.0)
}

The HTML data I'm passing onto my UILabel:

<html><body><b>hello world</b></body></html>

This is the formatted HTML data on UILabel:

After resizing the UILabel, it loses its format:

EDIT #2:

Tried Milan's answer but encountered an error. Unresolved identifier in NSAttributedStringKey

Here's my code:

import UIKit

class GalleryViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        textLabel.attributedText = stringFromHtml()
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }

    @IBOutlet weak var textLabel: UILabel!
    @IBAction func resizeText(_ sender: UISlider) {
        if let attributedText = textLabel.attributedText {
            let newAttributedText = NSMutableAttributedString(attributedString: attributedText)
            newAttributedText.setFontSize(newSize: CGFloat(sender.value) * 20.0)
            textLabel.attributedText = newAttributedText
        }
    }


    private func stringFromHtml() -> NSAttributedString? {
        do {
            let string = "<html><body><b>hello world</b></body></html>"
            let data = string.data(using: String.Encoding.utf8, allowLossyConversion: true)
            if let d = data {
                let str = try NSAttributedString(data: d,
                                                 options: [NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType],
                                                 documentAttributes: nil)
                return str
            }
        } catch {
        }
        return nil
    }
}

extension NSMutableAttributedString {
    func setFontSize(newSize: CGFloat) {
        beginEditing()
        self.enumerateAttribute(NSAttributedStringKey.font, in: NSRange(location: 0, length: self.length)) { (value, range, stop) in
            if let f = value as? UIFont {
                let newFont = f.withSize(newSize)
                removeAttribute(NSAttributedStringKey.font, range: range)
                addAttribute(NSAttributedStringKey.font, value: newFont, range: range)
            }
        }
        endEditing()
    }
}

Show how you do resize your text in label – Milan Nosáľ Feb 04 '18 at 10:41 — Milan Nosáľ, Feb 04 '18 at 10:41
Added code on resizing my UILabel font size. – Paolo Uriel N. Enriquez Feb 04 '18 at 11:55 — Paolo Uriel N. Enriquez, Feb 04 '18 at 11:55
try my answer.. haven't tested it, but we will see – Milan Nosáľ Feb 04 '18 at 12:15 — Milan Nosáľ, Feb 04 '18 at 12:15
or use a TextView set not to scroll – iOS Flow Jul 12 '18 at 01:28 — iOS Flow, Jul 12 '18 at 01:28

Milan Nosáľ · Accepted Answer · 2018-02-04T12:54:59.233

2

Setting the font directly messes up your attributed text. You will have to set font size on the attributedText:

@IBAction func resizeText(_ sender: UISlider) {
    if let attributedText = textLabel.attributedText {
        let newAttributedText = NSMutableAttributedString(attributedString: attributedText)
        newAttributedText.setFontSize(newSize: CGFloat(sender.value) * 20.0)
        textLabel.attributedText = newAttributedText
    }
}

For this to work you will need following extension on NSMutableAttributedString:

extension NSMutableAttributedString {
    func setFontSize(newSize: CGFloat) {
        beginEditing()
        self.enumerateAttribute(NSAttributedStringKey.font, in: NSRange(location: 0, length: self.length)) { (value, range, stop) in
            if let f = value as? UIFont {
                let newFont = f.withSize(newSize)
                removeAttribute(NSAttributedStringKey.font, range: range)
                addAttribute(NSAttributedStringKey.font, value: newFont, range: range)
            }
        }
        endEditing()
    }
}

edited Feb 04 '18 at 12:54

answered Feb 04 '18 at 12:15

Milan Nosáľ

19,169
4
55
90

.font in self.enumerateAttribute() says Type string has no member font. – Paolo Uriel N. Enriquez Feb 04 '18 at 12:52
@PaoloUrielN.Enriquez where did you put that extension? – Milan Nosáľ Feb 04 '18 at 12:54
Below my GalleryViewController class. – Paolo Uriel N. Enriquez Feb 04 '18 at 12:55
@PaoloUrielN.Enriquez weird.. try with the updated answer – Milan Nosáľ Feb 04 '18 at 12:55
It now shows unresolved identifier. Do I need an import for NSAttributedStringKey? Btw, I'm on Swift 3 – Paolo Uriel N. Enriquez Feb 04 '18 at 12:58
@PaoloUrielN.Enriquez Just the `UIKit`.. edit the answer and show there the whole code in that particular file – Milan Nosáľ Feb 04 '18 at 12:59
1

@PaoloUrielN.Enriquez based on the rest of the code I guess you are using an older swift version than I do, so just replace `NSAttributedStringKey.font` with `NSFontAttributeName` – Milan Nosáľ Feb 04 '18 at 13:08
Thank you sir Milan! I'm just new to iOS and apparently found out that it is harder to customize views and layouts here than Android. Good day! – Paolo Uriel N. Enriquez Feb 04 '18 at 13:11
@PaoloUrielN.Enriquez that depends.. it's a bit harder with attributedStrings, but if you just use `UIFont` with textColor, basic customization is pretty easy.. good luck anyway :) – Milan Nosáľ Feb 04 '18 at 13:13

score 0 · Answer 2 · answered Feb 04 '18 at 09:16

0

Try using UserDefaults to save the the NSAttributedString returning from second function:

1- Hold the attributed text in a variable

let attributedText = stringFromHtml(string: String)

2- Save it in UserDefaults

UserDefaults.standard.set(attributedText, forKey: "attributedText")

And for retrieving it you may use this format to safely unwrap the value:

if let text = UserDefaults.standard.object(forKey: "attributedText") as? NSAttributedString {
   label.attributedString = text
}

answered Feb 04 '18 at 09:16

rami

129
2
10

But I only wanted to resize my UILabel containing the formatted html text, NOT store it on a local database. – Paolo Uriel N. Enriquez Feb 04 '18 at 12:14
by using `myLabel.numberOfLines = 0` and `myLabel.lineBreakMode = .byWordWrapping` should resize the label by its contents , but don't set a height to the label – rami Feb 05 '18 at 12:59

Resizing UILabel with HTML data

2 Answers2