Many applications have text and in this text are web hyperlinks in rounded rect. When I click them UIWebView opens. What puzzles me is that they often have custom links, for example if words starts with # it is also clickable and the application responds by opening another view. How can I do that? Is it possible with UILabel or do I need UITextView or something else?
Create tap-able "links" in the NSAttributedString of a UILabel?
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37 Answers
Translating @samwize's Extension to Swift 4:
extension UITapGestureRecognizer {
func didTapAttributedTextInLabel(label: UILabel, inRange targetRange: NSRange) -> Bool {
guard let attrString = label.attributedText else {
return false
}
let layoutManager = NSLayoutManager()
let textContainer = NSTextContainer(size: .zero)
let textStorage = NSTextStorage(attributedString: attrString)
layoutManager.addTextContainer(textContainer)
textStorage.addLayoutManager(layoutManager)
textContainer.lineFragmentPadding = 0
textContainer.lineBreakMode = label.lineBreakMode
textContainer.maximumNumberOfLines = label.numberOfLines
let labelSize = label.bounds.size
textContainer.size = labelSize
let locationOfTouchInLabel = self.location(in: label)
let textBoundingBox = layoutManager.usedRect(for: textContainer)
let textContainerOffset = CGPoint(x: (labelSize.width - textBoundingBox.size.width) * 0.5 - textBoundingBox.origin.x, y: (labelSize.height - textBoundingBox.size.height) * 0.5 - textBoundingBox.origin.y)
let locationOfTouchInTextContainer = CGPoint(x: locationOfTouchInLabel.x - textContainerOffset.x, y: locationOfTouchInLabel.y - textContainerOffset.y)
let indexOfCharacter = layoutManager.characterIndex(for: locationOfTouchInTextContainer, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)
return NSLocationInRange(indexOfCharacter, targetRange)
}
}
To set up the recognizer (once you colored the text and stuff):
lblTermsOfUse.isUserInteractionEnabled = true
lblTermsOfUse.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(handleTapOnLabel(_:))))
...then the gesture recognizer:
@objc func handleTapOnLabel(_ recognizer: UITapGestureRecognizer) {
guard let text = lblAgreeToTerms.attributedText?.string else {
return
}
if let range = text.range(of: NSLocalizedString("_onboarding_terms", comment: "terms")),
recognizer.didTapAttributedTextInLabel(label: lblAgreeToTerms, inRange: NSRange(range, in: text)) {
goToTermsAndConditions()
} else if let range = text.range(of: NSLocalizedString("_onboarding_privacy", comment: "privacy")),
recognizer.didTapAttributedTextInLabel(label: lblAgreeToTerms, inRange: NSRange(range, in: text)) {
goToPrivacyPolicy()
}
}
UITextView supports data-detectors in OS3.0, whereas UILabel doesn't.
If you enable the data-detectors on the UITextView and your text contains URLs, phone numbers, etc. they will appear as links.
Most simple and reliable approach is to use UITextView as Kedar Paranjape recommended. Based on answer of Karl Nosworthy I finally came up with a simple UITextView subclass:
class LinkTextView: UITextView, UITextViewDelegate {
typealias Links = [String: String]
typealias OnLinkTap = (URL) -> Bool
var onLinkTap: OnLinkTap?
override init(frame: CGRect, textContainer: NSTextContainer?) {
super.init(frame: frame, textContainer: textContainer)
isEditable = false
isSelectable = true
isScrollEnabled = false //to have own size and behave like a label
delegate = self
}
required init?(coder: NSCoder) {
super.init(coder: coder)
}
func addLinks(_ links: Links) {
guard attributedText.length > 0 else {
return
}
let mText = NSMutableAttributedString(attributedString: attributedText)
for (linkText, urlString) in links {
if linkText.count > 0 {
let linkRange = mText.mutableString.range(of: linkText)
mText.addAttribute(.link, value: urlString, range: linkRange)
}
}
attributedText = mText
}
func textView(_ textView: UITextView, shouldInteractWith URL: URL, in characterRange: NSRange) -> Bool {
return onLinkTap?(URL) ?? true
}
// to disable text selection
func textViewDidChangeSelection(_ textView: UITextView) {
textView.selectedTextRange = nil
}
}
Usage is very simple:
let linkTextView = LinkTextView()
let tu = "Terms of Use"
let pp = "Privacy Policy"
linkTextView.text = "Please read the Some Company \(tu) and \(pp)"
linkTextView.addLinks([
tu: "https://some.com/tu",
pp: "https://some.com/pp"
])
linkTextView.onLinkTap = { url in
print("url: \(url)")
return true
}
Note that isScrollEnabled is false by default, as in most cases we need small label-like view with own size and without scrolling. Just set it true if you want a scrollable text view.
Also note that UITextView unlike UILabel has default text padding. To remove it and make layout same as in UILabel just add: linkTextView.textContainerInset = .zero
Implementing onLinkTap closure is not necessary, without it URLs is automatically open by UIApplication.
As Text selection is undesirable in most cases, but it can't be turned off it is dismissed in delegate method (Thanks to Carson Vo)
Some answers didn't work for me as expected. This is Swift solution that supports also textAlignment and multiline. No subclassing needed, just this UITapGestureRecognizer extension:
import UIKit
extension UITapGestureRecognizer {
func didTapAttributedString(_ string: String, in label: UILabel) -> Bool {
guard let text = label.text else {
return false
}
let range = (text as NSString).range(of: string)
return self.didTapAttributedText(label: label, inRange: range)
}
private func didTapAttributedText(label: UILabel, inRange targetRange: NSRange) -> Bool {
guard let attributedText = label.attributedText else {
assertionFailure("attributedText must be set")
return false
}
let textContainer = createTextContainer(for: label)
let layoutManager = NSLayoutManager()
layoutManager.addTextContainer(textContainer)
let textStorage = NSTextStorage(attributedString: attributedText)
if let font = label.font {
textStorage.addAttribute(NSAttributedString.Key.font, value: font, range: NSMakeRange(0, attributedText.length))
}
textStorage.addLayoutManager(layoutManager)
let locationOfTouchInLabel = location(in: label)
let textBoundingBox = layoutManager.usedRect(for: textContainer)
let alignmentOffset = aligmentOffset(for: label)
let xOffset = ((label.bounds.size.width - textBoundingBox.size.width) * alignmentOffset) - textBoundingBox.origin.x
let yOffset = ((label.bounds.size.height - textBoundingBox.size.height) * alignmentOffset) - textBoundingBox.origin.y
let locationOfTouchInTextContainer = CGPoint(x: locationOfTouchInLabel.x - xOffset, y: locationOfTouchInLabel.y - yOffset)
let characterTapped = layoutManager.characterIndex(for: locationOfTouchInTextContainer, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)
let lineTapped = Int(ceil(locationOfTouchInLabel.y / label.font.lineHeight)) - 1
let rightMostPointInLineTapped = CGPoint(x: label.bounds.size.width, y: label.font.lineHeight * CGFloat(lineTapped))
let charsInLineTapped = layoutManager.characterIndex(for: rightMostPointInLineTapped, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)
return characterTapped < charsInLineTapped ? targetRange.contains(characterTapped) : false
}
private func createTextContainer(for label: UILabel) -> NSTextContainer {
let textContainer = NSTextContainer(size: label.bounds.size)
textContainer.lineFragmentPadding = 0.0
textContainer.lineBreakMode = label.lineBreakMode
textContainer.maximumNumberOfLines = label.numberOfLines
return textContainer
}
private func aligmentOffset(for label: UILabel) -> CGFloat {
switch label.textAlignment {
case .left, .natural, .justified:
return 0.0
case .center:
return 0.5
case .right:
return 1.0
@unknown default:
return 0.0
}
}
}
Usage:
class ViewController: UIViewController {
@IBOutlet var label : UILabel!
let selectableString1 = "consectetur"
let selectableString2 = "cupidatat"
override func viewDidLoad() {
super.viewDidLoad()
let text = "Lorem ipsum dolor sit amet, \(selectableString1) adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat \(selectableString2) non proident, sunt in culpa qui officia deserunt mollit anim id est laborum."
label.attributedText = NSMutableAttributedString(attributedString: NSAttributedString(string: text))
let tapGesture = UITapGestureRecognizer(target: self, action: #selector(labelTapped))
label.addGestureRecognizer(tapGesture)
label.isUserInteractionEnabled = true
}
@objc func labelTapped(gesture: UITapGestureRecognizer) {
if gesture.didTapAttributedString(selectableString1, in: label) {
print("\(selectableString1) tapped")
} else if gesture.didTapAttributedString(selectableString2, in: label) {
print("\(selectableString2) tapped")
} else {
print("Text tapped")
}
}
}
Here’s a Swift implementation that is about as minimal as possible that also includes touch feedback. Caveats:
- You must set fonts in your NSAttributedStrings
- You can only use NSAttributedStrings!
- You must ensure your links cannot wrap (use non breaking spaces:
"\u{a0}") - You cannot change the lineBreakMode or numberOfLines after setting the text
- You create links by adding attributes with
.linkkeys
.
public class LinkLabel: UILabel {
private var storage: NSTextStorage?
private let textContainer = NSTextContainer()
private let layoutManager = NSLayoutManager()
private var selectedBackgroundView = UIView()
override init(frame: CGRect) {
super.init(frame: frame)
textContainer.lineFragmentPadding = 0
layoutManager.addTextContainer(textContainer)
textContainer.layoutManager = layoutManager
isUserInteractionEnabled = true
selectedBackgroundView.isHidden = true
selectedBackgroundView.backgroundColor = UIColor(white: 0, alpha: 0.3333)
selectedBackgroundView.layer.cornerRadius = 4
addSubview(selectedBackgroundView)
}
public required convenience init(coder: NSCoder) {
self.init(frame: .zero)
}
public override func layoutSubviews() {
super.layoutSubviews()
textContainer.size = frame.size
}
public override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
super.touchesBegan(touches, with: event)
setLink(for: touches)
}
public override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
super.touchesMoved(touches, with: event)
setLink(for: touches)
}
private func setLink(for touches: Set<UITouch>) {
if let pt = touches.first?.location(in: self), let (characterRange, _) = link(at: pt) {
let glyphRange = layoutManager.glyphRange(forCharacterRange: characterRange, actualCharacterRange: nil)
selectedBackgroundView.frame = layoutManager.boundingRect(forGlyphRange: glyphRange, in: textContainer).insetBy(dx: -3, dy: -3)
selectedBackgroundView.isHidden = false
} else {
selectedBackgroundView.isHidden = true
}
}
public override func touchesCancelled(_ touches: Set<UITouch>, with event: UIEvent?) {
super.touchesCancelled(touches, with: event)
selectedBackgroundView.isHidden = true
}
public override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
super.touchesEnded(touches, with: event)
selectedBackgroundView.isHidden = true
if let pt = touches.first?.location(in: self), let (_, url) = link(at: pt) {
UIApplication.shared.open(url)
}
}
private func link(at point: CGPoint) -> (NSRange, URL)? {
let touchedGlyph = layoutManager.glyphIndex(for: point, in: textContainer)
let touchedChar = layoutManager.characterIndexForGlyph(at: touchedGlyph)
var range = NSRange()
let attrs = attributedText!.attributes(at: touchedChar, effectiveRange: &range)
if let urlstr = attrs[.link] as? String {
return (range, URL(string: urlstr)!)
} else {
return nil
}
}
public override var attributedText: NSAttributedString? {
didSet {
textContainer.maximumNumberOfLines = numberOfLines
textContainer.lineBreakMode = lineBreakMode
if let txt = attributedText {
storage = NSTextStorage(attributedString: txt)
storage!.addLayoutManager(layoutManager)
layoutManager.textStorage = storage
textContainer.size = frame.size
}
}
}
}
I follow this version,
Swift 4:
import Foundation
class AELinkedClickableUILabel: UILabel {
typealias YourCompletion = () -> Void
var linkedRange: NSRange!
var completion: YourCompletion?
@objc func linkClicked(sender: UITapGestureRecognizer){
if let completionBlock = completion {
let textView = UITextView(frame: self.frame)
textView.text = self.text
textView.attributedText = self.attributedText
let index = textView.layoutManager.characterIndex(for: sender.location(in: self),
in: textView.textContainer,
fractionOfDistanceBetweenInsertionPoints: nil)
if linkedRange.lowerBound <= index && linkedRange.upperBound >= index {
completionBlock()
}
}
}
/**
* This method will be used to set an attributed text specifying the linked text with a
* handler when the link is clicked
*/
public func setLinkedTextWithHandler(text:String, link: String, handler: @escaping ()->()) -> Bool {
let attributextText = NSMutableAttributedString(string: text)
let foundRange = attributextText.mutableString.range(of: link)
if foundRange.location != NSNotFound {
self.linkedRange = foundRange
self.completion = handler
attributextText.addAttribute(NSAttributedStringKey.link, value: text, range: foundRange)
self.isUserInteractionEnabled = true
self.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(linkClicked(sender:))))
return true
}
return false
}
}
Call Example:
button.setLinkedTextWithHandler(text: "This website (stackoverflow.com) is awesome", link: "stackoverflow.com")
{
// show popup or open to link
}
I found a other solution:
I find a way to detect the link in a html text that you find from the internet you transform it into nsattributeString with :
func htmlAttributedString(fontSize: CGFloat = 17.0) -> NSAttributedString? {
let fontName = UIFont.systemFont(ofSize: fontSize).fontName
let string = self.appending(String(format: "<style>body{font-family: '%@'; font-size:%fpx;}</style>", fontName, fontSize))
guard let data = string.data(using: String.Encoding.utf16, allowLossyConversion: false) else { return nil }
guard let html = try? NSMutableAttributedString (
data: data,
options: [NSAttributedString.DocumentReadingOptionKey.documentType: NSAttributedString.DocumentType.html],
documentAttributes: nil) else { return nil }
return html
}
My method allows you to detect the hyperlink without having to specify them.
first you create an extension of the tapgesturerecognizer :
extension UITapGestureRecognizer { func didTapAttributedTextInLabel(label: UILabel, inRange targetRange: NSRange) -> Bool { guard let attrString = label.attributedText else { return false } let layoutManager = NSLayoutManager() let textContainer = NSTextContainer(size: .zero) let textStorage = NSTextStorage(attributedString: attrString) layoutManager.addTextContainer(textContainer) textStorage.addLayoutManager(layoutManager) textContainer.lineFragmentPadding = 0 textContainer.lineBreakMode = label.lineBreakMode textContainer.maximumNumberOfLines = label.numberOfLines let labelSize = label.bounds.size textContainer.size = labelSize let locationOfTouchInLabel = self.location(in: label) let textBoundingBox = layoutManager.usedRect(for: textContainer) let textContainerOffset = CGPoint(x: (labelSize.width - textBoundingBox.size.width) * 0.5 - textBoundingBox.origin.x, y: (labelSize.height - textBoundingBox.size.height) * 0.5 - textBoundingBox.origin.y) let locationOfTouchInTextContainer = CGPoint(x: locationOfTouchInLabel.x - textContainerOffset.x, y: locationOfTouchInLabel.y - textContainerOffset.y) let indexOfCharacter = layoutManager.characterIndex(for: locationOfTouchInTextContainer, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil) return NSLocationInRange(indexOfCharacter, targetRange) }}
then in you view controller you created a list of url and ranges to store all the links and the range that the attribute text contain:
var listurl : [String] = []
var listURLRange : [NSRange] = []
to find the URL and the URLRange you can use :
fun findLinksAndRange(attributeString : NSAttributeString){
notification.enumerateAttribute(NSAttributedStringKey.link , in: NSMakeRange(0, notification.length), options: [.longestEffectiveRangeNotRequired]) { value, range, isStop in
if let value = value {
print("\(value) found at \(range.location)")
let stringValue = "\(value)"
listurl.append(stringValue)
listURLRange.append(range)
}
}
westlandNotifcationLabel.addGestureRecognizer(UITapGestureRecognizer(target : self, action: #selector(handleTapOnLabel(_:))))
}
then you implementing the handle tap :
@objc func handleTapOnLabel(_ recognizer: UITapGestureRecognizer) {
for index in 0..<listURLRange.count{
if recognizer.didTapAttributedTextInLabel(label: westlandNotifcationLabel, inRange: listURLRange[index]) {
goToWebsite(url : listurl[index])
}
}
}
func goToWebsite(url : String){
if let websiteUrl = URL(string: url){
if #available(iOS 10, *) {
UIApplication.shared.open(websiteUrl, options: [:],
completionHandler: {
(success) in
print("Open \(websiteUrl): \(success)")
})
} else {
let success = UIApplication.shared.openURL(websiteUrl)
print("Open \(websiteUrl): \(success)")
}
}
}
and here we go!
I hope this solution help you like it help me.
For fully custom links, you'll need to use a UIWebView - you can intercept the calls out, so that you can go to some other part of your app instead when a link is pressed.
Here's a drop-in Objective-C category that enables clickable links in existing UILabel.attributedText strings, exploiting the existing NSLinkAttributeName attribute.
@interface UILabel (GSBClickableLinks) <UIGestureRecognizerDelegate>
@property BOOL enableLinks;
@end
#import <objc/runtime.h>
static const void *INDEX;
static const void *TAP;
@implementation UILabel (GSBClickableLinks)
- (void)setEnableLinks:(BOOL)enableLinks
{
UITapGestureRecognizer *tap = objc_getAssociatedObject(self, &TAP); // retreive tap
if (enableLinks && !tap) { // add a gestureRegonzier to the UILabel to detect taps
tap = [UITapGestureRecognizer.alloc initWithTarget:self action:@selector(openLink)];
tap.delegate = self;
[self addGestureRecognizer:tap];
objc_setAssociatedObject(self, &TAP, tap, OBJC_ASSOCIATION_RETAIN_NONATOMIC); // save tap
}
self.userInteractionEnabled = enableLinks; // note - when false UILAbel wont receive taps, hence disable links
}
- (BOOL)enableLinks
{
return (BOOL)objc_getAssociatedObject(self, &TAP); // ie tap != nil
}
// First check whether user tapped on a link within the attributedText of the label.
// If so, then the our label's gestureRecogizer will subsequently fire, and open the corresponding NSLinkAttributeName.
// If not, then the tap will get passed along, eg to the enclosing UITableViewCell...
// Note: save which character in the attributedText was clicked so that we dont have to redo everything again in openLink.
- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
{
if (gestureRecognizer != objc_getAssociatedObject(self, &TAP)) return YES; // dont block other gestures (eg swipe)
// Re-layout the attributedText to find out what was tapped
NSTextContainer *textContainer = [NSTextContainer.alloc initWithSize:self.frame.size];
textContainer.lineFragmentPadding = 0;
textContainer.maximumNumberOfLines = self.numberOfLines;
textContainer.lineBreakMode = self.lineBreakMode;
NSLayoutManager *layoutManager = NSLayoutManager.new;
[layoutManager addTextContainer:textContainer];
NSTextStorage *textStorage = [NSTextStorage.alloc initWithAttributedString:self.attributedText];
[textStorage addLayoutManager:layoutManager];
NSUInteger index = [layoutManager characterIndexForPoint:[gestureRecognizer locationInView:self]
inTextContainer:textContainer
fractionOfDistanceBetweenInsertionPoints:NULL];
objc_setAssociatedObject(self, &INDEX, @(index), OBJC_ASSOCIATION_RETAIN_NONATOMIC); // save index
return (BOOL)[self.attributedText attribute:NSLinkAttributeName atIndex:index effectiveRange:NULL]; // tapped on part of a link?
}
- (void)openLink
{
NSUInteger index = [objc_getAssociatedObject(self, &INDEX) unsignedIntegerValue]; // retrieve index
NSURL *url = [self.attributedText attribute:NSLinkAttributeName atIndex:index effectiveRange:NULL];
if (url && [UIApplication.sharedApplication canOpenURL:url]) [UIApplication.sharedApplication openURL:url];
}
@end
This would be a bit cleaner done via a UILabel subclass (ie none of the objc_getAssociatedObject mess), but if you are like me you prefer to avoid having to make unnecessary (3rd party) subclasses just to add some extra function to existing UIKit classes. Also, this has the beauty that it adds clickable-links to any existing UILabel, eg existing UITableViewCells!
I've tried to make it as minimally invasive as possible by using the existing NSLinkAttributeName attribute stuff already available in NSAttributedString. So its a simple as:
NSURL *myURL = [NSURL URLWithString:@"http://www.google.com"];
NSMutableAttributedString *myString = [NSMutableAttributedString.alloc initWithString:@"This string has a clickable link: "];
[myString appendAttributedString:[NSAttributedString.alloc initWithString:@"click here" attributes:@{NSLinkAttributeName:myURL}]];
...
myLabel.attributedText = myString;
myLabel.enableLinks = YES; // yes, that's all! :-)
Basically, it works by adding a UIGestureRecognizer to your UILabel. The hard work is done in gestureRecognizerShouldBegin:, which re-layouts the attributedText string to find out which character was tapped on. If this character was part of a NSLinkAttributeName then the gestureRecognizer will subsequently fire, retrieve the corresponding URL (from the NSLinkAttributeName value), and open the link per the usual [UIApplication.sharedApplication openURL:url] process.
Note - by doing all this in gestureRecognizerShouldBegin:, if you dont happen to tap on a link in the label, the event is passed along. So, for example, your UITableViewCell will capture taps on links, but otherwise behave normally (select cell, unselect, scroll, ...).
I've put this in a GitHub repository here. Adapted from Kai Burghardt's SO posting here.
Yes this is possible albeit very confusing to figure out at first. I will go a step further and show you how you can even click on any area in the text as well.
With this method you can have UI Label tha is:
- Multiline Friendly
- Autoshrink Friendly
- Clickable Friendly (yes, even individual characters)
- Swift 5
Step 1:
Make the UILabel have the properties for Line Break of 'Truncate Tail' and set a minimum font scale.
If you are unfamiliar with font scale just remember this rule:
minimumFontSize/defaultFontSize = fontscale
In my case I wanted 7.2 to be the minimum font size and my starting font size was 36. Therefore, 7.2 / 36 = 0.2
Step 2:
If you do not care about the labels being clickable and just wanted a working multiline label you are done!
HOWEVER, if you want the labels to be clickable read on...
Add this following extension I created
extension UILabel {
func setOptimalFontSize(maxFontSize:CGFloat,text:String){
let width = self.bounds.size.width
var font_size:CGFloat = maxFontSize //Set the maximum font size.
var stringSize = NSString(string: text).size(withAttributes: [.font : self.font.withSize(font_size)])
while(stringSize.width > width){
font_size = font_size - 1
stringSize = NSString(string: text).size(withAttributes: [.font : self.font.withSize(font_size)])
}
self.font = self.font.withSize(font_size)//Forcefully change font to match what it would be graphically.
}
}
It's used like this (just replace <Label> with your actual label name):
<Label>.setOptimalFontSize(maxFontSize: 36.0, text: formula)
This extension is needed because auto shrink does NOT change the 'font' property of the label after it auto-shrinks so you have to deduce it by calculating it the same way it does by using .size(withAttributes) function which simulates what it's size would be with that particular font.
This is necessary because the solution for detecting where to click on the label requires the exact font size to be known.
Step 3:
Add the following extension:
extension UITapGestureRecognizer {
func didTapAttributedTextInLabel(label: UILabel, inRange targetRange: NSRange) -> Bool {
// Create instances of NSLayoutManager, NSTextContainer and NSTextStorage
let layoutManager = NSLayoutManager()
let textContainer = NSTextContainer(size: CGSize.zero)
let mutableAttribString = NSMutableAttributedString(attributedString: label.attributedText!)
mutableAttribString.addAttributes([NSAttributedString.Key.font: label.font!], range: NSRange(location: 0, length: label.attributedText!.length))
let paragraphStyle = NSMutableParagraphStyle()
paragraphStyle.lineSpacing = 6
paragraphStyle.lineBreakMode = .byTruncatingTail
paragraphStyle.alignment = .center
mutableAttribString.addAttributes([.paragraphStyle: paragraphStyle], range: NSMakeRange(0, mutableAttribString.string.count))
let textStorage = NSTextStorage(attributedString: mutableAttribString)
// Configure textContainer
textContainer.lineFragmentPadding = 0.0
textContainer.lineBreakMode = label.lineBreakMode
textContainer.maximumNumberOfLines = label.numberOfLines
// Configure layoutManager and textStorage
layoutManager.addTextContainer(textContainer)
textStorage.addLayoutManager(layoutManager)
let labelSize = label.bounds.size
textContainer.size = labelSize
// Find the tapped character location and compare it to the specified range
let locationOfTouchInLabel = self.location(in: label)
let textBoundingBox = layoutManager.usedRect(for: textContainer)
//let textContainerOffset = CGPointMake((labelSize.width - textBoundingBox.size.width) * 0.5 - textBoundingBox.origin.x,
//(labelSize.height - textBoundingBox.size.height) * 0.5 - textBoundingBox.origin.y);
let textContainerOffset = CGPoint(x: (labelSize.width - textBoundingBox.size.width) * 0.5 - textBoundingBox.origin.x, y: (labelSize.height - textBoundingBox.size.height) * 0.5 - textBoundingBox.origin.y)
//let locationOfTouchInTextContainer = CGPointMake(locationOfTouchInLabel.x - textContainerOffset.x,
// locationOfTouchInLabel.y - textContainerOffset.y);
let locationOfTouchInTextContainer = CGPoint(x: locationOfTouchInLabel.x - textContainerOffset.x, y: locationOfTouchInLabel.y - textContainerOffset.y)
let indexOfCharacter = layoutManager.characterIndex(for: locationOfTouchInTextContainer, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)
print("IndexOfCharacter=",indexOfCharacter)
print("TargetRange=",targetRange)
return NSLocationInRange(indexOfCharacter, targetRange)
}
}
You will need to modify this extension for your particular multiline situation. In my case you will notice that I use a paragraph style.
let paragraphStyle = NSMutableParagraphStyle()
paragraphStyle.lineSpacing = 6
paragraphStyle.lineBreakMode = .byTruncatingTail
paragraphStyle.alignment = .center
mutableAttribString.addAttributes([.paragraphStyle: paragraphStyle], range: NSMakeRange(0, mutableAttribString.string.count))
Make sure to change this in the extension to what you are actually using for your line spacing so that everything calculates correctly.
Step 4:
Add the gestureRecognizer to the label in viewDidLoad or where you think is appropriate like so (just replace <Label> with your label name again:
<Label>.addGestureRecognizer(UITapGestureRecognizer(target:self, action: #selector(tapLabel(gesture:))))
Here is a simplified example of my tapLabel function (just replace <Label> with your UILabel name):
@IBAction func tapLabel(gesture: UITapGestureRecognizer) {
guard let text = <Label>.attributedText?.string else {
return
}
let click_range = text.range(of: "(α/β)")
if gesture.didTapAttributedTextInLabel(label: <Label>, inRange: NSRange(click_range!, in: text)) {
print("Tapped a/b")
}else {
print("Tapped none")
}
}
Just a note in my example, my string is BED = N * d * [ RBE + ( d / (α/β) ) ], so I was just getting the range of the α/β in this case. You could add "\n" to the string to add a newline and whatever text you wanted after and test this to find a string on the next line and it will still find it and detect the click correctly!
That's it! You are done. Enjoy a multiline clickable label.
This generic method works too !
func didTapAttributedTextInLabel(gesture: UITapGestureRecognizer, inRange targetRange: NSRange) -> Bool {
let layoutManager = NSLayoutManager()
let textContainer = NSTextContainer(size: CGSize.zero)
guard let strAttributedText = self.attributedText else {
return false
}
let textStorage = NSTextStorage(attributedString: strAttributedText)
// Configure layoutManager and textStorage
layoutManager.addTextContainer(textContainer)
textStorage.addLayoutManager(layoutManager)
// Configure textContainer
textContainer.lineFragmentPadding = Constants.lineFragmentPadding
textContainer.lineBreakMode = self.lineBreakMode
textContainer.maximumNumberOfLines = self.numberOfLines
let labelSize = self.bounds.size
textContainer.size = CGSize(width: labelSize.width, height: CGFloat.greatestFiniteMagnitude)
// Find the tapped character location and compare it to the specified range
let locationOfTouchInLabel = gesture.location(in: self)
let xCordLocationOfTouchInTextContainer = locationOfTouchInLabel.x
let yCordLocationOfTouchInTextContainer = locationOfTouchInLabel.y
let locOfTouch = CGPoint(x: xCordLocationOfTouchInTextContainer ,
y: yCordLocationOfTouchInTextContainer)
let indexOfCharacter = layoutManager.characterIndex(for: locOfTouch, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)
guard let strLabel = text else {
return false
}
let charCountOfLabel = strLabel.count
if indexOfCharacter < (charCountOfLabel - 1) {
return NSLocationInRange(indexOfCharacter, targetRange)
} else {
return false
}
}
And you can call the method with
let text = yourLabel.text
let termsRange = (text as NSString).range(of: fullString)
if yourLabel.didTapAttributedTextInLabel(gesture: UITapGestureRecognizer, inRange: termsRange) {
showCorrespondingViewController()
}
Here is my answer based on @Luca Davanzo's answer, override the touchesBegan event instead of a tap gesture:
import UIKit
public protocol TapableLabelDelegate: NSObjectProtocol {
func tapableLabel(_ label: TapableLabel, didTapUrl url: String, atRange range: NSRange)
}
public class TapableLabel: UILabel {
private var links: [String: NSRange] = [:]
private(set) var layoutManager = NSLayoutManager()
private(set) var textContainer = NSTextContainer(size: CGSize.zero)
private(set) var textStorage = NSTextStorage() {
didSet {
textStorage.addLayoutManager(layoutManager)
}
}
public weak var delegate: TapableLabelDelegate?
public override var attributedText: NSAttributedString? {
didSet {
if let attributedText = attributedText {
textStorage = NSTextStorage(attributedString: attributedText)
} else {
textStorage = NSTextStorage()
links = [:]
}
}
}
public override var lineBreakMode: NSLineBreakMode {
didSet {
textContainer.lineBreakMode = lineBreakMode
}
}
public override var numberOfLines: Int {
didSet {
textContainer.maximumNumberOfLines = numberOfLines
}
}
public override init(frame: CGRect) {
super.init(frame: frame)
setup()
}
public required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
setup()
}
public override func layoutSubviews() {
super.layoutSubviews()
textContainer.size = bounds.size
}
/// addLinks
///
/// - Parameters:
/// - text: text of link
/// - url: link url string
public func addLink(_ text: String, withURL url: String) {
guard let theText = attributedText?.string as? NSString else {
return
}
let range = theText.range(of: text)
guard range.location != NSNotFound else {
return
}
links[url] = range
}
private func setup() {
isUserInteractionEnabled = true
layoutManager.addTextContainer(textContainer)
textContainer.lineFragmentPadding = 0
textContainer.lineBreakMode = lineBreakMode
textContainer.maximumNumberOfLines = numberOfLines
}
public override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
guard let locationOfTouch = touches.first?.location(in: self) else {
return
}
textContainer.size = bounds.size
let indexOfCharacter = layoutManager.glyphIndex(for: locationOfTouch, in: textContainer)
for (urlString, range) in links {
if NSLocationInRange(indexOfCharacter, range), let url = URL(string: urlString) {
delegate?.tapableLabel(self, didTapUrl: urlString, atRange: range)
}
}
}}
Modified @timbroder code to handle multiple line correctly for swift4.2
extension UITapGestureRecognizer {
func didTapAttributedTextInLabel(label: UILabel, inRange targetRange: NSRange) -> Bool {
// Create instances of NSLayoutManager, NSTextContainer and NSTextStorage
let layoutManager = NSLayoutManager()
let textContainer = NSTextContainer(size: CGSize.zero)
let textStorage = NSTextStorage(attributedString: label.attributedText!)
// Configure layoutManager and textStorage
layoutManager.addTextContainer(textContainer)
textStorage.addLayoutManager(layoutManager)
// Configure textContainer
textContainer.lineFragmentPadding = 0.0
textContainer.lineBreakMode = label.lineBreakMode
textContainer.maximumNumberOfLines = label.numberOfLines
let labelSize = label.bounds.size
textContainer.size = labelSize
// Find the tapped character location and compare it to the specified range
let locationOfTouchInLabel = self.location(in: label)
let textBoundingBox = layoutManager.usedRect(for: textContainer)
let textContainerOffset = CGPoint(x: (labelSize.width - textBoundingBox.size.width) * 0.5 - textBoundingBox.origin.x,
y: (labelSize.height - textBoundingBox.size.height) * 0.5 - textBoundingBox.origin.y);
let locationOfTouchInTextContainer = CGPoint(x: (locationOfTouchInLabel.x - textContainerOffset.x),
y: 0 );
// Adjust for multiple lines of text
let lineModifier = Int(ceil(locationOfTouchInLabel.y / label.font.lineHeight)) - 1
let rightMostFirstLinePoint = CGPoint(x: labelSize.width, y: 0)
let charsPerLine = layoutManager.characterIndex(for: rightMostFirstLinePoint, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)
let indexOfCharacter = layoutManager.characterIndex(for: locationOfTouchInTextContainer, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)
let adjustedRange = indexOfCharacter + (lineModifier * charsPerLine)
var newTargetRange = targetRange
if lineModifier > 0 {
newTargetRange.location = targetRange.location+(lineModifier*Int(ceil(locationOfTouchInLabel.y)))
}
return NSLocationInRange(adjustedRange, newTargetRange)
}
}
UILabel Code
let tapAction = UITapGestureRecognizer(target: self, action: #selector(self.tapLabel(gesture:)))
let quote = "For full details please see our privacy policy and cookie policy."
let attributedString = NSMutableAttributedString(string: quote)
let string1: String = "privacy policy", string2: String = "cookie policy"
// privacy policy
let rangeString1 = quote.range(of: string1)!
let indexString1: Int = quote.distance(from: quote.startIndex, to: rangeString1.lowerBound)
attributedString.addAttributes(
[.font: <UIfont>,
.foregroundColor: <UI Color>,
.underlineStyle: 0, .underlineColor:UIColor.clear
], range: NSRange(location: indexString1, length: string1.count));
// cookie policy
let rangeString2 = quote.range(of: string2)!
let indexString2: Int = quote.distance(from: quote.startIndex, to: rangeString2.lowerBound )
attributedString.addAttributes(
[.font: <UIfont>,
.foregroundColor: <UI Color>,
.underlineStyle: 0, .underlineColor:UIColor.clear
], range: NSRange(location: indexString2, length: string2.count));
let label = UILabel()
label.frame = CGRect(x: 20, y: 200, width: 375, height: 100)
label.isUserInteractionEnabled = true
label.addGestureRecognizer(tapAction)
label.attributedText = attributedString
Code to recognise the Tap
@objc
func tapLabel(gesture: UITapGestureRecognizer) {
if gesture.didTapAttributedTextInLabel(label: <UILabel>, inRange: termsLabelRange {
print("Terms of service")
} else if gesture.didTapAttributedTextInLabel(label:<UILabel> inRange: privacyPolicyLabelRange) {
print("Privacy policy")
} else {
print("Tapped none")
}
}
We use the convenient solution from zekel with the UITapGestureRecognizer category.
This uses NSTextContainer, like many answers to this question do.
However, this returned wrong character indexes. Apparently because NSTextContainer was missing information about the font style, as indicated by these other posts:
After changing:
NSTextStorage *textStorage = [[NSTextStorage alloc] initWithAttributedString:label.attributedText];
To:
// Apply the font of the label to the attributed text:
NSMutableAttributedString *attributedText = [[NSMutableAttributedString alloc] initWithAttributedString:label.attributedText];
NSMutableParagraphStyle *paragraphStyle = NSMutableParagraphStyle.new;
paragraphStyle.alignment = self.label.textAlignment;
[attributedText addAttributes:@{NSFontAttributeName: label.font, NSParagraphStyleAttributeName: paragraphStyle}
range:NSMakeRange(0, label.attributedText.string.length)];
// Init with attributed text from label:
NSTextStorage *textStorage = [[NSTextStorage alloc] initWithAttributedString:attributedText];
The result was significantly better, the tap area was now correctly starting at the first character of our target string. But the last character returned still NO. We expected that this was related to the fact that our target string has attributes to set the font weight to UIFontWeightSemibold. While the above code improvement applies label.font on the entire string, which has a regular weight.
To solve this we improved the above code snippet even further, by iterating over all attributed ranges, in order to support multiple font styles in the text:
// According to https://stackoverflow.com/a/47358270/2439941 it's required to apply the paragraph style and font of the UILabel.
// However, the attributed string might contain font formatting as well, e.g. to emphasize a word in a different font style.
// Therefor copy all attributes:
NSMutableAttributedString *attributedText = [[NSMutableAttributedString alloc] initWithAttributedString:label.attributedText];
[label.attributedText enumerateAttributesInRange:NSMakeRange(0, label.attributedText.length)
options:0
usingBlock:^(NSDictionary<NSAttributedStringKey,id> * _Nonnull attrs, NSRange range, BOOL * _Nonnull stop) {
// Add each attribute:
[attributedText addAttributes:attrs
range:range];
// In case the attributes of this range do NOT contain a font specifier, apply the font from the UILabel:
if (![attrs objectForKey:NSFontAttributeName]) {
[attributedText addAttributes:@{ NSFontAttributeName : label.font }
range:range];
}
}];
// Init the storage with the font attributed text:
NSTextStorage *textStorage = [[NSTextStorage alloc] initWithAttributedString:attributedText];
Now the method returns YES for every character in the semi-bold string range, which is the expected result.
- (BOOL)didTapAttributedTextInLabel:(UILabel *)label inRange:(NSRange)targetRange{
NSLayoutManager *layoutManager = [NSLayoutManager new];
NSTextContainer *textContainer = [[NSTextContainer alloc] initWithSize:CGSizeZero];
NSTextStorage *textStorage = [[NSTextStorage alloc] initWithAttributedString:label.attributedText];
[layoutManager addTextContainer:textContainer];
[textStorage addLayoutManager:layoutManager];
textContainer.lineFragmentPadding = 0.0;
textContainer.lineBreakMode = label.lineBreakMode;
textContainer.maximumNumberOfLines = label.numberOfLines;
CGSize labelSize = label.bounds.size;
textContainer.size = labelSize;
CGPoint locationOfTouchInLabel = [self locationInView:label];
CGRect textBoundingBox = [layoutManager usedRectForTextContainer:textContainer];
CGPoint textContainerOffset = CGPointMake((labelSize.width - textBoundingBox.size.width) * 0.5 - textBoundingBox.origin.x,
(labelSize.height - textBoundingBox.size.height) * 0.5 - textBoundingBox.origin.y);
CGPoint locationOfTouchInTextContainer = CGPointMake(locationOfTouchInLabel.x - textContainerOffset.x,
locationOfTouchInLabel.y - textContainerOffset.y);
NSUInteger indexOfCharacter =[layoutManager characterIndexForPoint:locationOfTouchInTextContainer inTextContainer:textContainer fractionOfDistanceBetweenInsertionPoints:nil];
return NSLocationInRange(indexOfCharacter, targetRange);
}
This is a Xamarin.iOS c# implementation based on Kedar's answer.
MyClickableTextViewWithCustomUrlScheme implementation with ShouldInteractWithUrl override:
// Inspired from https://stackoverflow.com/a/44112932/15186
internal class MyClickableTextViewWithCustomUrlScheme : UITextView, IUITextViewDelegate
{
public MyClickableTextViewWithCustomUrlScheme()
{
Initialize();
}
public MyClickableTextViewWithCustomUrlScheme(Foundation.NSCoder coder) : base(coder)
{
Initialize();
}
public MyClickableTextViewWithCustomUrlScheme(Foundation.NSObjectFlag t) : base(t)
{
Initialize();
}
public MyClickableTextViewWithCustomUrlScheme(IntPtr handle) : base(handle)
{
Initialize();
}
public MyClickableTextViewWithCustomUrlScheme(CoreGraphics.CGRect frame) : base(frame)
{
Initialize();
}
public MyClickableTextViewWithCustomUrlScheme(CoreGraphics.CGRect frame, NSTextContainer textContainer) : base(frame, textContainer)
{
Initialize();
}
void Initialize()
{
Delegate = this;
}
[Export("textView:shouldInteractWithURL:inRange:")]
public new bool ShouldInteractWithUrl(UITextView textView, NSUrl URL, NSRange characterRange)
{
if (URL.Scheme.CompareTo(@"username") == 0)
{
// Launch the Activity
return false;
}
// The system will handle the URL
return base.ShouldInteractWithUrl(textView, URL, characterRange);
}
}
Converted objective-C code in c# becomes:
MyClickableTextViewWithCustomUrlScheme uiHabitTile = new MyClickableTextViewWithCustomUrlScheme();
uiHabitTile.Selectable = true;
uiHabitTile.ScrollEnabled = false;
uiHabitTile.Editable = false;
// https://stackoverflow.com/a/34014655/15186
string wholeTitle = @"This is an example by marcelofabri";
NSMutableAttributedString attributedString = new NSMutableAttributedString(wholeTitle);
attributedString.AddAttribute(UIStringAttributeKey.Link,
new NSString("username://marcelofabri"),
attributedString.Value.RangeOfString(@"marcelofabri")
);
NSMutableDictionary<NSString, NSObject> linkAttributes = new NSMutableDictionary<NSString, NSObject>();
linkAttributes[UIStringAttributeKey.ForegroundColor] = UIColor.Green;
linkAttributes[UIStringAttributeKey.UnderlineColor] = UIColor.LightGray;
linkAttributes[UIStringAttributeKey.UnderlineStyle] = new NSNumber((short)NSUnderlineStyle.PatternSolid);
uiHabitTile.AttributedText = attributedString;
Make sure to set Editable = false and Selectable = true to be able to click the link.
Also ScrollEnabled = true allows the textview to size its height correctly.
Swift 5.2
I've found several issues with multiline text labels in previous answers, so I give my final working solution.
It solves the issues with multilines and text alignment.
func didTapAttributedTextInLabel(label: UILabel, inRange targetRange: NSRange) -> Bool {
// Create instances of NSLayoutManager, NSTextContainer and NSTextStorage
let layoutManager = NSLayoutManager()
let textContainer = NSTextContainer(size: CGSize.zero)
let textStorage = NSTextStorage(attributedString: label.attributedText!)
// Configure layoutManager and textStorage
layoutManager.addTextContainer(textContainer)
textStorage.addLayoutManager(layoutManager)
// Configure textContainer
textContainer.lineFragmentPadding = 0.0
textContainer.lineBreakMode = label.lineBreakMode
textContainer.maximumNumberOfLines = label.numberOfLines
let labelSize = label.bounds.size
textContainer.size = labelSize
// Find the tapped character location and compare it to the specified range
let locationOfTouchInLabel = self.location(in: label)
let textBoundingBox = layoutManager.usedRect(for: textContainer)
let textAligmentOffset = aligmentOffset(for: label)
let textContainerOffset = CGPoint(x: (labelSize.width - textBoundingBox.size.width) * textAligmentOffset - textBoundingBox.origin.x,
y: (labelSize.height - textBoundingBox.size.height) * textAligmentOffset - textBoundingBox.origin.y)
let locationOfTouchInTextContainer = CGPoint(x: (locationOfTouchInLabel.x - textContainerOffset.x),
y: 0 )
// Adjust for multiple lines of text
let lineModifier = Int(floor(locationOfTouchInLabel.y / label.font.lineHeight)) - 1
let rightMostFirstLinePoint = CGPoint(x: labelSize.width,
y: 0)
let charsPerLine = layoutManager.characterIndex(for: rightMostFirstLinePoint, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)
let indexOfCharacter = layoutManager.characterIndex(for: locationOfTouchInTextContainer, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)
let adjustedRange = indexOfCharacter + (lineModifier * charsPerLine)
return NSLocationInRange(adjustedRange, targetRange)
}
private func aligmentOffset(for label: UILabel) -> CGFloat {
switch label.textAlignment {
case .left, .natural, .justified:
return 0.0
case .center:
return 0.5
case .right:
return 1.0
@unknown default:
return 0.0
}
}
Starting from iOS 15, SwiftUI comes with built-in support Markdown markup language so text in Markdown:
Text("You can [click this link](https://www.example.com) to visit the website.")
Or as a simplest example with using SwiftUI you can do it like this:
HStack() {
Text("Open the")
.foregroundColor(.black)
Link(destination: URL(string: "https://www.example.com/TOS.html")!) {
Text("link")
.foregroundColor(.blue)
.underline()
}
Text("in browser")
.foregroundColor(.black)
}
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