Create Tap-Able "Links" in the Nsattributedstring of a Uilabel

Create tap-able links in the NSAttributedString of a UILabel?

In general, if we want to have a clickable link in text displayed by UILabel, we would need to resolve two independent tasks:

1. Changing the appearance of a portion of the text to look like a link
2. Detecting and handling touches on the link (opening an URL is a particular case)

The first one is easy. Starting from iOS 6 UILabel supports display of attributed strings. All you need to do is to create and configure an instance of NSMutableAttributedString:

NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:@"String with a link" attributes:nil];
NSRange linkRange = NSMakeRange(14, 4); // for the word "link" in the string above

NSDictionary *linkAttributes = @{ NSForegroundColorAttributeName : [UIColor colorWithRed:0.05 green:0.4 blue:0.65 alpha:1.0],
                                  NSUnderlineStyleAttributeName : @(NSUnderlineStyleSingle) };
[attributedString setAttributes:linkAttributes range:linkRange];

// Assign attributedText to UILabel
label.attributedText = attributedString;

That's it! The code above makes UILabel to display String with a link

Now we should detect touches on this link. The idea is to catch all taps within UILabel and figure out whether the location of the tap was close enough to the link. To catch touches we can add tap gesture recognizer to the label. Make sure to enable userInteraction for the label, it's turned off by default:

label.userInteractionEnabled = YES;
[label addGestureRecognizer:[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTapOnLabel:)]]; 

Now the most sophisticated stuff: finding out whether the tap was on where the link is displayed and not on any other portion of the label. If we had single-lined UILabel, this task could be solved relatively easy by hardcoding the area bounds where the link is displayed, but let's solve this problem more elegantly and for general case - multiline UILabel without preliminary knowledge about the link layout.

One of the approaches is to use capabilities of Text Kit API introduced in iOS 7:

// Create instances of NSLayoutManager, NSTextContainer and NSTextStorage
NSLayoutManager *layoutManager = [[NSLayoutManager alloc] init];
NSTextContainer *textContainer = [[NSTextContainer alloc] initWithSize:CGSizeZero];
NSTextStorage *textStorage = [[NSTextStorage alloc] initWithAttributedString:attributedString];

// Configure layoutManager and textStorage
[layoutManager addTextContainer:textContainer];
[textStorage addLayoutManager:layoutManager];

// Configure textContainer
textContainer.lineFragmentPadding = 0.0;
textContainer.lineBreakMode = label.lineBreakMode;
textContainer.maximumNumberOfLines = label.numberOfLines;

Save created and configured instances of NSLayoutManager, NSTextContainer and NSTextStorage in properties in your class (most likely UIViewController's descendant) - we'll need them in other methods.

Now, each time the label changes its frame, update textContainer's size:

- (void)viewDidLayoutSubviews
{
    [super viewDidLayoutSubviews];
    self.textContainer.size = self.label.bounds.size;
}

And finally, detect whether the tap was exactly on the link:

- (void)handleTapOnLabel:(UITapGestureRecognizer *)tapGesture
{
    CGPoint locationOfTouchInLabel = [tapGesture locationInView:tapGesture.view];
    CGSize labelSize = tapGesture.view.bounds.size;
    CGRect textBoundingBox = [self.layoutManager usedRectForTextContainer:self.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);
    NSInteger indexOfCharacter = [self.layoutManager characterIndexForPoint:locationOfTouchInTextContainer
                                                            inTextContainer:self.textContainer
                                   fractionOfDistanceBetweenInsertionPoints:nil];
    NSRange linkRange = NSMakeRange(14, 4); // it's better to save the range somewhere when it was originally used for marking link in attributed string
    if (NSLocationInRange(indexOfCharacter, linkRange)) {
        // Open an URL, or handle the tap on the link in any other way
        [[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"https://stackoverflow.com/"]];
    }
}

How can I make a clickable link in an NSAttributedString?

I found this really useful but I needed to do it in quite a few places so I've wrapped my approach up in a simple extension to NSMutableAttributedString:

Swift 3

extension NSMutableAttributedString {

    public func setAsLink(textToFind:String, linkURL:String) -> Bool {

        let foundRange = self.mutableString.range(of: textToFind)
        if foundRange.location != NSNotFound {
            self.addAttribute(.link, value: linkURL, range: foundRange)
            return true
        }
        return false
    }
}

Swift 2

import Foundation

extension NSMutableAttributedString {

   public func setAsLink(textToFind:String, linkURL:String) -> Bool {

       let foundRange = self.mutableString.rangeOfString(textToFind)
       if foundRange.location != NSNotFound {
           self.addAttribute(NSLinkAttributeName, value: linkURL, range: foundRange)
           return true
       }
       return false
   }
}

Example usage:

let attributedString = NSMutableAttributedString(string:"I love stackoverflow!")
let linkWasSet = attributedString.setAsLink("stackoverflow", linkURL: "http://stackoverflow.com")

if linkWasSet {
    // adjust more attributedString properties
}

Objective-C

I've just hit a requirement to do the same in a pure Objective-C project, so here's the Objective-C category.

@interface NSMutableAttributedString (SetAsLinkSupport)

- (BOOL)setAsLink:(NSString*)textToFind linkURL:(NSString*)linkURL;

@end


@implementation NSMutableAttributedString (SetAsLinkSupport)

- (BOOL)setAsLink:(NSString*)textToFind linkURL:(NSString*)linkURL {

     NSRange foundRange = [self.mutableString rangeOfString:textToFind];
     if (foundRange.location != NSNotFound) {
         [self addAttribute:NSLinkAttributeName value:linkURL range:foundRange];
         return YES;
     }
     return NO;
}

@end

Example usage:

NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:"I love stackoverflow!"];

BOOL linkWasSet = [attributedString setAsLink:@"stackoverflow" linkURL:@"http://stackoverflow.com"];

if (linkWasSet) {
    // adjust more attributedString properties
}

Make Sure that the NSTextField's Behavior attribute is set as Selectable.

Tappable Dynamic Links With UILabel

As @DonMag pointed out, in the comments of the question - I could in fact use a UITextView, and disabling scrolling, which fixed the original reason I was having, that made me turn to do it with a UILabel.

How to make tappable links in NSAttributedString

    definition.editable = false;
    definition.delegate = self;

Hope can help you.

How do I add a link to a UILabel in swift?

Two ways to do it.

1. Tap gesture - UITapGestureRecognizer

// considering you have a UILabel is added to your screen and you have formatted the label to look like a link.
let labelTap = UITapGestureRecognizer(target: self, action: #selector(self.linkLabelTapped(_:)))
self.linkLabel.isUserInteractionEnabled = true
self.linkLabel.addGestureRecognizer(labelTap)


@objc func linkLabelTapped(_ sender: UITapGestureRecognizer) {
    print("linkLabelTapped")
}

2. Don't use UILabel but UITextView with link recognition which gives you the formatting by default.

linkTextView.userInteractionEnabled = true
linkTextView.selectable = true
linkTextView.dataDetectorTypes = .Link
linkTextView.text = "https://www.google.com."

iOS - Swift how to make links clicked in UILabel

As Luke said UILabels dont support URL's. But you can create a button to look like a label. Get rid of the background (so it looks like text )and implement the the function to the button to open the webview. You can use attributed strings to edit the style of the text in the button.

You are going to want to look into using a custom class instead of the default uibutton class when you add the button to your UI.

you will need to:

1. init

    - (instancetype)initWithFrame:(CGRect)frame {
      self = [super initWithFrame:frame];
        if (self)
        {
            //call the method to configure the button
            [self configure];
        }
      return self;
    }
   

2. implement setTitle or setAttributedTitle if you are using an attributed string

    - (void) setTitle:(NSString *)title forState:(UIControlState)state
    {
           [super setTitle:title forState:state]
    }      
   

or

      - (void)setAttributedTitle:(NSAttributedString *)title forState:   (UIControlState)state{
            [super setAttributedTitle:title forState:state];
         }

3. configure the button

         -(void) configure{
             //configure the buttons label here 
             //you will want to set no background colour
          }

4. add the button to viewcontroller and change the class to the custom class you created.

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