Technical Q&A QA1487

Embedding Hyperlinks in NSTextField and NSTextView

Q: How do I embed a hyperlink inside an NSTextField or NSTextView?

A: You can embed a hyperlink using an NSAttributedString. The resultant attributed string will contain the url, style and color for display.

**Figure 1** An example illustration of an NSTextField with a hyperlink.

Extending NSAttributedString

An easy way to factor this in your application is to add a "category" to the NSAttributedString class. By adding an additional class method to this category, you allow other classes to benefit from this extended feature.

Listing 1 Adding a category to NSAttributedString.

@interface NSAttributedString (Hyperlink)

    +(id)hyperlinkFromString:(NSString*)inString withURL:(NSURL*)aURL;

@end

@implementation NSAttributedString (Hyperlink)

+(id)hyperlinkFromString:(NSString*)inString withURL:(NSURL*)aURL

    NSMutableAttributedString* attrString = [[NSMutableAttributedString alloc] initWithString: inString];

    NSRange range = NSMakeRange(0, [attrString length]);

    [attrString beginEditing];

    [attrString addAttribute:NSLinkAttributeName value:[aURL absoluteString] range:range];

    // make the text appear in blue

    [attrString addAttribute:NSForegroundColorAttributeName value:[NSColor blueColor] range:range];

    // next make the text appear with an underline

    [attrString addAttribute:

            NSUnderlineStyleAttributeName value:[NSNumber numberWithInt:NSSingleUnderlineStyle] range:range];

    [attrString endEditing];

    return [attrString autorelease];

@end

Hyperlink in an NSTextField

Listing 2 Creating a hyperlink attributed string inside an NSTextField.

-(void)setHyperlinkWithTextField:(NSTextField*)inTextField

    // both are needed, otherwise hyperlink won't accept mousedown

    [inTextField setAllowsEditingTextAttributes: YES];

    [inTextField setSelectable: YES];

    NSURL* url = [NSURL URLWithString:@"http://www.apple.com"];

    NSMutableAttributedString* string = [[NSMutableAttributedString alloc] init];

    [string appendAttributedString: [NSAttributedString hyperlinkFromString:@"Apple Computer" withURL:url]];

    // set the attributed string to the NSTextField

    [inTextField setAttributedStringValue: string];

    [string release];

As you can see, setHyperlinkWithTextField: can reside in your class, which can be called from your class's -awakeFromNib or NSDocument's -windowControllerDidLoadNib:, for example.

Hyperlink in an NSTextView

Listing 3 Creating a hyperlink attributed string inside an NSTextView.

-(void)setHyperlinkWithTextView:(NSTextView*)inTextView

    // create the attributed string

    NSMutableAttributedString *string = [[NSMutableAttributedString alloc] init];

    // create the url and use it for our attributed string

    NSURL* url = [NSURL URLWithString: @"http://www.apple.com"];

    [string appendAttributedString:[NSAttributedString hyperlinkFromString:@"Apple Computer" withURL:url]];

    // apply it to the NSTextView's text storage

    [[inTextView textStorage] setAttributedString: string];

    [string release];

Note that Listing 3 sets the attributed string a little differently for NSTextView. You must set the text using the NSTextStorage object. NSTextStorage is a subclass of NSAttributedString that is the backing store for an NSTextView object.

Document Revision History

Date	Notes
2012-01-05	Removed leaks in two code snippets.
2006-10-02	New document that shows how a Cocoa app can embed a hyperlink inside both NSTextField and NSTextView using NSAttributedString.