ContextLabel

A simple to use drop in replacement for UILabel written in Swift that provides automatic detection of links such as URLs, twitter style usernames and hashtags.

How to use it in your project

ContextLabel doesn't have any special dependencies so just include the files ContextLabel.swift in your project. Then use the ContextLabel class in replacement for UILabel.

Text colors

ContextLabel supports different colors for URLs, twitter style usernames and hashtags. By default the link text colors are set to userHandle RGB(71,90,109), hashtag RGB(151, 154, 158) and url/text links RGB(45, 113, 178).

To set your own text colors, return the desired UIColor within the closure value of foregroundColor:

contextLabel.foregroundColor = { (linkResult) in
		switch linkResult.detectionType {
    case .userHandle:
        return UIColor(red: 71.0/255.0, green: 90.0/255.0, blue: 109.0/255.0, alpha: 1.0)
    case .hashtag:
        return UIColor(red: 151.0/255.0, green: 154.0/255.0, blue: 158.0/255.0, alpha: 1.0)
    case .url:
        return UIColor(red: 45.0/255.0, green: 113.0/255.0, blue: 178.0/255.0, alpha: 1.0)
    case .textLink:
        return UIColor(red: 45.0/255.0, green: 113.0/255.0, blue: 178.0/255.0, alpha: 1.0)
    default:
        return .black
    }
}

If there is no UIColor returned from foregroundHighlightedColor, an alpha of 0.5 is applied to the set text color when a link is detected.

To set your own text highlight colors, return the desired UIColor within the closure value of underlineStyle:

contextLabel.foregroundHighlightedColor = { (linkResult) in
    return .lightGray
}

Underline style

By default detected links are not underlined.

To set your own underline style, return the desired NSUnderlineStyle within the closure value of underlineStyle:

contextLabel.underlineStyle = { (linkResult) in
    return .styleNone
}

Text links

ContextLabel automatically recognizes words starting with # and @ as well as manually defined text links.

A text link is defined at the minimum by a string ”text link” and an action which is a closure that gets called when the user touches the defined text. From version 0.3.1, all occurencies of a given text are recognized within the label text. To limit the recognition within the label text, an optional range can be set when initializing a TextLink.

TextLink(text: String, range: NSRange? = nil, options: NSString.CompareOptions = [], action: @escaping ()->())

Selection handling

When tapping the label, the closure didTouch: (TouchResult) -> Void will be called for each touch state:

didTouch: { [weak self] (touchResult) in
    switch touchResult.state {
    case .began:
        // Do something
    case .ended:
				// Do something
    default:
        break
    }
}

The touch behaviour changed from version 1.2.0.

The touchResult includes everything you need to take action on the selected string.

public struct TouchResult {
    public let linkResult: LinkResult?
    public let touches: Set<UITouch>
    public let event: UIEvent?
    public let state: UIGestureRecognizerState
}

public struct LinkResult {
    public let detectionType: ContextLabel.LinkDetectionType
    public let range: NSRange
    public let text: String
    public let textLink: TextLink?
}

public enum LinkDetectionType {
    case none
    case userHandle
    case hashtag
    case url
    case textLink
}

Use of cache

When setting the text, ContextLabel generates an instance of ’ContextLabelData’ which is a NSObject subclass that can be persisted in order to enable reuse for unchanged data.

’ContextLabelData’ holds the actual attributedString, the linkRangeResults and a userInfo dictionary which can be used to compare against the model data to see if it’s still valid.

if let cachedContextLabelData: ContextLabelData = … {
	// Set cached contextLabelData
	contextLabel.contextLabelData = cachedTextContextLabelData
} else {
	// Set label text
	contextLabel.text = text

	// Cache contextLabelData that has been generated from contextLabel
	cacheContextLabelData(contextLabel.contextLabelData)
}

License & Credits

ContextLabel is available under the MIT license.

ContextLabel was inspired by KILabel (https://github.com/Krelborn/KILabel).

zaidfadhil/ContextLabel