- April 27, 2024
- Mins Read
StyledText is a library that simplifies styling dynamic text in iOS applications. Instead of having to use attributed strings every time you need to update text, you can declaratively set a text style on your labels. When the text of the label is updated, the label uses the preset style.
let label = UILabel()
let paragraphStyle = NSMutableParagraphStyle()
paragraphStyle.lineSpacing = 4.0
let attributes: [String: Any] = [NSFontAttributeName: UIFont.boldSystemFont(ofSize: 14),
NSForegroundColorAttributeName: UIColor.blue,
NSKernAttributeName: 1.5,
NSParagraphStyleAttributeName: paragraphStyle]
let string = NSAttributedString(string: “This is a string”,
attributes: attributes)
label.attributedText = string
let newString = NSAttributedString(string: “This is a new string”,
attributes: attributes)
label.attributedText = newString
let styledLabel = StyledLabel()
styledLabel.textStyle = TextStyle(font: .boldSystemFont(ofSize: 14), color: .blue, lineSpacing: 4.0, kern: 1.5)
styledLabel.text = “This is a string”
styledLabel.text = “This is a new string”
pod “StyledText”
pod install
Getting started with StyledText is easy, just add a StyledLabel
to your view and provide it with a TextStyle
. After that, it behaves like any other UILabel
. Changes to the label’s text
property will always use the set textStyle
.
class ViewController: UIViewController {
private let styledLabel: StyledLabel = {
let label = StyledLabel(frame: .zero)
label.textStyle = TextStyle(font: .boldSystemFont(ofSize: 24.0),
color: .orange)
return label
}()
}
A TextStyle
represents the attributes a styled view should use to draw its text. Many different text formatting options are supported, including those that previously required interaction with attributed strings or paragraph styles, such as kerning and line spacing. Creating a TextStyle
is easy, just specify a font along with any other attributes you want to define. Any unspecified attributes simply remain as system defaults.
let style = TextStyle(font: .italicSystemFont(ofSize: 72),
color: .magenta,
lineSpacing: 10,
lineHeightMultiple: 2.0,
kern: -0.5,
alignment: .left,
lineBreakMode: .byTruncatingMiddle)
let blueStyle = style.with(color: .blue)
let redStyle = style.with(color: .red)
You probably have a sensible default value for kerning that works well for your font. Instead of needing to specify this kern value in each individual TextStyle
you create, you can use a TextStyleDefaultsGenerator
to add it automatically. The simplest way to get started with this is to extend TextStyle
to conform to the TextStyleDefaultsGenerator
protocol, the library will detect if you’ve added this conformance and behave appropriately.
extension TextStyle: TextStyleDefaultsGenerator {
private static let defaultCeraKern: CGFloat = -0.2
private static let defaultChronicleKern: CGFloat = -0.2
static public func defaultKern(for font: UIFont) -> CGFloat? {
if font.fontName.contains(“Cera”) {
return defaultCeraKern
} else if font.fontName.contains(“Chronicle”) {
return defaultChronicleKern
}
return nil
}
}
StyledText supports scaling text content to the system font size, a feature Apple calls Dynamic Type. To use this feature, set the dynamicTypeBehavior
property of a TextStyle
to one of these values:
noScaling
: [default] keep the font size constant, even when the system font size changesscaleToStandardSizes
: scale the font to all standard system font sizes, larger accessibility sizes are capped at the maximum standard sizescaleToAllSizes
: scale the font to all standard and accessiblity font sizesIt’s possible for the font size to change while your application is running. When this occurs, you’ll need to call refreshStyle()
on any styled components that are visible for the size to update. A good way to listen for this event is by adding a delegate to the shared DynamicTypeController
:
class MyViewController: UIViewController, DynamicTypeControllerDelegate {
let label: StyledLabel = {
let label = StyledLabel()
label.textStyle = TextStyle(font: .boldSystemFont(ofSize: 14), color: .black, dynamicTypeBehavior: .scaleToStandardSizes)
return label
}()
override func viewDidLoad() {
super.viewDidLoad()
DynamicTypeController.shared.addDelegate(self)
}
func preferredContentSizeCategoryDidUpdate(controller: DynamicTypeController, newCategory: UIContentSizeCategory){
label.refreshStyle()
}
}
To enable automatic styling, StyledText uses a number of view subclasses that are simple swap-in replacements for conventional UIKit components.
StyledText View | Replaces UIKit View |
---|---|
StyledLabel | UILabel |
StyledTextView | UITextView |
StyledButton* | UIButton |
StyledButton
provides text style properties for each UIControlState
button state.
Control State | Text Style Property |
---|---|
.normal | normalTextStyle |
.highlighted | highlightedTextStyle |
.disabled | disabledTextStyle |
.selected | selectedTextStyle |
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