问题
I have a UILabel I've made programmatically as:
var label = UILabel()
I've then declared some styling for the label, including a font, such as:
label.frame = CGRect(x: 20, y: myHeaderView.frame.height / 2, width: 300, height: 30)
label.font = UIFont(name: "Typo GeoSlab Regular Demo", size: 15)
label.textColor = UIColor(hue: 0/360, saturation: 0/100, brightness: 91/100, alpha: 1)
The first part of the label will always read : "Filter:" then followed by another part of the string, for example, "Most popular"
I would like the word filter to be in bold, so the whole thing would look like:
Filter: Most popular
I want to simplest way of creating this effect. I've been searching the internet for how to achieve this and there are so many ways, some which just look like pages of code. And most of it seems to be in Objective-C. I would like it in Swift please :)
I don't know if i'm on the right lines, but is this what NSRange can help achieve? Thanks in advance
Update
I use a series of if statements to change my label variable. Such as:
if indexArray == 1 {
label.text = "Filter: Film name"
} else if indexArray == 2 {
label.text = "Filter: Most popular"
} else if indexArray == 3 {
label.text = "Filter: Star rating"
}
回答1:
You will want to use attributedString which allows you to style parts of a string etc. This can be done like this by having two styles, one normal, one bold, and then attaching them together:
let boldText = "Filter:"
let attrs = [NSAttributedString.Key.font : UIFont.boldSystemFont(ofSize: 15)]
let attributedString = NSMutableAttributedString(string:boldText, attributes:attrs)
let normalText = "Hi am normal"
let normalString = NSMutableAttributedString(string:normalText)
attributedString.append(normalString)
When you want to assign it to a label:
label.attributedText = attributedString
回答2:
You can use NSMutableAttributedString and NSAttributedString to create customized string. The function below makes given boldString bold in given string.
Swift 3
func attributedText(withString string: String, boldString: String, font: UIFont) -> NSAttributedString {
let attributedString = NSMutableAttributedString(string: string,
attributes: [NSFontAttributeName: font])
let boldFontAttribute: [String: Any] = [NSFontAttributeName: UIFont.boldSystemFont(ofSize: font.pointSize)]
let range = (string as NSString).range(of: boldString)
attributedString.addAttributes(boldFontAttribute, range: range)
return attributedString
}
Example usage
authorLabel.attributedText = attributedText(withString: String(format: "Author : %@", user.name), boldString: "Author", font: authorLabel.font)
Swift 4
func attributedText(withString string: String, boldString: String, font: UIFont) -> NSAttributedString {
let attributedString = NSMutableAttributedString(string: string,
attributes: [NSAttributedStringKey.font: font])
let boldFontAttribute: [NSAttributedStringKey: Any] = [NSAttributedStringKey.font: UIFont.boldSystemFont(ofSize: font.pointSize)]
let range = (string as NSString).range(of: boldString)
attributedString.addAttributes(boldFontAttribute, range: range)
return attributedString
}
Swift 4.2 and 5
func attributedText(withString string: String, boldString: String, font: UIFont) -> NSAttributedString {
let attributedString = NSMutableAttributedString(string: string,
attributes: [NSAttributedString.Key.font: font])
let boldFontAttribute: [NSAttributedString.Key: Any] = [NSAttributedString.Key.font: UIFont.boldSystemFont(ofSize: font.pointSize)]
let range = (string as NSString).range(of: boldString)
attributedString.addAttributes(boldFontAttribute, range: range)
return attributedString
}
回答3:
Result:
Swift 4.2 & 5.0:
First off we create a protocol that both UILabel and UITextField can adopt.
public protocol ChangableFont: AnyObject {
var text: String? { get set }
var attributedText: NSAttributedString? { get set }
var rangedAttributes: [RangedAttributes] { get }
func getFont() -> UIFont?
func changeFont(ofText text: String, with font: UIFont)
func changeFont(inRange range: NSRange, with font: UIFont)
func changeTextColor(ofText text: String, with color: UIColor)
func changeTextColor(inRange range: NSRange, with color: UIColor)
func resetFontChanges()
}
We want to be able to add multiple changes to our text, therefore we create the rangedAttributes property. It's a custom struct that holds attributes and the range in which they are applied.
public struct RangedAttributes {
let attributes: [NSAttributedString.Key: Any]
let range: NSRange
public init(_ attributes: [NSAttributedString.Key: Any], inRange range: NSRange) {
self.attributes = attributes
self.range = range
}
}
Another problem is that UILabel its font property is strong and UITextField its font property is weak/optional. To make them both work with our ChangableFont protocol we include the getFont() -> UIFont? method.
extension UILabel: ChangableFont {
public func getFont() -> UIFont? {
return font
}
}
extension UITextField: ChangableFont {
public func getFont() -> UIFont? {
return font
}
}
Now we can go ahead and create the default implementation for both UILabel and UITextField by extending our protocol.
public extension ChangableFont {
public var rangedAttributes: [RangedAttributes] {
guard let attributedText = attributedText else {
return []
}
var rangedAttributes: [RangedAttributes] = []
let fullRange = NSRange(
location: 0,
length: attributedText.string.count
)
attributedText.enumerateAttributes(
in: fullRange,
options: []
) { (attributes, range, stop) in
guard range != fullRange, !attributes.isEmpty else { return }
rangedAttributes.append(RangedAttributes(attributes, inRange: range))
}
return rangedAttributes
}
public func changeFont(ofText text: String, with font: UIFont) {
guard let range = (self.attributedText?.string ?? self.text)?.range(ofText: text) else { return }
changeFont(inRange: range, with: font)
}
public func changeFont(inRange range: NSRange, with font: UIFont) {
add(attributes: [.font: font], inRange: range)
}
public func changeTextColor(ofText text: String, with color: UIColor) {
guard let range = (self.attributedText?.string ?? self.text)?.range(ofText: text) else { return }
changeTextColor(inRange: range, with: color)
}
public func changeTextColor(inRange range: NSRange, with color: UIColor) {
add(attributes: [.foregroundColor: color], inRange: range)
}
private func add(attributes: [NSAttributedString.Key: Any], inRange range: NSRange) {
guard !attributes.isEmpty else { return }
var rangedAttributes: [RangedAttributes] = self.rangedAttributes
var attributedString: NSMutableAttributedString
if let attributedText = attributedText {
attributedString = NSMutableAttributedString(attributedString: attributedText)
} else if let text = text {
attributedString = NSMutableAttributedString(string: text)
} else {
return
}
rangedAttributes.append(RangedAttributes(attributes, inRange: range))
rangedAttributes.forEach { (rangedAttributes) in
attributedString.addAttributes(
rangedAttributes.attributes,
range: rangedAttributes.range
)
}
attributedText = attributedString
}
public func resetFontChanges() {
guard let text = text else { return }
attributedText = NSMutableAttributedString(string: text)
}
}
With in the default implementation I use a little helper method for getting the NSRange of a substring.
public extension String {
public func range(ofText text: String) -> NSRange {
let fullText = self
let range = (fullText as NSString).range(of: text)
return range
}
}
We're done! You can now change parts of the text its font and text color.
titleLabel.text = "Welcome"
titleLabel.font = UIFont.systemFont(ofSize: 70, weight: .bold)
titleLabel.textColor = UIColor.black
titleLabel.changeFont(ofText: "lc", with: UIFont.systemFont(ofSize: 60, weight: .light))
titleLabel.changeTextColor(ofText: "el", with: UIColor.blue)
titleLabel.changeTextColor(ofText: "co", with: UIColor.red)
titleLabel.changeTextColor(ofText: "m", with: UIColor.green)
回答4:
Swift 4 alternative:
let attrs = [NSAttributedStringKey.font : UIFont.boldSystemFont(ofSize: 14)]
let attributedString = NSMutableAttributedString(string: "BOLD TEXT", attributes:attrs)
let normalString = NSMutableAttributedString(string: "normal text")
attributedString.append(normalString)
myLabel.attributedText = attributedString
回答5:
Just sharing my own quite-flexible implementation in Swift 4.0. Cause there are some requirements, like mine currently, that you need to set not only bold but italic the part of a label's text.
import UIKit
extension UILabel {
/** Sets up the label with two different kinds of attributes in its attributed text.
* @params:
* - primaryString: the normal attributed string.
* - secondaryString: the bold or highlighted string.
*/
func setAttributedText(primaryString: String, textColor: UIColor, font: UIFont, secondaryString: String, secondaryTextColor: UIColor, secondaryFont: UIFont) {
let completeString = "\(primaryString) \(secondaryString)"
let paragraphStyle = NSMutableParagraphStyle()
paragraphStyle.alignment = .center
let completeAttributedString = NSMutableAttributedString(
string: completeString, attributes: [
.font: font,
.foregroundColor: textColor,
.paragraphStyle: paragraphStyle
]
)
let secondStringAttribute: [NSAttributedStringKey: Any] = [
.font: secondaryFont,
.foregroundColor: secondaryTextColor,
.paragraphStyle: paragraphStyle
]
let range = (completeString as NSString).range(of: secondaryString)
completeAttributedString.addAttributes(secondStringAttribute, range: range)
self.attributedText = completeAttributedString
}
}
回答6:
You can directly do on String if you prefer:
extension String {
func withBoldText(text: String, font: UIFont? = nil) -> NSAttributedString {
let _font = font ?? UIFont.systemFont(ofSize: 14, weight: .regular)
let fullString = NSMutableAttributedString(string: self, attributes: [NSAttributedString.Key.font: _font])
let boldFontAttribute: [NSAttributedString.Key: Any] = [NSAttributedString.Key.font: UIFont.boldSystemFont(ofSize: _font.pointSize)]
let range = (self as NSString).range(of: text)
fullString.addAttributes(boldFontAttribute, range: range)
return fullString
}}
Usage:
label.attributeString = "my full string".withBoldText(text: "full")
回答7:
for the ones who prefer extensions
Swift 5.0
/// will set a regual and a bold text in the same label
public func setRegualAndBoldText(regualText: String,
boldiText: String) {
let attrs = [NSAttributedString.Key.font : UIFont.boldSystemFont(ofSize: font.pointSize)]
let regularString = NSMutableAttributedString(string: regualText)
let boldiString = NSMutableAttributedString(string: boldiText, attributes:attrs)
regularString.append(boldiString)
attributedText = regularString
}
and use:
label.setRegualAndBoldText(regualText: "height: ", boldiText: "1.65 :(")
回答8:
Swift 4.0 solution
let font = UIFont.systemFont(ofSize: 14)
func boldSearchResult(searchString: String, resultString: String) -> NSMutableAttributedString {
let attributedString: NSMutableAttributedString = NSMutableAttributedString(string: resultString)
guard let regex = try? NSRegularExpression(pattern: searchString.lowercased(), options: []) else {
return attributedString
}
let range: NSRange = NSMakeRange(0, resultString.count)
regex.enumerateMatches(in: resultString.lowercased(), options: [], range: range) { (textCheckingResult, matchingFlags, stop) in
guard let subRange = textCheckingResult?.range else {
return
}
attributedString.addAttributes([NSAttributedString.Key.font : font], range: subRange)
}
return attributedString
}
来源：https://stackoverflow.com/questions/36486761/make-part-of-a-uilabel-bold-in-swift