I have a simple question concerning NSMutableAttributedString (or NSAttributedString).
Is it possible to do the following.
Supposing the string I want to display is: "Hello\nWorld"
(Hello on the first line an World on the second)
Is it possible to have the first line (Hello) left aligned and the second line (World) right aligned?
If the answer is YES, how can I do that?
This can be achieved using NSParagraphStyle:
#IBOutlet weak var label: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
let paragraphStyle1 = NSMutableParagraphStyle()
paragraphStyle1.alignment = .left
let paragraphStyle2 = NSMutableParagraphStyle()
paragraphStyle2.alignment = .right
let attrString = NSMutableAttributedString.init(string: "Hello \n World")
if let range = attrString.string.range(of: "Hello") {
let nsrange = attrString.string.nsRange(from: range)
attrString.addAttributes([NSAttributedStringKey.paragraphStyle: paragraphStyle1], range: nsrange)
}
if let range = attrString.string.range(of: "World") {
let nsrange = attrString.string.nsRange(from: range)
attrString.addAttributes([NSAttributedStringKey.paragraphStyle: paragraphStyle2], range: nsrange)
}
self.label.textAlignment = .right
self.label.attributedText = attrString
}
Output:
Related
I have a table view, inside the table view I have multiple cells as shows in attached image.
I want to show amenities items like : air conditioning, swimming pool, gym, tv cable etc like bullets.
How can I achieve this
I have all these value in my model coming from API response.
let ac = "Air Conditioning"
let tv = "TV Cable"
let washing = "Washing Machine"
let connectivity = "Wi-Fi"
let gym = "Gym"
Good case for stack views...
Vertical UIStackView
Each "row" is a Horizontal UIStackView with Distribution: Fill Equally
Looks like this - showing Bounds Rectangles:
without the Bounds Rectangles:
view hierarchy:
Edit
A second approach (which you may find easier)...
Use a single horizontal stack view with a single label on each "side" and use .attributedText.
Set the .attributedText of each label to a formatted, bulleted attributed string.
The cell prototype could look like this:
Then, use this code (slightly modified from https://stackoverflow.com/a/46889728/6257435) to generate a formatted, bulleted attributed string:
func add(bulletList strings: [String],
font: UIFont,
indentation: CGFloat = 15,
lineSpacing: CGFloat = 3,
paragraphSpacing: CGFloat = 10,
textColor: UIColor = .black,
bulletColor: UIColor = .red) -> NSAttributedString {
func createParagraphAttirbute() -> NSParagraphStyle {
var paragraphStyle: NSMutableParagraphStyle
let nonOptions = NSDictionary() as! [NSTextTab.OptionKey: Any]
paragraphStyle = NSParagraphStyle.default.mutableCopy() as! NSMutableParagraphStyle
paragraphStyle.tabStops = [
NSTextTab(textAlignment: .left, location: indentation, options: nonOptions)]
paragraphStyle.defaultTabInterval = indentation
paragraphStyle.firstLineHeadIndent = 0
paragraphStyle.lineSpacing = lineSpacing
paragraphStyle.paragraphSpacing = paragraphSpacing
paragraphStyle.headIndent = indentation
return paragraphStyle
}
let bulletPoint = "\u{2022}"
let textAttributes: [NSAttributedString.Key: Any] = [.font: font, .foregroundColor: textColor]
let bulletAttributes: [NSAttributedString.Key: Any] = [.font: font, .foregroundColor: bulletColor]
let buffer = NSMutableAttributedString.init()
for string in strings {
var formattedString = "\(bulletPoint)\t\(string)"
// don't add newLine if it's the last bullet
if string != strings.last {
formattedString += "\n"
}
let attributedString = NSMutableAttributedString(string: formattedString)
let paragraphStyle = createParagraphAttirbute()
attributedString.addAttributes(
[NSAttributedString.Key.paragraphStyle : paragraphStyle],
range: NSMakeRange(0, attributedString.length))
attributedString.addAttributes(
textAttributes,
range: NSMakeRange(0, attributedString.length))
let string:NSString = NSString(string: formattedString)
let rangeForBullet:NSRange = string.range(of: bulletPoint)
attributedString.addAttributes(bulletAttributes, range: rangeForBullet)
buffer.append(attributedString)
}
return buffer
}
A quick implementation of that using your image as sample data results in this:
I am using a kerning attribute on a UILabel to display its text with some custom letter spacing. Unfortunately, as I'm displaying user-generated strings, I sometimes see things like the following:
ie sometimes some emoji characters are not being displayed.
If I comment out the kerning but apply some paragraph style instead, I get the same kind of errored rendering.
I couldn't find anything in the documentation explicitely rejecting support for special unicode characters. Am I doing something wrong or is it an iOS bug?
The code to reproduce the bug is available as a playground here: https://github.com/Bootstragram/Playgrounds/tree/master/LabelWithEmoji.playground
and copied here:
//: A UIKit based Playground for presenting user interface
import UIKit
import PlaygroundSupport
extension NSAttributedString {
static func kernedSpacedText(_ text: String,
letterSpacing: CGFloat = 0.0,
lineHeight: CGFloat? = nil) -> NSAttributedString {
// TODO add the font attribute
let attributedString = NSMutableAttributedString(string: text)
attributedString.addAttribute(NSAttributedStringKey.kern,
value: letterSpacing,
range: NSRange(location: 0, length: text.count))
if let lineHeight = lineHeight {
let paragraphStyle = NSMutableParagraphStyle()
paragraphStyle.lineSpacing = lineHeight
attributedString.addAttribute(NSAttributedStringKey.paragraphStyle,
value: paragraphStyle,
range: NSRange(location: 0, length: text.count))
}
return attributedString
}
}
//for familyName in UIFont.familyNames {
// for fontName in UIFont.fontNames(forFamilyName: familyName) {
// print(fontName)
// }
//}
class MyViewController : UIViewController {
override func loadView() {
let view = UIView()
view.backgroundColor = .white
let myString = "1⚽📺🍻⚾️🌯🏄♂️👍\n2 😀💿💸 🍻"
let label = UILabel()
label.frame = CGRect(x: 150, y: 200, width: 200, height: 100)
label.attributedText = NSAttributedString.kernedSpacedText(myString)
label.numberOfLines = 0
label.textColor = .black
view.addSubview(label)
self.view = view
}
}
// Present the view controller in the Live View window
PlaygroundPage.current.liveView = MyViewController()
Thanks.
TL, DR:
String.count != NSString.length. Any time you see NSRange, you must convert your String into UTF-16:
static func kernedSpacedText(_ text: String,
letterSpacing: CGFloat = 0.0,
lineHeight: CGFloat? = nil) -> NSAttributedString {
// TODO add the font attribute
let attributedString = NSMutableAttributedString(string: text)
attributedString.addAttribute(NSAttributedStringKey.kern,
value: letterSpacing,
range: NSRange(location: 0, length: text.utf16.count))
if let lineHeight = lineHeight {
let paragraphStyle = NSMutableParagraphStyle()
paragraphStyle.lineSpacing = lineHeight
attributedString.addAttribute(NSAttributedStringKey.paragraphStyle,
value: paragraphStyle,
range: NSRange(location: 0, length: text.utf16.count))
}
return attributedString
}
The longer explanation
Yours is a common problem converting between Swift's String and ObjC's NSString. The length of a String is the number of extended grapheme clusters; in ObjC, it's the number of UTF-16 code points needed to encode that string.
Take the thumb-up character for example:
let str = "👍"
let nsStr = str as NSString
print(str.count) // 1
print(nsStr.length) // 2
Things can get even weirder when it comes to the flag emojis:
let str = "🇺🇸"
let nsStr = str as NSString
print(str.count) // 1
print(nsStr.length) // 4
Even though this article was written all the way back in 2003, it's still a good read today:
The Absolute Minimum Every Software Developer Absolutely, Positively Must Know About Unicode and Character Sets.
I have a custom view, on top of this view I have a UILabel. The label placed in the middle of the view. The label shows current speed. The label's text size of an integer part is bigger than text size of a fractional part. I use monospacedDigitFont in both parts of the label's text to prevent the text shaking / moving when numbers change and NSMutableAttributedString to be able to set different size of the label's text. Apparently it does not work.
The custom view:
Snippet of code:
func updateSpeed(){
dummySpeed += 4.0
speedometerView.currentSpeed = speedometerView.setSmoothSpeed(SpdAv: dummySpeed)
let myString = String(Float(round(speedometerView.currentSpeed * 10) / 10))
let attrString = NSMutableAttributedString(string: myString as String)
attrString.addAttribute(NSFontAttributeName, value: currentSpeedLabel.font.monospacedDigitFont, range: NSMakeRange(0, 1))
attrString.addAttribute(NSFontAttributeName, value: currentSpeedLabel.font.monospacedDigitFont.withSize(20), range: NSMakeRange(2, 1))
currentSpeedLabel.attributedText = attrString
}
What do I do wrong?
Well it is not that easy if you are a newbie in iOS.
Here it is a solution:
#IBOutlet weak var currentSpeedLabel: UILabel! {
didSet{
currentSpeedLabel.font = UIFont.monospacedDigitSystemFont(
ofSize: UIFont.systemFontSize * 2,
weight: UIFontWeightRegular)
}
}
func updateSpeed(){
dummySpeed += 4.0
speedometerView.currentSpeed = speedometerView.setSmoothSpeed(SpdAv: dummySpeed)
let myString = String(Float(round(speedometerView.currentSpeed * 10) / 10))
let attrString = NSMutableAttributedString(string: myString as String)
attrString.addAttribute(NSFontAttributeName, value: UIFont.monospacedDigitSystemFont(
ofSize: UIFont.systemFontSize,
weight: UIFontWeightRegular), range: NSMakeRange(attrString.length - 1, 1))
currentSpeedLabel.attributedText = attrString
}
I have a UILabel on xib file and I want to increase the line spacing of the texts.
I tried to write, but with the code below only text alignment is called and line spacing remains the same. Why "paragraphStyle.lineSpacing" is not called?
class PlaySheetCellLeft: UITableViewCell {
#IBOutlet var LBLTitle:UILabel!
var message:[String:Any]? {
didSet{
guard let msg = self.message else { return }
self.LBLTitle.text = title
}
override func awakeFromNib() {
super.awakeFromNib()
let paragraphStyle = NSMutableParagraphStyle()
paragraphStyle.lineSpacing = 10
let attrString = NSMutableAttributedString()
attrString.addAttribute(NSParagraphStyleAttributeName, value:paragraphStyle, range:NSMakeRange(0, attrString.length))
LBLTitle.attributedText = attrString
LBLTitle.textAlignment = NSTextAlignment.center
}
}
You're creating a range with an empty attributed string, so the style isn't being set on anything.
When you create your range, you're actually creating a range like this: NSMakeRange(0, 0).
You should pass your string into the creation of the mutable attributed string like this: NSMutableAttributedString(string: "your string")
You'll also need to set this when you set the text of your label, which by the looks of your code isn't in awakeFromNib
I've been working on a small project using Xcode. It uses a lot of labels, textfields, etc. I've finished with most of the layout, the constrains, and the forms, titles, etc. After which, the client announces that for all required fields, there should be a red asterisk next to the label.
Call me lazy, but I'd rather not go back to all of my forms, add in a lot of labels with asterisks on them, and re-do my auto-layout to accommodate the new labels.
So, is there a way to change the colour of a specific character (in this case, the asterisk) in a UILabel, while the rest of the text stays black?
You can use NSMutableAttributedString.
You can set specific range of your string with different color, font, size, ...
E.g:
var range = NSRange(location:2,length:1) // specific location. This means "range" handle 1 character at location 2
attributedString = NSMutableAttributedString(string: originalString, attributes: [NSFontAttributeName:UIFont(name: "Georgia", size: 18.0)!])
// here you change the character to red color
attributedString.addAttribute(NSForegroundColorAttributeName, value: UIColor.redColor(), range: range)
label.attributedText = attributedString
Ref: Use multiple font colors in a single label - Swift
You can change a lot of attribute of String.
Ref from apple: https://developer.apple.com/library/prerelease/ios/documentation/Cocoa/Reference/Foundation/Classes/NSMutableAttributedString_Class/index.html
let text = "Sample text *"
let range = (text as NSString).rangeOfString("*")
let attributedString = NSMutableAttributedString(string:text)
attributedString.addAttribute(NSForegroundColorAttributeName, value: UIColor.redColor() , range: range)
//Apply to the label
myLabel.attributedText = attributedString;
UILabel have an .attributedText property of type NSAttributedString.
Declaration
#NSCopying var attributedText: NSAttributedString?
You let your asterix * have a single .redColor() attribute (NSForegroundColorAttributeName), whereas the rest of the new label simply uses the same text as before, however also contained in an NSAttributedTextString.
An example follows below using a function to repeatedly update your existing labels to attributed strings prefixed with a red *:
class ViewController: UIViewController {
#IBOutlet weak var myFirstLabel: UILabel!
#IBOutlet weak var mySecondLabel: UILabel!
let myPrefixCharacter = "*"
let myPrefixColor = UIColor.redColor()
// ...
override func viewDidLoad() {
super.viewDidLoad()
// ...
/* update labels to attributed strings */
updateLabelToAttributedString(myFirstLabel)
updateLabelToAttributedString(mySecondLabel)
// ...
}
func updateLabelToAttributedString(label: UILabel) {
/* original label text as NSAttributedString, prefixed with " " */
let attr = [ NSForegroundColorAttributeName: myPrefixColor ]
let myNewLabelText = NSMutableAttributedString(string: myPrefixCharacter, attributes: attr)
let myOrigLabelText = NSAttributedString(string: " " + (label.text ?? ""))
/* set new label text as attributed string */
myNewLabelText.appendAttributedString(myOrigLabelText)
label.attributedText = myNewLabelText
}
// ...
}
Swift 4
(Note: notation for attributed string key is changed in swift 4)
Here is an extension for NSMutableAttributedString, that add/set color on string/text.
extension NSMutableAttributedString {
func setColor(color: UIColor, forText stringValue: String) {
let range: NSRange = self.mutableString.range(of: stringValue, options: .caseInsensitive)
self.addAttribute(NSAttributedStringKey.foregroundColor, value: color, range: range)
}
}
Now, try above extension with UILabel and see result
let label = UILabel()
label.frame = CGRect(x: 40, y: 100, width: 280, height: 200)
let red = "red"
let blue = "blue"
let green = "green"
let stringValue = "\(red)\n\(blue)\n&\n\(green)"
label.textColor = UIColor.lightGray
label.numberOfLines = 0
let attributedString: NSMutableAttributedString = NSMutableAttributedString(string: stringValue)
attributedString.setColor(color: UIColor.red, forText: red) // or use direct value for text "red"
attributedString.setColor(color: UIColor.blue, forText: blue) // or use direct value for text "blue"
attributedString.setColor(color: UIColor.green, forText: green) // or use direct value for text "green"
label.font = UIFont.systemFont(ofSize: 26)
label.attributedText = attributedString
self.view.addSubview(label)
func updateAttributedStringWithCharacter(title : String, uilabel: UILabel) {
let text = title + "*"
let range = (text as NSString).range(of: "*")
let attributedString = NSMutableAttributedString(string:text)
attributedString.addAttribute(NSAttributedString.Key.foregroundColor, value: UIColor.red , range: range)
uilabel.attributedText = attributedString }
I know this is an old post, but i want to share my approach (which is based on the answer from dfri) i just made it a function for convenience.
func lastCharOnColor(label: UILabel, color: UIColor, length: Int) {
//First we get the text.
let string = label.text
//Get number of characters on string and based on that get last character index.
let characterCounter = string?.characters.count
let lastCharacterIndex = characterCounter!-1
//Set Range
let range = NSRange(location: lastCharacterIndex, length: length)
let attributedString = NSMutableAttributedString(string: string!, attributes: nil)
//Set label
attributedString.addAttribute(NSForegroundColorAttributeName, value: color, range: range)
label.attributedText = attributedString
}
I use this function to just set the last character from a label to a certain color like this:
lastCharOnColor(label: self.labelname, color: UIColor.red, length: 1)
Hope this helps anyone.
Here is an extension for simply making mandatory labels by appending a red *
Swift 5
extension UILabel {
func makeTextMandatory() {
let text = self.text ?? "" + " *"
let range = (text as NSString).range(of: " *")
let attributedString = NSMutableAttributedString(string:text)
attributedString.addAttribute(NSAttributedString.Key.foregroundColor, value: UIColor.red , range: range)
self.attributedText = attributedString
}
}
Usage :
dobLabel.makeTextMandatory()