I have a slider for a survey that display the following strings based on the value of the slider: "Very Bad, Bad, Okay, Good, Very Good".
Here is the code for the slider:
- (IBAction) sliderValueChanged:(UISlider *)sender {
scanLabel.text = [NSString stringWithFormat:@" %.f", [sender value]];
NSArray *texts=[NSArray arrayWithObjects:@"Very Bad", @"Bad", @"Okay", @"Good", @"Very Good", @"Very Good", nil];
NSInteger sliderValue=[sender value]; //make the slider value in given range integer one.
self.scanLabel.text=[texts objectAtIndex:sliderValue];
}
I want "Very Bad" to be red, "Bad" to be orange, "Okay" to be yellow, "Good" and "Very Good" to be green.
I don't understand how to use NSAttributedString
to get this done.
This question is related to
ios
cocoa-touch
nsattributedstring
There is no need for using NSAttributedString
. All you need is a simple label with the proper textColor
. Plus this simple solution will work with all versions of iOS, not just iOS 6.
But if you needlessly wish to use NSAttributedString
, you can do something like this:
UIColor *color = [UIColor redColor]; // select needed color
NSString *string = ... // the string to colorize
NSDictionary *attrs = @{ NSForegroundColorAttributeName : color };
NSAttributedString *attrStr = [[NSAttributedString alloc] initWithString:string attributes:attrs];
self.scanLabel.attributedText = attrStr;
You can create NSAttributedString
NSDictionary *attributes = @{ NSForegroundColorAttributeName : [UIColor redColor] };
NSAttributedString *attrStr = [[NSAttributedString alloc] initWithString:@"My Color String" attributes:attrs];
OR NSMutableAttributedString
to apply custom attributes with Ranges.
NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:[NSString stringWithFormat:@"%@%@", methodPrefix, method] attributes: @{ NSFontAttributeName : FONT_MYRIADPRO(48) }];
[attributedString addAttribute:NSFontAttributeName value:FONT_MYRIADPRO_SEMIBOLD(48) range:NSMakeRange(methodPrefix.length, method.length)];
Available Attributes: NSAttributedStringKey
UPDATE:
let message: String = greeting + someMessage
let paragraphStyle = NSMutableParagraphStyle()
paragraphStyle.lineSpacing = 2.0
// Note: UIFont(appFontFamily:ofSize:) is extended init.
let regularAttributes: [NSAttributedString.Key : Any] = [.font : UIFont(appFontFamily: .regular, ofSize: 15)!, .paragraphStyle : paragraphStyle]
let boldAttributes = [NSAttributedString.Key.font : UIFont(appFontFamily: .semiBold, ofSize: 15)!]
let mutableString = NSMutableAttributedString(string: message, attributes: regularAttributes)
mutableString.addAttributes(boldAttributes, range: NSMakeRange(0, greeting.count))
With Swift 4, NSAttributedStringKey
has a static property called foregroundColor
. foregroundColor
has the following declaration:
static let foregroundColor: NSAttributedStringKey
The value of this attribute is a
UIColor
object. Use this attribute to specify the color of the text during rendering. If you do not specify this attribute, the text is rendered in black.
The following Playground code shows how to set the text color of an NSAttributedString
instance with foregroundColor
:
import UIKit
let string = "Some text"
let attributes = [NSAttributedStringKey.foregroundColor : UIColor.red]
let attributedString = NSAttributedString(string: string, attributes: attributes)
The code below shows a possible UIViewController
implementation that relies on NSAttributedString
in order to update the text and text color of a UILabel
from a UISlider
:
import UIKit
enum Status: Int {
case veryBad = 0, bad, okay, good, veryGood
var display: (text: String, color: UIColor) {
switch self {
case .veryBad: return ("Very bad", .red)
case .bad: return ("Bad", .orange)
case .okay: return ("Okay", .yellow)
case .good: return ("Good", .green)
case .veryGood: return ("Very good", .blue)
}
}
static let minimumValue = Status.veryBad.rawValue
static let maximumValue = Status.veryGood.rawValue
}
final class ViewController: UIViewController {
@IBOutlet weak var label: UILabel!
@IBOutlet weak var slider: UISlider!
var currentStatus: Status = Status.veryBad {
didSet {
// currentStatus is our model. Observe its changes to update our display
updateDisplay()
}
}
override func viewDidLoad() {
super.viewDidLoad()
// Prepare slider
slider.minimumValue = Float(Status.minimumValue)
slider.maximumValue = Float(Status.maximumValue)
// Set display
updateDisplay()
}
func updateDisplay() {
let attributes = [NSAttributedStringKey.foregroundColor : currentStatus.display.color]
let attributedString = NSAttributedString(string: currentStatus.display.text, attributes: attributes)
label.attributedText = attributedString
slider.value = Float(currentStatus.rawValue)
}
@IBAction func updateCurrentStatus(_ sender: UISlider) {
let value = Int(sender.value.rounded())
guard let status = Status(rawValue: value) else { fatalError("Could not get Status object from value") }
currentStatus = status
}
}
Note however that you don't really need to use NSAttributedString
for such an example and can simply rely on UILabel
's text
and textColor
properties. Therefore, you can replace your updateDisplay()
implementation with the following code:
func updateDisplay() {
label.text = currentStatus.display.text
label.textColor = currentStatus.display.color
slider.value = Float(currentStatus.rawValue)
}
For Swift 5:
var attributes = [NSAttributedString.Key: AnyObject]()
attributes[.foregroundColor] = UIColor.red
let attributedString = NSAttributedString(string: "Very Bad", attributes: attributes)
label.attributedText = attributedString
For Swift 4:
var attributes = [NSAttributedStringKey: AnyObject]()
attributes[.foregroundColor] = UIColor.red
let attributedString = NSAttributedString(string: "Very Bad", attributes: attributes)
label.attributedText = attributedString
For Swift 3:
var attributes = [String: AnyObject]()
attributes[NSForegroundColorAttributeName] = UIColor.red
let attributedString = NSAttributedString(string: "Very Bad", attributes: attributes)
label.attributedText = attributedString
Update for Swift 4.2
var attributes = [NSAttributedString.Key: AnyObject]()
attributes[.foregroundColor] = UIColor.blue
let attributedString = NSAttributedString(string: "Very Bad",
attributes: attributes)
label.attributedText = attributedString
Use something like this (Not compiler checked)
NSMutableAttributedString *string = [[NSMutableAttributedString alloc]initWithString:self.text.text];
NSRange range=[self.myLabel.text rangeOfString:texts[sliderValue]]; //myLabel is the outlet from where you will get the text, it can be same or different
NSArray *colors=@[[UIColor redColor],
[UIColor redColor],
[UIColor yellowColor],
[UIColor greenColor]
];
[string addAttribute:NSForegroundColorAttributeName
value:colors[sliderValue]
range:range];
[self.scanLabel setAttributedText:texts[sliderValue]];
One liner for Swift:
NSAttributedString(string: "Red Text", attributes: [.foregroundColor: UIColor.red])
In Swift 4:
// Custom color
let greenColor = UIColor(red: 10/255, green: 190/255, blue: 50/255, alpha: 1)
// create the attributed colour
let attributedStringColor = [NSAttributedStringKey.foregroundColor : greenColor];
// create the attributed string
let attributedString = NSAttributedString(string: "Hello World!", attributes: attributedStringColor)
// Set the label
label.attributedText = attributedString
In Swift 3:
// Custom color
let greenColor = UIColor(red: 10/255, green: 190/255, blue: 50/255, alpha: 1)
// create the attributed color
let attributedStringColor : NSDictionary = [NSForegroundColorAttributeName : greenColor];
// create the attributed string
let attributedString = NSAttributedString(string: "Hello World!", attributes: attributedStringColor as? [String : AnyObject])
// Set the label
label.attributedText = attributedString
Enjoy.
Source: Stackoverflow.com