Pfthb

I'm trying to learn about NSMutableAttributedString and NSAttributedString so I've created a simple playground to try some things. However, I have a couple of issues I can't figure out even after looking at a lot of examples on SO (like here and NSRange from Swift Range? elsewhere.

The problem is with the length property. If I specify the length as attribLabelText.length it causes an uncaught exception. If I specify attribLabelText.length - 1 there's no error, but only the letters 'Repor' have the attributes I'm setting:

import UIKit
import PlaygroundSupport

class MyViewController : UIViewController 
 override func loadView() 
 let view = UIView()
 view.backgroundColor = .white

 let label = getLabel1(labelText: "Report")
 view.addSubview(label)
 self.view = view
 


func getLabel1(labelText: String) -> UILabel 
 let label = UILabel()
 label.frame = CGRect(x: 150, y: 200, width: 200, height: 20)
 label.textColor = .black

 let attribLabelText: NSMutableAttributedString = NSMutableAttributedString(string: labelText)
 let attributes = [
 NSAttributedString.Key.foregroundColor : UIColor.gray.cgColor,
 NSAttributedString.Key.font : UIFont.boldSystemFont(ofSize: 14)
 ] as [NSAttributedString.Key : Any]

 attribLabelText.addAttributes(attributes, range: NSRange(location: 0, length: attribLabelText.length)) <-- this causes an uncaught exception of type NSException

 label.attributedText = attribLabelText

 return label

// Present the view controller in the Live View window
PlaygroundPage.current.liveView = MyViewController()

I have a feeling this is going to be something obvious but I'm out of ideas to try. Can anybody point out what I'm doing wrong?

You should be passing a UIColor for the foreground color instead of a CGColor.

UILabel seems to use the foreground color attribute slightly differently when drawing the string based on whether the attribute covers the entire range of the string or just a subrange.

The version it uses when the attribute covers the entire string only works with UIColor but the version it uses when the attribute only covers a substring seems to also work with CGColor (though this behavior isn't documented so it shouldn't be relied on) which explains why adding the -1 to the range avoids the exception.