Making text bold using attributed string in swift

Question

I have a string like this

var str = "@text1 this is good @text1"

Now replace text1 with another string, say t 1. I am able to replace the text, but i am not able to bold it. I want to bold the new string t 1, so that the final output will be:

@t 1 this is good @t 1

How can I do it?

All the examples I am seeing are in Objective-C, but I want to do it in Swift.

Thanks in advance.

Answer 1

Usage:

let label = UILabel()
label.attributedText =
    NSMutableAttributedString()
        .bold("Address: ")
        .normal(" Kathmandu, Nepal\n\n")
        .orangeHighlight(" Email: ")
        .blackHighlight(" [email protected] ")
        .bold("\n\nCopyright: ")
        .underlined(" All rights reserved. 2020.")

Result:

Here is a neat way to make a combination of bold and normal texts in a single label plus some other bonus methods.

Extension: Swift 5.*

extension NSMutableAttributedString {
    var fontSize:CGFloat { return 14 }
    var boldFont:UIFont { return UIFont(name: "AvenirNext-Bold", size: fontSize) ?? UIFont.boldSystemFont(ofSize: fontSize) }
    var normalFont:UIFont { return UIFont(name: "AvenirNext-Regular", size: fontSize) ?? UIFont.systemFont(ofSize: fontSize)}

    func bold(_ value:String) -> NSMutableAttributedString {

        let attributes:[NSAttributedString.Key : Any] = [
            .font : boldFont
        ]

        self.append(NSAttributedString(string: value, attributes:attributes))
        return self
    }

    func normal(_ value:String) -> NSMutableAttributedString {

        let attributes:[NSAttributedString.Key : Any] = [
            .font : normalFont,
        ]

        self.append(NSAttributedString(string: value, attributes:attributes))
        return self
    }
    /* Other styling methods */
    func orangeHighlight(_ value:String) -> NSMutableAttributedString {

        let attributes:[NSAttributedString.Key : Any] = [
            .font :  normalFont,
            .foregroundColor : UIColor.white,
            .backgroundColor : UIColor.orange
        ]

        self.append(NSAttributedString(string: value, attributes:attributes))
        return self
    }

    func blackHighlight(_ value:String) -> NSMutableAttributedString {

        let attributes:[NSAttributedString.Key : Any] = [
            .font :  normalFont,
            .foregroundColor : UIColor.white,
            .backgroundColor : UIColor.black

        ]

        self.append(NSAttributedString(string: value, attributes:attributes))
        return self
    }

    func underlined(_ value:String) -> NSMutableAttributedString {

        let attributes:[NSAttributedString.Key : Any] = [
            .font :  normalFont,
            .underlineStyle : NSUnderlineStyle.single.rawValue

        ]

        self.append(NSAttributedString(string: value, attributes:attributes))
        return self
    }
}