iOS Swift Change Particular Text Color Inside Label Programatically

Question

I'm having some search option in my app, which will highlight given word in UISearchBar. Given word may occurs multiple time in label I need t highlight all those words. How it is possible, I have tried with some set of codes but It will highlight only one occurrence of that word, Here is my sample code:

var SearchAttributeText = "The"
let range = (TextValue as NSString).range(of: SearchAttributeText)
let attribute = NSMutableAttributedString.init(string: TextValue)
attribute.addAttribute(NSForegroundColorAttributeName, value: UIColor.red , range: range)
self.label.attributedText = attribute

Need to support with both Upper and lower cases. Word The may occurs multiple time need to highlight all.

See this tutorial : https://iosdevcenters.blogspot.com/2015/12/how-to-set-use-multiple-font-colors-in.html — Bhadresh, Dec 11 '17 at 08:51
@Bhadresh I already referred this blog they change color based on range not based to given character — Kavin Kumar Arumugam, Dec 11 '17 at 08:56
Get all ranges of the particular substring with the help of [this question](https://stackoverflow.com/questions/36865443/get-all-ranges-of-a-substring-in-a-string-in-swift) and iterate through them. — Tamás Sengel, Dec 11 '17 at 09:15
You can use a `NSRegularExpression` or a for loop on `range(of:)` (note that `range(of:)` has "variants" with options like case insensitive) to get all ranges of the occurrences of your searched text. — Larme, Dec 11 '17 at 09:40

Indrajeet · Accepted Answer · 2017-12-11T12:37:54.000

You can use following code to search in string

    //Text need to be searched
    let SearchAttributeText = "the"

    //Store label text in variable as NSString
    let contentString = lblContent.text! as NSString

    //Create range of label text
    var rangeString = NSMakeRange(0, contentString.length)

    //Convert label text into attributed string
    let attribute = NSMutableAttributedString.init(string: contentString as String)

    while (rangeString.length != NSNotFound && rangeString.location != NSNotFound) {

        //Get the range of search text
        let colorRange = (lblContent.text?.lowercased() as! NSString).range(of: SearchAttributeText, options: NSString.CompareOptions(rawValue: 0), range: rangeString)

        if (colorRange.location == NSNotFound) {
            //If location is not present in the string the loop will break
            break
        } else {
            //This line of code colour the searched text
            attribute.addAttribute(NSAttributedStringKey.foregroundColor, value: UIColor.red , range: colorRange)
            lblContent.attributedText = attribute

            //This line of code increment the rangeString variable
            rangeString = NSMakeRange(colorRange.location + colorRange.length, contentString.length - (colorRange.location + colorRange.length))
        }
    }

The below line of code update the range by incrementing the location and length parameter of NSRange

rangeString = NSMakeRange(colorRange.location + colorRange.length, contentString.length - (colorRange.location + colorRange.length))

iOS Swift Change Particular Text Color Inside Label Programatically

1 Answers1