UITextView change text color of specific text

问题

I want to change the text color of a specific text within a UITextView which matches an index of an array. I was able to slightly modify this answer but unfortunatly the text color of each matching phrase is only changed once.

var chordsArray = ["Cmaj", "Bbmaj7"]
func getColoredText(textView: UITextView) -> NSMutableAttributedString {
    let text = textView.text
    let string:NSMutableAttributedString = NSMutableAttributedString(string: text)
    let words:[String] = text.componentsSeparatedByString(" ")
    for word in words {
        if (chordsArray.contains(word)) {
            let range:NSRange = (string.string as NSString).rangeOfString(word)
            string.addAttribute(NSForegroundColorAttributeName, value: UIColor.redColor(), range: range)
        }
    }
    chords.attributedText = string
    return string
}

Outcome

回答1:

Sorry, I just noticed your message. Here is a working example (tested in a playground):

import UIKit


func apply (string: NSMutableAttributedString, word: String) -> NSMutableAttributedString {
    let range = (string.string as NSString).rangeOfString(word)
    return apply(string, word: word, range: range, last: range)
}

func apply (string: NSMutableAttributedString, word: String, range: NSRange, last: NSRange) -> NSMutableAttributedString {
    if range.location != NSNotFound {
        string.addAttribute(NSForegroundColorAttributeName, value: UIColor.redColor(), range: range)
        let start = last.location + last.length
        let end = string.string.characters.count - start
        let stringRange = NSRange(location: start, length: end)
        let newRange = (string.string as NSString).rangeOfString(word, options: [], range: stringRange)
        apply(string, word: word, range: newRange, last: range)
    }
    return string
}

var chordsArray = ["Cmaj", "Bbmaj7"]
var text = "Cmaj Bbmaj7 I Love Swift Cmaj Bbmaj7 Swift"
var newText = NSMutableAttributedString(string: text)

for word in chordsArray {
    newText = apply(newText, word: word)
}

newText

回答2:

In case, someone needs it in swift 4. This is what I get from my Xcode 9 playground :).

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

        let textView = UITextView()
        textView.frame = CGRect(x: 150, y: 200, width: 200, height: 20)
        textView.text = "@Kam @Jam @Tam @Ham"
        textView.textColor = .black
        view.addSubview(textView)
        self.view = view

        let query = "@"

        if let str = textView.text {
            let text = NSMutableAttributedString(string: str)
            var searchRange = str.startIndex..<str.endIndex
            while let range = str.range(of: query, options: NSString.CompareOptions.caseInsensitive, range: searchRange) {
                text.addAttribute(NSAttributedStringKey.foregroundColor, value: UIColor.gray, range: NSRange(range, in: str))
                searchRange = range.upperBound..<searchRange.upperBound
            }
            textView.attributedText = text
        }
    }
}
PlaygroundPage.current.liveView = MyViewController()

I think for swift 3, you need to convert Range(String.Index) to NSRange manually like this.

 let start = str.distance(from: str.startIndex, to: range.lowerBound)
 let len = str.distance(from: range.lowerBound, to: range.upperBound)
 let nsrange = NSMakeRange(start, len)
 text.addAttribute(NSAttributedStringKey.foregroundColor, value: UIColor.gray, range: nsrange)

回答3:

Swift 4.2 and 5

let string = "* Your receipt photo was not clear or did not capture the entire receipt details. See our tips here.\n* Your receipt is not from an eligible grocery, convenience or club store."
let attributedString = NSMutableAttributedString.init(string: string)
let range = (string as NSString).range(of: "See our tips")
attributedString.addAttribute(NSAttributedString.Key.foregroundColor, value: UIColor.blue, range: range)
txtView.attributedText = attributedString
txtView.isUserInteractionEnabled = true
txtView.isEditable = false

Output

来源：https://stackoverflow.com/questions/33472171/uitextview-change-text-color-of-specific-text