iOS開發進階 - 富文本正則替換表情

最近寫項目需要用到富文本解析字符串顯示表情，下面是我使用正則替換實現富文本的方式，希望能幫助到大家

先上效果圖

實現過程中需要用到的知識點

• NSRegularExpression（正則表達式）
• NSMutableAttributedString（用來顯示富文本的string）

廢話不多說，直接貼代碼：

import UIKit

struct WCLEmojiParse {

    //所有表情對應的字符串
    static let emotions = ["[angry]", "[beers]", "[blush]", "[bomb]", "[cool]", "[flushed]", "[grin]", "[gun]", "[heart]", "[heartseyes]", "[imp]", "[Joy]", "[kiss]", "[ok]", "[persevere]", "[pray]", "[punch]", "[scream]", "[shit]", "[skull]", "[sleeping]", "[smiley]", "[smirk]", "[sob]","[sweat]", "[thumbsup]", "[tongue]", "[unamused]", "[v]", "[weary]", "[wink]", "[yum]"]

    //String的格式
    static let textAttributes = [NSFontAttributeName: UIFont.systemFont(ofSize: 16), NSForegroundColorAttributeName: UIColor.black]
    //正則表達式的格式
    static let pattern = "\\[+[a-z]+\\]"
    //表情的bounds
    static let attachmentBounds = CGRect.init(origin: CGPoint.init(x: 0, y: -5), size: CGSize.init(width: 24, height: 24))

    //MARK: Public Methods
    static func replaceEmoji(_ str: String) -> NSAttributedString {
        //轉成NSString
        let originalNSString = str as NSString
        //通過str獲得NSMutableAttributedString
        let attStr = NSMutableAttributedString.init(string: str, attributes: textAttributes)
        var regex: NSRegularExpression?
        do {
            regex = try NSRegularExpression.init(pattern: pattern, options: .caseInsensitive)
        } catch let error as NSError {
            print(error.localizedDescription)
        }
        //獲取到匹配正則的數據
        if let matches = regex?.matches(in: str, options: .withoutAnchoringBounds, range: NSMakeRange(0,attStr.string.characters.count)) {
            if matches.count > 0 {
                //遍歷符合的數據進行解析
                for i in 0..<matches.count {
                    let result = matches[matches.count-i-1]
                    let range = result.range
                    let emojiStr = originalNSString.substring(with: range)
                    //符合的數據是否為表情
                    if emotions.contains(emojiStr) {
                        if let image = UIImage.init(named: emojiStr) {
                            //創建一個NSTextAttachment
                            let attachment    = NSTextAttachment()
                            attachment.image  = image
                            attachment.bounds = attachmentBounds
                            //通過NSTextAttachment生成一個NSAttributedString
                            let rep = NSAttributedString(attachment: attachment)
                            //把表情于之前的字符串替換
                            attStr.replaceCharacters(in: range, with: rep)
                        }
                    }
                }
            }
        }
        return attStr
    }
}

以上是簡單的富文本顯示表情的方式，拋磚引玉，大家見笑了，希望大家能學到東西。

來自：http://imwcl.com/2016/11/28/iOS開發進階-富文本正則替換表情/