github地址

适用需求

在UILabel中展示自定义emoji或者gif/apng动画emoji，类似QQ聊天效果

背景介绍

使用NSAttributeString和NSTextAttachment可以在UILabel中进行图文混排，因此可以把一张emoji图片设置为NSTextAttachment.image或者.data：

let testAttachment = NSTextAttachment()
testAttachment.image = UIImage(named: <#T##String#>)
let testAttributeString = NSAttributedString(attachment:testAttachment)
let testLabel = UILabel()
testLabel.attributedText = testAttributeString

但是这个方法不能展示gif等序列图动画，因此我去研究了一下大名鼎鼎的YYText，bingo！完美解决！！！而且对YYText的强大功能和简洁的代码崇拜不已。But，杀鸡焉用牛刀。因此，在参考YYText的基础上，我自己写了一个满足需求的简易的EmojiLabel。

正文

1. 从gif里面获取每一帧图片

   private func gifInfo(data: Data) -> [GifFrame] {
       let source = CGImageSourceCreateWithData(data as CFData, nil)
       let count = CGImageSourceGetCount(source!)
       if count == 1 {
           if let image = UIImage(data: data) {
               return [GifFrame(image: image, delayTime: 0)]
           } else {
               return [GifFrame(image: UIImage(), delayTime: 0)]
           }
       }
       var gifFrames = [GifFrame]()
       for i in 0..<count {
           autoreleasepool {
               let itemProperties = CGImageSourceCopyPropertiesAtIndex(source!, i, nil) as! [String: Any]
               let gifProperty = itemProperties[kCGImagePropertyGIFDictionary as String] as! [String: Any]
               let delayTimeUncalmpedProp = gifProperty[kCGImagePropertyGIFUnclampedDelayTime as String] as! Float
               
               if let cgImage = CGImageSourceCreateImageAtIndex(source!, i, nil) {
                   let image = UIImage(cgImage: cgImage)
                   let gifFrame = GifFrame(image: image, delayTime: delayTimeUncalmpedProp)
                   gifFrames.append(gifFrame)
               }
           }
       }
       return gifFrames
   }
   

2. 怎么让图片动起来？

   前面已经说过，使用NSTextAttachment可以展示图片并且可以从gif序列里面把每一帧图片取出来，再加个定时器来不断的刷新图片
   Swift tick = CADisplayLink(target: _AnimatedAttachmentWeakProxy(target: self), selector: #selector(step)) tick.add(to: RunLoop.main, forMode: RunLoopMode.defaultRunLoopMode)
Swift @objc private func step() { if index >= gifFrames.count { index = 0 } let curDelayTime = gifFrames[index].delayTime time += tick.duration self.image = gifFrames[index].image if time >= TimeInterval(curDelayTime) { time = 0 index += 1 } display?() }
Swift attachment.display = { [weak self] in self?.setNeedsDisplay() }
Swift override public var attributedText: NSAttributedString? { didSet { if let attributedText = attributedText { attributedText.enumerateAttribute(.attachment, in: NSMakeRange(0, attributedText.length), options: .reverse) { (obj, range, stop) in if let attachment = obj as? AnimatedAttachment { attachment.display = { [weak self] in self?.setNeedsDisplay() } } } } } }
   前两段代码是在AnimatedAttachment里面加一个定时器来遍历gif序列并且回调AttachmentLabel；第三段是AttachmentLabel中刷新；第四段是当AttachmentLabel的attributedText变化时向AnimatedAttachment注册回调

3. 解析收到的内容 EmoticonParser

   @objc
   func parser(text: String) -> NSAttributedString? {
       let attributeString = NSMutableAttributedString(string: text)
       do {
           var flags = [String]()
           for item in items {
               flags.append(item.flag)
           }
           if flags.isEmpty == true {
               return attributeString
           }
           let pattern = flags.joined(separator: "|")
           let regex = try NSRegularExpression(pattern: pattern, options: .caseInsensitive)
           var results = [NSTextCheckingResult]()
           regex.enumerateMatches(in: text, options: NSRegularExpression.MatchingOptions.reportProgress, range: NSMakeRange(0, text.count)) { (result, flag, stop) in
               guard let result = result else { return }
               results.append(result)
           }
           
           if results.isEmpty == true {
               return attributeString
           }
           
           for result in results.reversed() {
               autoreleasepool {
                   let fromIndex = text.index(text.startIndex, offsetBy: result.range.lowerBound)
                   let toIndex = text.index(text.startIndex, offsetBy: result.range.lowerBound + result.range.length)
                   let attachmentFlagString = text[fromIndex..<toIndex]
                   
                   for item in items {
                       if item.flag == attachmentFlagString {
                           let attachment = AnimatedAttachment()
                           attachment.contents = item.emoticon
                           attachment.bounds = CGRect(x: 0, y: 0, width: item.size.width, height: item.size.height)
                           let att = NSAttributedString(attachment: attachment)
                           attributeString.replaceCharacters(in: NSMakeRange(result.range.lowerBound, result.range.length), with: att)
                       }
                   }
               }
           }
           
           return attributeString
       } catch {
           dPrint("error: \(error)")
           return attributeString
       }
   }
   

   在这个过程中，使用正则表达式来获取text中的表情特殊符，注意：for 循环要倒叙进行否则会出现越界的问题

使用

整个的使用过程是这样的

let path = Bundle.main.path(forResource: "5@2x.apng", ofType: nil)
let data = try! Data.init(contentsOf: URL(fileURLWithPath: path!)
let path2 = Bundle.main.path(forResource: "0@2x.apng", ofType: nil)
let data2 = try! Data.init(contentsOf: URL(fileURLWithPath: path2!)
let path4 = Bundle.main.path(forResource: "Expression_1@2x.png"ofType: nil)
let data4 = try! Data.init(contentsOf: URL(fileURLWithPath: path4!)
let item1 = EmoticonItem(flag: ":0:", emoticon: data, size: CGSi(width: 50, height: 50))
let item2 = EmoticonItem(flag: ":1:", emoticon: data2)
let item4 = EmoticonItem(flag: ":3:", emoticon: data4)
let parser = EmoticonParser(items: [item1, item2, item4]
let label = AttachmentLabel(frame: CGRect(x: 30, y: 30, width: 200height: 200))
label.backgroundColor = .gray
label.numberOfLines = 0
label.lineBreakMode = .byCharWrapping
view.addSubview(label
label.parser = parser
label.text = "是的护发素电:0:话费是的咖啡机啊但是jskdfja独立开:1:发绝对是计费可拉伸的就开放"
label.textColor = .white

github地址

我的个人博客
欢迎访问www.iosprogrammer.tech

谢谢！！！