NSTextAttachment()附加属性

Question

我想在我添加到UITextView中的一些图片上添加额外的信息。这个类是NSTextAttachment()。我需要我的图像有一些String的描述，这样应用程序就知道图像里面是什么。我如何添加这个额外的功能？是通过Extension实现的吗？

let attachment = NSTextAttachment()
attachment.image = image
attachment.bounds = CGRect(origin: .zero, size: image.size)
// Extra properties wanted
attachment.description = "add in info about what is in attachment"
attachment.moreInfo = "some more info about the attachment"

Answer 1

class EmojiTextAttachment:NSTextAttachment{    
}
private var EmotagAssociationKey:String? = nil
extension EmojiTextAttachment{

    var emoticonName:String?{
        get {return objc_getAssociatedObject(self,&EmotagAssociationKey) as? String ?? ""}
        set {objc_setAssociatedObject(self, &EmotagAssociationKey, newValue, .OBJC_ASSOCIATION_RETAIN) }
    }
}

已经有一段时间了，但我的解决方案已经出来了。扩展NSTextAttachment您可以使用objc_getAssociatedObject和objc_setAssociatedObject添加参数

在使用时，请使用EmojiTextAttachment而不是NSTextAttachment。

  let emoticon:EmojiTextAttachment = EmojiTextAttachment()
                    let image = UIImage(named: myImage) as UIImage!
                    emoticon.image = image?.resizeSelf(newWidth, newHeight)
                    emoticon.emoticonName = emoname

objc_getAssociatedObject https://developer.apple.com/documentation/objectivec/1418865-objc_getassociatedobject的文档