将NSAttributed文本追加到UITextview [英] Append NSAttributed text to UITextview

问题描述

我不敢相信我在问这个问题，但是(一直在寻找一个半小时而没有运气的答案)... 如何将NSAttributedText附加到UITextView?(在Swift 2.0+中)

I can't believe I am asking this question but (been looking for the answer for an hour and a half with no luck)...how do I append NSAttributedText to a UITextView? (in Swift 2.0+)

我正在构建一个从服务器下载项目的工具，当它们进来时，我想添加AttributedText并添加绿色(表示成功)或添加红色(表示失败).

I'm building a tool which downloads items from my server, and as they come in I want to add AttributedText with green for success or red color for fails.

为此，我相信我需要NSMutableAttributedString，但是UITextView仅具有NSattributedString，该NSattributedString无法访问appendAttributedString(attrString: NSAttributedString NSAttributedString)

To do this I believe I need NSMutableAttributedString, but the UITextView only has NSattributedString which does not have access to the appendAttributedString(attrString: NSAttributedString NSAttributedString)

因此，如果我有一个带有NSAttributedString的UITextView，上面写着红色的正在加载"，我该如何附加带有绿色的成功"文本的正在加载"文本.

So if I have a UITextView with an NSAttributedString on it that says "loading" in red, how can I append the text "loading" with the text in green "success".

例如这样的

<font color="red">loading</font><font color="green">success</font>

更新

我找到了问题的答案，但我认为这不是最佳答案.

I found an answer to my question but I do not feel is an optimal answer.

let loadingMessage = NSMutableAttributedString(string: "loading...\n")
            loadingMessage.addAttribute(NSStrokeColorAttributeName, value: UIColor.redColor(), range: NSRange(location: 0, length: 10))

            progressWindowViewController.theTextView.attributedText = loadingMessage

loadingMessage.appendAttributedString("<font color=\"#008800\">Successfully Synced Stores...</font>\n".attributedStringFromHtml!)
                progressWindowViewController.theTextView.attributedText = loadingMessage

我上面的答案是有效的，但是可以通过覆盖整个文本来实现(并且每次绘制都会继续这样做).我想知道是否存在将字符串附加到末尾以获得最佳性能的真正方法?

My answer above works but does so by overwriting the entire text (and it will continue to do so every-time it draws). I wonder if there is a true way to append the string to the end for optimal performance?

我用于HTML的扩展名

The extension I used for HTML

extension String {

    var attributedStringFromHtml: NSAttributedString? {
        do {
            return try NSAttributedString(data: self.dataUsingEncoding(NSUTF8StringEncoding)!, options: [NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType], documentAttributes: nil)
        } catch _ {
            print("Cannot create attributed String")
        }
        return nil
    }
}

推荐答案

您可以使用mutableCopy()将NSAttributedString转换为NSMutableAttributedString，而copy()会为您做相反的事情，例如:

You can convert a NSAttributedString to a NSMutableAttributedString using mutableCopy(), and copy() will do the opposite for you, like so:

let string1 = NSAttributedString(string: "loading", attributes: [NSForegroundColorAttributeName: UIColor.redColor()])
let string2 = NSAttributedString(string: "success", attributes: [NSForegroundColorAttributeName: UIColor.greenColor()])

let newMutableString = string1.mutableCopy() as! NSMutableAttributedString
newMutableString.appendAttributedString(string2)

textView.attributedText = newMutableString.copy() as! NSAttributedString

由于mutableCopy()和copy()都返回AnyObject，所以有点尴尬，因此您需要始终使用as!将它们转换为正确的类型.

It's only a bit awkward since both mutableCopy() and copy() return AnyObject, so you'll need to convert them using as! to the correct type all the time.

这篇关于将NSAttributed文本追加到UITextview的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！