ios - [NSConcreteTextStorage 属性 :atIndex:effectiveRange:]: Range or index out of bounds error in NSMutableAttributedString

Question

我正在尝试创建一个属性字符串，其中在字符串末尾附加了一个链接:

func addMoreAndLessFunctionality (textView:UITextView){
        if textView.text.characters.count >= 120
        {
            let lengthOfString = 255
            var abc : String =  (somelongStringInitiallyAvailable as NSString).substringWithRange(NSRange(location: 0, length: lengthOfString))
            abc += " ...More"
            textView.text = abc
            let attribs = [NSForegroundColorAttributeName: StyleKit.appDescriptionColor, NSFontAttributeName: StyleKit.appDescriptionFont]
            let attributedString: NSMutableAttributedString = NSMutableAttributedString(string: abc, attributes: attribs)


            attributedString.addAttribute(NSLinkAttributeName, value: " ...More", range: NSRange(location:255, length: 8))

          textView.attributedText = attributedString
            textView.textContainer.maximumNumberOfLines = 3;

        }
}

我想在这里实现的是，如果 TextView 文本中的字符超过 255，它应该在 TextView 中显示可点击的“...更多”链接，点击我已经能够获得委托(delegate)“shouldInteractWithUrl”调用，我在其中增加了 TextView 中的行数，并将链接文本更改为“...更少”。点击 Less 我再次调用相同的方法，以便它可以再次截断。 :

    func textView(textView: UITextView, shouldInteractWithURL URL: NSURL, inRange characterRange: NSRange) -> Bool
{
    print("textview should interact with URl")

    let textTapped = textView.text[textView.text.startIndex.advancedBy(characterRange.location)..<textView.text.endIndex]

    if textTapped == " ...More"{

        var abc : String =  (self.contentDetailItemManaged?.whatsnewDesc)!
        abc += " ...Less"
        textView.textContainer.maximumNumberOfLines = 0
        let attribs = [NSForegroundColorAttributeName: StyleKit.appDescriptionColor, NSFontAttributeName: StyleKit.appDescriptionFont]
        let attributedString: NSMutableAttributedString = NSMutableAttributedString(string: abc, attributes: attribs)
        attributedString.addAttribute(NSLinkAttributeName, value: " ...Less", range: NSRange(location:abc.characters.count-8 , length: 8))

        textView.attributedText = attributedString


    }
    else if textTapped == " ...Less"{

        textView.attributedText = nil
        textView.text = somelongStringInitiallyAvailable
        self.addMoreAndLessFunctionality(textView)
    }

    return true
}

现在的问题是，当第一次调用第一个方法时(它是在我设置了 textview 的文本之后调用的)，它工作正常，但是在点击“...更多”之后，textview 正常扩展，“...更多”更改为“...更少”。当点击“...Less”时，它会崩溃并发生异常:

[NSConcreteTextStorage attribute:atIndex:effectiveRange:]: Range or index out of bounds'

任何帮助将不胜感激。 (另外，字符串“...More”的开头有一个空格，所以总共有 8 个字符，我可能在输入上面的代码时漏掉了这个空格)

谢谢:)

Answer 1

在 func textView(textView: UITextView, shouldInteractWithURL URL: NSURL, inRange characterRange: NSRange) -> Bool

中返回 false