Question

我试图使用UITextView的第一行设置我的笔记的标题。只有我的代码的最后一部分不起作用。

（如果您想知道为什么我使用＆＃34;否则＆＃34;除了30个字符的声明之外，因为如果我不放入注意至少30个字符，这是一个错误）

 override func viewWillDisappear(animated: Bool) {
        detailItem!.noteText = self.textView.text


        if !self.textView.text.isEmpty {
            var textViewString:String = self.textView.text

            if let range = self.textView.text.rangeOfString("\n") {
                let rangeOfString = self.textView.text.startIndex ..< range.endIndex
                let firstLine = self.textView.text.substringWithRange(rangeOfString)

                detailItem?.noteTitle = firstLine
            } else {
                // take up to the first 30 characters as the title
                let length = count(self.textView.text)
                if length > 30 {
                    let firstLine = (textView.text as NSString).substringFromIndex(30)
                    detailItem?.noteTitle = firstLine
                } else {
                    let firstLine = (textView.text as NSString).substringFromIndex(length)
                    detailItem?.noteTitle = firstLine
                }
            }
        }

所以不起作用的代码就是最后一部分：

                    } else {
                        let firstLine = (textView.text as NSString).substringFromIndex(length)
                        detailItem?.noteTitle = firstLine
                    }

问题：

1）普通旧int和变量是什么区别？

2）如果我的方法不可能，那么实现相同结果的工作是什么？

Answer 1

使用.substringToIndex（）而不是.substringFromIndex（），然后您将获得正确的结果。

Answer 2

我有同样的问题，我发现这种方式非常有效。您在代码注释中有解释：

//If it's empty will return this values

    if self.txtText.text.isEmpty {

        title = "(Empty Note)"
        texto = "(Empty Note)"
    }

    //If it's not...
    else
    {
        //We provide the value "\n" to say which will be te last character
        let till: Character = "\n"
        if let idx = texto.characters.indexOf(till) {

        //Get the position of this character
            let pos = texto.startIndex.distanceTo(idx)

        //Substract 1 to not add the \n to the title
            firstLine = (txtText.text as NSString).substringToIndex(pos-1)
        }
        else {

            //If it's longer than 30 chars, get 30
            if texto.characters.count >= 30{
                firstLine = (txtText.text as NSString).substringToIndex(30)
            }

            //If it's shorter, count the chars and get till the last of this line
            else{
                firstLine = (txtText.text as NSString).substringToIndex(texto.characters.count)
            }
        }
        title = firstLine
    }

从UITextView的第一行创建标题（Think Apple Notes应用程序）Swift

2 个答案: