Swift 中的项目符号列表 - iOS

Posted 2023-03-14

【中文标题】Swift 中的项目符号列表 - iOS

【英文标题】：Bulleted list in Swift - iOS

【发布时间】：2018-07-18 12:23:49

【问题描述】：

我需要在 ios 应用程序的 textView 中添加项目符号文本。我正在查看this link 和this one 并遵循他们的想法。这是我的代码：

let paragraph = NSMutableParagraphStyle()
paragraph.firstLineHeadIndent = 15
paragraph.headIndent = 15

attributes = [
    NSAttributedStringKey.paragraphStyle: paragraph
]

attributedString = NSAttributedString(string: "\u2022 Some text some text some text some text some text some text", attributes: attributes)
finalText.append(attributedString)

我需要的是让文本以上面 text 的开头缩进。和图片一样：

我得到的是与 bullet 的起点缩进的文本。

【问题讨论】：

你可能想要使用段落的 indention 来达到你想要的效果，所以你可以开始例如这里：developer.apple.com/library/archive/documentation/Cocoa/…，然后可以继续，例如这里：developer.apple.com/documentation/uikit/nsparagraphstyle，在这两个之后，整个概念应该在你面前。

在 textView 中使用 html 段落并启用属性文本。

【参考方案1】：

从代码中删除 paragraph.firstLineHeadIndent = 15...

let paragraph = NSMutableParagraphStyle()
paragraph.headIndent = 15

attributes = [
    NSAttributedStringKey.paragraphStyle: paragraph
]

attributedString = NSAttributedString(string: "\u2022 Some text some text some text some text some text some text", attributes: attributes)
finalText.append(attributedString)

请参考我的示例代码和截图

let style = NSMutableParagraphStyle()
        style.alignment = .left
        style.headIndent = 20

        let title = NSMutableAttributedString(string: "\u2022 I need to add bulleted text to textView in iOS app. I am looking at this link and this one and following their ideas. This is my code:", attributes: [NSAttributedStringKey.paragraphStyle: style,NSAttributedStringKey.foregroundColor:UIColor.blue])

        let titleStr = NSMutableAttributedString(string: "\n\n\u2022 I need to add bulleted text to textView in iOS app. I am looking at this link and this one and following their ideas. This is my code:", attributes: [NSAttributedStringKey.paragraphStyle: style,NSAttributedStringKey.foregroundColor:UIColor.blue])
        title.append(titleStr)
        titleLabel.attributedText = title

【参考方案2】：

我在textView 上遇到了同样的问题，我使用了自定义缩进并且工作正常-

 @IBOutlet  var bulletTextView: UITextView!

 override func viewDidLoad() 
        let bullet1 = "This is a small string,This is a small string,This is a small string,This is a small string,This is a small string,This is a small string,This is a small string"
        let bullet2 = "This is more of medium string with a few more words etc."
        let bullet3 = "Well this is certainly a longer string, with many more words than either of the previuos two strings"
        strings = [bullet1, bullet2, bullet3]
        let fullAttributedString = NSMutableAttributedString()
        for string: String in strings 
            let attributesDictionary:[NSAttributedStringKey:Any] = [NSAttributedStringKey.font : bulletTextView.font,NSAttributedStringKey.foregroundColor : UIColor.red]
            let bulletPoint: String = "\u2022"
            //let formattedString: String = "\(bulletPoint) \(string)\n"
            let attributedString = NSMutableAttributedString(string: bulletPoint, attributes: attributesDictionary)
            attributedString.append(NSAttributedString(string: " \(string) \n"))
            let indent:CGFloat = 15
            let paragraphStyle = createParagraphAttribute(tabStopLocation: indent, defaultTabInterval: indent, firstLineHeadIndent: indent - 10, headIndent: indent)
            attributedString.addAttributes([NSAttributedStringKey.paragraphStyle: paragraphStyle], range: NSMakeRange(0, attributedString.length))
            fullAttributedString.append(attributedString)
        
        bulletTextView.attributedText = fullAttributedString
    

    func createParagraphAttribute(tabStopLocation:CGFloat, defaultTabInterval:CGFloat, firstLineHeadIndent:CGFloat, headIndent:CGFloat) -> NSParagraphStyle 
        let paragraphStyle: NSMutableParagraphStyle = NSParagraphStyle.default.mutableCopy() as! NSMutableParagraphStyle
        let options:[NSTextTab.OptionKey:Any] = [:]
        paragraphStyle.tabStops = [NSTextTab(textAlignment: .left, location: tabStopLocation, options: options)]
        paragraphStyle.defaultTabInterval = defaultTabInterval
        paragraphStyle.firstLineHeadIndent = firstLineHeadIndent
        paragraphStyle.headIndent = headIndent
        return paragraphStyle
    

输出：-

【参考方案3】：

将paragraph.firstLineHeadIndent 设置为零。这只会缩进从第二个开始的行。目前，您正在缩进所有行……

let paragraph = NSMutableParagraphStyle()
// paragraph.firstLineHeadIndent = 15
paragraph.headIndent = 15

【讨论】：

简单的方法。

你是对的，谢谢。尽管如此，我仍然没有得到所需的缩进。现在将 firstLineHeadIndent 设置为 5 就可以了。

firstLineHeadIndent = 0 是您链接的示例中使用的内容。

【参考方案4】：

要使用动态字体调整 headIndent 的大小，我正在使用这个：

private func updateUI() 
    let bullet: NSString = "• "
    var attributes = [NSAttributedString.Key: Any]()
    let paragraph = NSMutableParagraphStyle()
    leStackView.subviews.compactMap( $0 as? UILabel ).forEach 
        attributes[.font] = $0.font
        paragraph.headIndent = bullet.size(withAttributes: attributes).width
        attributes[.paragraphStyle] = paragraph
        let text = $0.text ?? ""
        $0.attributedText = NSAttributedString(string: text, attributes: attributes)
    

每个项目符号点的标签在情节提要中设置为纯文本（包括项目符号）和动态字体。

我非常感谢对这个帖子的贡献以及https://bendodson.com/weblog/2018/08/09/bulleted-lists-with-uilabel/

【参考方案5】：

简单的解决方案：

extension Sequence where Self.Element == String 

  func toBulletList(_ bulletIndicator: String = "•",
                    itemSeparator: String = "\n",
                    spaceCount: Int = 2) -> String 
    let bullet = bulletIndicator + String(repeating: " ", count: spaceCount)
    let list = self
      .map  bullet + $0 
      .reduce("",  $0 + ($0.isEmpty ? $0 : itemSeparator) + $1 )
    return list
  

用法：

let items: [String] = [
"one",
"two",
"three"
]

let list = items.toBulletList()

po list -> 
    •  one
    •  two
    •  three

【参考方案6】：

我遇到了同样的问题，我终于意识到Label 不支持它。如果你想在同一行中使用子弹列表，你应该使用text view