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NSAttribute字符串项目符号列表问题

nsattributedstring uitextview swift ios

devforfu · 技术社区 · 8 年前

我正在尝试使用创建项目符号列表 NSAttributedString UITextView . 以下是我迄今为止所取得的成就:

正如人们所看到的,在两条线之间有一个小的“转变”。下面是我用来构建属性字符串的代码片段:

func add(bulletList strings: [String],
         indentation: CGFloat = 15,
         lineSpacing: CGFloat = 3,
         paragraphSpacing: CGFloat = 10) {

    func createParagraphAttirbute() -> NSParagraphStyle {
        var paragraphStyle: NSMutableParagraphStyle
        let nonOptions = NSDictionary() as! [NSTextTab.OptionKey: Any]

        paragraphStyle = NSParagraphStyle.default.mutableCopy() as! NSMutableParagraphStyle
        paragraphStyle.tabStops = [
            NSTextTab(textAlignment: .left, location: indentation, options: nonOptions)]
        paragraphStyle.defaultTabInterval = indentation
        paragraphStyle.firstLineHeadIndent = 0
        paragraphStyle.lineSpacing = lineSpacing
        paragraphStyle.paragraphSpacing = paragraphSpacing
        paragraphStyle.headIndent = indentation
        return paragraphStyle
    }

    var buffer = NSMutableAttributedString.init()

    for string in strings {
        let formattedString = "\u{2022} \(string)\n"
        let attributedString = NSMutableAttributedString(string: formattedString)
        let paragraphStyle = createParagraphAttirbute()

        attributedString.addAttributes(
            [NSAttributedStringKey.paragraphStyle : paragraphStyle],
            range: NSMakeRange(0, attributedString.length))

        attributedString.addAttributes(
            textAttributes,
            range: NSMakeRange(0, attributedString.length))

        let string:NSString = NSString(string: formattedString)
        let rangeForBullet:NSRange = string.range(of: bulletPoint)
        attributedString.addAttributes(bulletAttirbutes, range: rangeForBullet)
        buffer.append(attributedString)
    }
}

更新1

根据@the4kman的建议,我更改了提供的代码,如下所示:

paragraphStyle.firstLineHeadIndent = indentation

更新2

好的,解决方案很简单-用tab替换空格。请参阅下面的更新代码。

2 回复 | 直到 8 年前

devforfu 8 年前

@这位4kman,@Krunal,谢谢你的回复!解决方案甚至更简单。将空格符号替换为 \t let formattedString = "\u{2022} \(string)\n 提供有效缩进。

为了完整起见,完整的解决方案代码是(只替换一个字符):

func add(bulletList strings: [String],
         font: UIFont,
         indentation: CGFloat = 15,
         lineSpacing: CGFloat = 3,
         paragraphSpacing: CGFloat = 10,
         textColor: UIColor = .black,
         bulletColor: UIColor = .red) -> NSAttributedString {

    func createParagraphAttirbute() -> NSParagraphStyle {
        var paragraphStyle: NSMutableParagraphStyle
        let nonOptions = NSDictionary() as! [NSTextTab.OptionKey: Any]

        paragraphStyle = NSParagraphStyle.default.mutableCopy() as! NSMutableParagraphStyle
        paragraphStyle.tabStops = [
            NSTextTab(textAlignment: .left, location: indentation, options: nonOptions)]
        paragraphStyle.defaultTabInterval = indentation
        paragraphStyle.firstLineHeadIndent = 0
        paragraphStyle.lineSpacing = lineSpacing
        paragraphStyle.paragraphSpacing = paragraphSpacing
        paragraphStyle.headIndent = indentation
        return paragraphStyle
    }

    let bulletPoint = "\u{2022}"
    let textAttributes: [NSAttributedStringKey: Any] = [.font: font, .foregroundColor: textColor]
    let bulletAttributes: [NSAttributedStringKey: Any] = [.font: font, .foregroundColor: bulletColor]
    let buffer = NSMutableAttributedString.init()

    for string in strings {
        let formattedString = "\(bulletPoint)\t\(string)\n"
        let attributedString = NSMutableAttributedString(string: formattedString)
        let paragraphStyle = createParagraphAttirbute()

        attributedString.addAttributes(
            [NSAttributedStringKey.paragraphStyle : paragraphStyle],
            range: NSMakeRange(0, attributedString.length))

        attributedString.addAttributes(
            textAttributes,
            range: NSMakeRange(0, attributedString.length))

        let string:NSString = NSString(string: formattedString)
        let rangeForBullet:NSRange = string.range(of: bulletPoint)
        attributedString.addAttributes(bulletAttributes, range: rangeForBullet)
        buffer.append(attributedString)
    }

    return buffer
}

zeroimpl 7 年前

下面是一个简单的Objective-C代码片段,主要基于公认的答案:

NSString* text = 
            "â¢\tSome text for bullet 1.\n"
            "â¢\tSome text for bullet 2.\n"
            "â¢\tSome text for bullet 3."

UIFont* bodyFont = [UIFont preferredFontForTextStyle: UIFontTextStyleBody];
CGFloat indentSize = bodyFont.pointSize;
NSMutableParagraphStyle *paraStyle = [[[NSMutableParagraphStyle alloc] init];
paraStyle.alignment = NSTextAlignmentLeft;
paraStyle.tabStops = @[ [[[NSTextTab alloc] initWithTextAlignment:NSTextAlignmentLeft location:indentSize options:@{}] ];
paraStyle.defaultTabInterval = indentSize;
paraStyle.headIndent = indentSize;
paraStyle.firstLineHeadIndent = 0;
paraStyle.lineHeightMultiple = 0.85;
paraStyle.lineSpacing = 0;
paraStyle.paragraphSpacing = bodyFont.lineHeight * 0.25;
paraStyle.paragraphSpacingBefore = 0;
[atrStr appendAttributedString:
 [[[NSMutableAttributedString alloc] initWithString:avc.message attributes:@{
      NSParagraphStyleAttributeName:paraStyle,
      NSFontAttributeName: bodyFont,
  }]];