如何在RTL模式下实现带图标与文本的NSAttributedString镜像显示？

我有一个UIButton，其文本是由图标（通过字体实现的NSAttributedString）和普通文本拼接成的NSAttributedString。LTR模式下图标在左、文本在右，但切换到阿拉伯语、希伯来语等RTL语言时，图标始终停在左侧，无法自动切换到右侧。

目前构建富文本的代码：

var iconText = NSAttributedString(fontName: fontName, fontSize: fontPointSize, fontValue: fontValue, color: color ?? iconColor)
let iconTextRange = NSRange(location: 0, length: iconText.count)
let iconAttrs: [NSAttributedString.Key: Any] = [.font: icon.font(pointSize: pointSize),
                                                .foregroundColor: iconColor]

if !text.isEmpty {
    iconText = "\(iconText) \(text)"
}

let attributeString = NSMutableAttributedString(string: iconText, attributes: textAttrs)
attributeString.addAttributes(iconAttrs, range: iconTextRange)
return attributeString

之前在其他场景用以下方法实现RTL适配，但此处无效：

public extension NSAttributedString {
    /// Returns an identical attributed string that'll adjust its direction based on the device's configured language.
    func rightToLeftAdjusted() -> NSAttributedString {
        let paragraphStyle = NSMutableParagraphStyle()
        paragraphStyle.baseWritingDirection = .natural
        
        let attrs: [NSAttributedString.Key: Any] = [.paragraphStyle: paragraphStyle]
        let range = NSRange(location: 0, length: length)
        
        let copy = NSMutableAttributedString(attributedString: self)
        copy.addAttributes(attrs, range: range)
        
        return copy
    }
}

方法1：根据系统布局方向动态调整拼接顺序 #

直接判断当前系统的布局方向，从根源上改变图标和文本的拼接顺序，这是最可靠的方案：

var iconText = NSAttributedString(fontName: fontName, fontSize: fontPointSize, fontValue: fontValue, color: color ?? iconColor)
let iconAttrs: [NSAttributedString.Key: Any] = [.font: icon.font(pointSize: pointSize),
                                                .foregroundColor: iconColor]

let attributeString = NSMutableAttributedString()
// 获取当前系统布局方向
let isRTL = UIApplication.shared.userInterfaceLayoutDirection == .rightToLeft

if !text.isEmpty {
    if isRTL {
        // RTL模式：文本在前，图标在后
        attributeString.append(NSAttributedString(string: text, attributes: textAttrs))
        attributeString.append(NSAttributedString(string: " "))
        attributeString.append(iconText)
    } else {
        // LTR模式：图标在前，文本在后
        attributeString.append(iconText)
        attributeString.append(NSAttributedString(string: " "))
        attributeString.append(NSAttributedString(string: text, attributes: textAttrs))
    }
} else {
    attributeString.append(iconText)
}

// 为图标应用样式，根据布局方向调整范围
let iconRange = isRTL ? NSRange(location: text.count + 1, length: iconText.length) : NSRange(location: 0, length: iconText.length)
attributeString.addAttributes(iconAttrs, range: iconRange)

return attributeString

方法2：利用UIButton的语义属性自动适配 #

通过设置按钮的语义属性，让按钮自动翻转内容布局，配合富文本的段落样式使用：

1. 配置按钮的语义属性：

// 让按钮跟随系统语言自动调整布局方向
button.semanticContentAttribute = .natural
// 同时确保按钮的内容对齐方式适配
button.contentHorizontalAlignment = .leading

2. 保留你现有的rightToLeftAdjusted扩展，确保富文本的段落样式正确应用。

方法3：使用Unicode控制字符强制方向 #

在字符串中插入Unicode方向控制标记，告诉系统解析文本的顺序，适合简单场景：

let isRTL = UIApplication.shared.userInterfaceLayoutDirection == .rightToLeft
// Unicode控制字符：\u{200F}强制RTL，\u{200E}强制LTR
let directionMarker = isRTL ? "\u{200F}" : "\u{200E}"

var iconText = NSAttributedString(fontName: fontName, fontSize: fontPointSize, fontValue: fontValue, color: color ?? iconColor)
let iconTextRange = NSRange(location: 0, length: iconText.count)
let iconAttrs: [NSAttributedString.Key: Any] = [.font: icon.font(pointSize: pointSize),
                                                .foregroundColor: iconColor]

if !text.isEmpty {
    if isRTL {
        iconText = "\(text) \(iconText)\(directionMarker)"
    } else {
        iconText = "\(directionMarker)\(iconText) \(text)"
    }
}

let attributeString = NSMutableAttributedString(string: iconText, attributes: textAttrs)
attributeString.addAttributes(iconAttrs, range: iconTextRange)
return attributeString

内容的提问来源于stack exchange，提问作者Avi