Swift: 给定 UILabel 的宽度拆分字符串

Question

如何根据 UILabel 的宽度拆分字符串。

str = "Here is a sample of a long string that wraps at the end of the screen three times." 

width = UIScreen.Main.Bounds.Width

预期结果

strArray = ["Here is a sample of a long", "string that wraps at the  end", "of the screen three times."]

看图：

目标是将行提取为字符串，而不是换行。

Answer 1

try below function

func getStringArrayFromLabel(in label: UILabel) -> [String] {

    /// An empty string's array
    var arrLines = [String]()

    guard let text = label.text, let font = label.font else {return arrLines}

    let rect = label.frame

    let myFont: CTFont = CTFontCreateWithName(font.fontName as CFString, font.pointSize, nil)
    let attStr = NSMutableAttributedString(string: text)
    attStr.addAttribute(kCTFontAttributeName as NSAttributedString.Key, value: myFont, range: NSRange(location: 0, length: attStr.length))

    let frameSetter: CTFramesetter = CTFramesetterCreateWithAttributedString(attStr as CFAttributedString)
    let path: CGMutablePath = CGMutablePath()
    path.addRect(CGRect(x: 0, y: 0, width: rect.size.width, height: 100000), transform: .identity)

    let frame: CTFrame = CTFramesetterCreateFrame(frameSetter, CFRangeMake(0, 0), path, nil)
    guard let lines = CTFrameGetLines(frame) as? [Any] else {return arrLines}

    for line in lines {
        let lineRef = line as! CTLine
        let lineRange: CFRange = CTLineGetStringRange(lineRef)
        let range = NSRange(location: lineRange.location, length: lineRange.length)
        let lineString: String = (text as NSString).substring(with: range)
        arrLines.append(lineString)
    }
    return arrLines
}

Answer 2

希望对您有所帮助：

    let sampleFont = UIFont.systemFont(ofSize: 15)
    let oneLineHeight = NSString(string: "aaa").boundingRect(with: .init(width: 50, height: 10000), options: .usesLineFragmentOrigin, attributes: [NSAttributedString.Key.font : sampleFont], context: nil).height

    let estimatedHeight = NSString(string: "Here is a sample of a long string that wraps at the end of the screen three times.").boundingRect(with: .init(width: UIScreen.main.bounds.width, height: 10000), options: .usesLineFragmentOrigin, attributes: [NSAttributedString.Key.font : sampleFont], context: nil).height

    let numOfLines = Int(estimatedHeight / oneLineHeight)

Swift: 给定 UILabel 的宽度拆分字符串

Swift: Split string given width of UILabel

ios

swift

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