ios - 平衡多行 UILabel

Question

当我创建一个 UILabel 并将 textAlignement 设置为 NSTextAlignmentCenter 时，lineBreakMode 为 NSLineBreakByWordWrapping 和一个长文本，它像这样拆分:

+------------------------------------+
| Text that does not fit on a single |
|                line                |
+------------------------------------+

但我真正想要的是这样的:

+------------------------------------+
|       Text that does not fit       |
|          on a single line          |
+------------------------------------+

当然，我不想手动处理换行符。我希望标签自动平衡线条，使它们的长度尽可能接近。

Answer 1

我在 Swift 3 (iOS 10) 中工作，所以我转换了 dev_jac对有需要的人的回答:

override func drawText(in rect: CGRect) {
    var newRect = rect

    if (textAlignment == .center) {
        let oneLineRect = self.textRect(forBounds: CGRect.infinite, limitedToNumberOfLines: 1)
        let numLines = ceil(oneLineRect.size.width / self.bounds.size.width)
        var betterWidth : CGFloat = oneLineRect.size.width / numLines
        if (betterWidth < rect.size.width) {
            var check = CGRect.zero
            repeat {
                betterWidth *= 1.1
                let b = CGRect(x: 0, y: 0, width: betterWidth, height: CGRect.infinite.size.height)
                check = self.textRect(forBounds: b, limitedToNumberOfLines: 0)
            } while (check.size.height > rect.size.height && betterWidth < rect.size.width)

            if betterWidth < rect.size.width {
                let difference : CGFloat = rect.size.width - betterWidth
                newRect = CGRect(x: rect.origin.x + difference/2, y: rect.origin.y, width: betterWidth, height: rect.size.height)
            }
        }
    }

    super.drawText(in: newRect)
}