iOS SDK 系统 Bug 汇总及解决方案

• iOS 10.3

• 使用NSStrikethroughStyleAttributeName添加删除线失效

添加删除线经常用在商品原价情形下，使用NSStrikethroughStyleAttributeName添加删除线在 iOS10.3之前没什么问题，结果出来一个奇葩的版本10.3（10.3.1依然未解决这个 bug），删除线渲染不出来。
目前已知的有效解决方案如下：
方案1：（推荐）

Adding a NSBaselineOffsetAttributeName, as explained here, to the attributed string brings back the strikethrough line. Overriding drawText:in:can be slow especially on Collection View or Table View Cells.

方案2：（不推荐）

I make custom UILabel class and override drawText
function, it works for NSStrikethroughStyleAttributeName
attribute. But its not support multiple line texts in simple string
.

/// This UILabel subclass accomodates conditional fix for NSAttributedString rendering broken by Apple in iOS 10.3
final class PriceLabel: UILabel {
    override func drawText(in rect: CGRect) {
        guard let attributedText = attributedText else {
            super.drawText(in: rect)
            return
        }
        if #available(iOS 10.3, *) {
            attributedText.draw(in: rect)
        } else {
            super.drawText(in: rect)
        }
    }
}