DAMO开发者矩阵

这主要针对是 cell上label自适应高度，

let lineSpaceKey = "lineSpaceKey"

extension UILabel{

    var lineSpace :CGFloat?{

        set{

            objc_setAssociatedObject(self, lineSpaceKey, newValue, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)

        }

        get{

            return (objc_getAssociatedObject(self, lineSpaceKey) as? CGFloat)

        }

    }

    //label 内容行数  这的size 是label 的宽和高  lineSpace 是行间距

    func textNumLinesWithHeight(size:CGSize) -> CGFloat {

        let paragraphStyle = NSMutableParagraphStyle()

        paragraphStyle.lineBreakMode = self.lineBreakMode

        paragraphStyle.alignment = self.textAlignment

        

        if self.lineSpace == nil {

            self.lineSpace = 0

        }

        paragraphStyle.lineSpacing = self.lineSpace!

        let attributes = [NSFontAttributeName : self.font,

            NSParagraphStyleAttributeName : paragraphStyle];

        let contentSize = self.text!.boundingRectWithSize(size, options: [.UsesFontLeading,.UsesLineFragmentOrigin] , attributes: attributes, context: nil).size

        let labelNumber = contentSize.height / self.font.lineHeight

        return labelNumber

    }

}