获取文本内容高度和宽度

extension NSString {

func stringWidthFont(viewLab: UILabel) -> CGSize {

if self.length < 1 {
return CGSizeMake(10, 10)
}

let size = self.boundingRectWithSize(CGSizeMake(viewLab.frame.width, CGFloat.max), options: .UsesLineFragmentOrigin, attributes: [NSFontAttributeName: viewLab.font], context: nil)

return size.size
}
}