import UIKit
class ViewController3: UIViewController {override func viewDidLoad() {super.viewDidLoad()self.view.backgroundColor=UIColor.whiteColor()var scrollView = UIScrollView(frame: CGRectMake(0, 0, ScreenWidth, ScreenHeight))self.view.addSubview(scrollView)var label = UILabel(frame: CGRectMake(0,0,ScreenWidth,0))label.lineBreakMode = NSLineBreakMode.ByWordWrappinglabel.numberOfLines = 0label.text = "走过红尘的纷扰，弹落灵魂沾染的尘埃，携一抹淡淡的情怀，迎着清馨的微风，坐在岁月的源头，看时光婆娑的舞步，让自己安静在时间的沙漏里"label.font = UIFont.systemFontOfSize(14)label.textColor = UIColor.redColor()var string:NSString = label.text!let options : NSStringDrawingOptions = .UsesLineFragmentOrigin | .UsesFontLeadinglet boundingRect = string.boundingRectWithSize(CGSizeMake(ScreenWidth, 0), options: options, attributes: [NSFontAttributeName:label.font], context: nil)//var size = label.text!.sizeWithAttributes([NSFontAttributeName:label.font])label.frame = CGRectMake(0, 0, boundingRect.size.width, boundingRect.size.height)scrollView.addSubview(label)scrollView.contentSize = CGSizeMake(boundingRect.size.width, boundingRect.size.height)scrollView.backgroundColor = UIColor.cyanColor()label.backgroundColor = UIColor.blackColor()}override func didReceiveMemoryWarning() {super.didReceiveMemoryWarning()}
}

最主要的这几句

var string:NSString = label.text!let options : NSStringDrawingOptions = .UsesLineFragmentOrigin | .UsesFontLeadinglet boundingRect = string.boundingRectWithSize(CGSizeMake(ScreenWidth, 0), options: options, attributes: [NSFontAttributeName:label.font], context: nil)

boundingRect.size.width //字符串的宽，

boundingRect.size.height //字符串的高

有了宽跟高，自己折腾去吧〜！！！！