1、封裝label

import UIKit
class MyFlashLabel: UIView {
    var innerContainer: UIView
    //計(jì)算text長度并返回
    func evaluateContentWidth(text: String) -> CGFloat {
        var height: CGFloat = 0.0
        let options: NSStringDrawingOptions = NSStringDrawingOptions.UsesLineFragmentOrigin
        if text.characters.count > 0 {
            let attributedDic = [NSFontAttributeName : UIFont.systemFontOfSize(12.0)]
            let size: CGSize = text.boundingRectWithSize(CGSizeMake(self.bounds.size.width - 20,CGFloat(MAXFLOAT)), options: options, attributes:attributedDic, context: nil).size
            height = size.height
        }
        return height
    }
    
    init(frame: CGRect, text: String) {
        self.innerContainer = UIView()
        super.init(frame: frame)
        self.innerContainer = UIView(frame: self.bounds)
        self.innerContainer.backgroundColor = UIColor.clearColor()
        self.clipsToBounds = true
        self.backgroundColor = UIColor.yellowColor()
        self.addSubview(self.innerContainer)
        print(self.subviews.count)
        self.flashAnimation(text)
        
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    
    // 動畫
    func flashAnimation(text: String) {
        self.innerContainer.layer.removeAnimationForKey("move")
        let height: CGFloat = self.evaluateContentWidth(text)
        let label1: UILabel = UILabel(frame: CGRectMake(10,0,self.bounds.size.width - 10,height))
        label1.text = text
        label1.numberOfLines = 0
        label1.textColor = UIColor.greenColor()
        label1.font = UIFont.systemFontOfSize(12.0)
        label1.backgroundColor = UIColor.clearColor()
        self.innerContainer.addSubview(label1)
        
        if height > self.bounds.size.height {
            let label2: UILabel = UILabel(frame: CGRectMake(10,height + 5,self.bounds.size.width - 10,height))
            label2.text = text
            label2.numberOfLines = 0
            label2.backgroundColor = UIColor.clearColor()
            label2.font = UIFont.systemFontOfSize(12.0)
            label2.textColor = UIColor.greenColor()
            self.innerContainer.addSubview(label2)
            
            let moveAnimation: CAKeyframeAnimation = CAKeyframeAnimation(keyPath: "position.y")
            moveAnimation.keyTimes = [0.0,1.0]
            moveAnimation.duration = Double(height)/5.0
            moveAnimation.values = [0,-height - 5]
            moveAnimation.repeatCount = MAXFLOAT
            moveAnimation.timingFunction = CAMediaTimingFunction(name: "linear")
            self.innerContainer.layer.addAnimation(moveAnimation, forKey: "move")
        }
        
        
    }
}

2、添加到指定控制器

let labelView: MyFlashLabel = MyFlashLabel(frame: CGRectMake(20, 100, 280, 100), text: "\n滾動吧滾動吧滾動吧滾動吧滾動吧滾動吧滾動吧滾動吧滾動吧滾動吧滾動吧滾動吧滾動吧滾動吧滾動吧滾動吧滾動吧滾動吧滾動吧\n滾動吧滾動吧滾動吧滾動吧滾動吧滾動吧滾動吧滾動吧\n滾動吧滾動吧滾動吧滾動吧滾動吧滾動吧滾動吧滾動吧滾動吧滾動吧滾動吧滾動吧滾動吧滾動吧滾動吧滾動吧滾動吧滾動吧滾動吧")
self.view.addSubview(labelView)