AnimationLabel.swift

import UIKit
import XCPlayground


enum AnimatedTextUpdate {
    
    case up
    case down
    case left
    case right
    
}

class AnimationLabel : UIView {
    
    var labelOne : UILabel
    var labelTwo : UILabel
    
    // reference to labelOne and labelTwo that is based on visibility
    private weak var visibleLabel : UILabel!
    private weak var inVisibleLabel : UILabel!
    
    // implement all needed label attributes in a similar fashion
    var numberOfLines : Int {
        get {
            return visibleLabel.numberOfLines
        }
        set(value) {
            visibleLabel.numberOfLines = value
            inVisibleLabel.numberOfLines = value
        }
    }
    
    var text : String? {
        get {
            return visibleLabel.text
        }
        set(value) {
            visibleLabel.text = value
        }
    }
    
    override init(frame: CGRect) {
        
        labelOne = UILabel(frame: CGRect(origin: CGPointZero, size: frame.size))
        labelTwo = UILabel(frame: CGRect(origin: CGPoint(x: 0, y: frame.size.height), size: frame.size))
        
        super.init(frame: frame)
        
        labelOne.textAlignment = NSTextAlignment.Center
        labelTwo.textAlignment = NSTextAlignment.Center
        
        visibleLabel = labelOne
        inVisibleLabel = labelTwo
        
        self.addSubview(labelOne)
        self.addSubview(labelTwo)
        
        // hide stuff that is outside of the frame
        self.clipsToBounds = true
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    func updateTextAnimated(text updateText:String,animation: AnimatedTextUpdate,duration:Double) {
        
        // late init of points
        let invisibleOrigin : CGPoint
        let invisibleDestination : CGPoint = CGPointZero
        let visibleDestination : CGPoint
        
        // switch the animation
        switch animation {
        case .down :
            invisibleOrigin = CGPoint(x: 0, y: -visibleLabel.frame.size.height)
            visibleDestination = CGPoint(x: 0, y: visibleLabel.frame.size.height)
        case .up :
            invisibleOrigin = CGPoint(x: 0, y: visibleLabel.frame.size.height)
            visibleDestination = CGPoint(x: 0, y: -visibleLabel.frame.size.height)
        case .right :
            invisibleOrigin = CGPoint(x: -visibleLabel.frame.size.width, y: 0)
            visibleDestination = CGPoint(x: visibleLabel.frame.size.width, y: 0)
        case .left :
            invisibleOrigin = CGPoint(x: visibleLabel.frame.size.width, y: 0)
            visibleDestination = CGPoint(x: -visibleLabel.frame.size.width, y: 0)
        }
        
        // set correct start position and set text
        inVisibleLabel.frame.origin = invisibleOrigin
        inVisibleLabel.text = updateText
        
        // animate
        UIView.animateWithDuration(duration) { () -> Void in
            self.visibleLabel.frame.origin = visibleDestination
            self.inVisibleLabel.frame.origin = invisibleDestination
        }
        
        // switch label reference
        let tempLabel = visibleLabel
        visibleLabel = inVisibleLabel
        inVisibleLabel = tempLabel
        
    }
}


var test = AnimationLabel(frame: CGRect(origin: CGPointZero, size: CGSize(width: 200, height: 50)))
test.backgroundColor = UIColor.whiteColor()

test.text = "1"
test.updateTextAnimated(text: "2", animation: .down, duration: 1.0)

XCPlaygroundPage.currentPage.liveView = test