Swift-对动态创建的UIImageView进行动画处理

Question

Initially I had this code working when I was just animating the one UIImageView that I had. But then I changed it to animate several dynamically created UIImageViews, however since they are dynamically created inside a for loop, I'm finding it difficult to animate them as I did the initial one.

override func viewDidLoad() {
    super.viewDidLoad()

    var sprite: UIImage = UIImage(named: "sprites/areaLocatorSprite.png")!

    var locations:NSArray = animal[eventData]["locations"] as NSArray

    for var i = 0; i < locations.count; i++ {

        println(locations[i]["locationx"])
        var locationx = locations[i]["locationx"] as String
        var locationy = locations[i]["locationy"] as String

        let x = NSNumberFormatter().numberFromString(locationx)
        let y = NSNumberFormatter().numberFromString(locationy)
        let cgfloatx = CGFloat(x!)
        let cgfloaty = CGFloat(y!)

        var mapSprite: UIImageView
        mapSprite = UIImageView(image: sprite)

        mapSprite.frame = CGRectMake(cgfloatx,cgfloaty,10,10)
        townMap.addSubview(mapSprite)

        timer = NSTimer.scheduledTimerWithTimeInterval(0.35, target: self, selector: Selector("flash"), userInfo: nil, repeats: true)

    }

}

func flash() {
    var mapSprite:UIImageView?

    if mapSprite?.alpha == 1 {
        mapSprite?.alpha = 0
    } else {
        mapSprite?.alpha = 1
    }
}

This does not work as the mapSprite in the flash function is different to the one in the for loop. How can I refer to the one in the for loop and then animate it? Or would there be a better alternative to what I'm currently doing?

Many thanks!

EDIT Using Xcode 6.2

Answer 1

You need to store the views into a property and then enumerate that property each time your timer event is fired

var sprites: [UIImageView]?

override func viewDidLoad() {
  super.viewDidLoad()

  var sprite = UIImage(named: "sprites/areaLocatorSprite.png")!

  var locations:NSArray = animal[eventData]["locations"] as NSArray

  self.sprites = map(locations) {
    var locationx = $0["locationx"] as String
    var locationy = $0["locationy"] as String

    let x = NSNumberFormatter().numberFromString(locationx)
    let y = NSNumberFormatter().numberFromString(locationy)
    let cgfloatx = CGFloat(x!)
    let cgfloaty = CGFloat(y!)

    var mapSprite = UIImageView(image: sprite)

    mapSprite.frame = CGRectMake(cgfloatx,cgfloaty,10,10)
    townMap.addSubview(mapSprite)

    return mapSprite
  }

  timer = NSTimer.scheduledTimerWithTimeInterval(0.35, target: self, selector: Selector("flash"), userInfo: nil, repeats: true)
}

func flash() {
  if let sprites = self.sprites {
    for sprite in sprites {
      sprite.alpha = sprite.alpha == 0 ? 1 : 0
    }
  }
}