SKAction

Create and Run a Simple SKAction

A very simple example would be to fade out an SKSpriteNode.

In Swift:

let node = SKSpriteNode(imageNamed: "image")
let action = SKAction.fadeOutWithDuration(1.0)
node.runAction(action)

Creating a Repeating Sequence of Actions

Sometimes it is necessary to do an action on repeat or in a sequence. This example will make the node fade in and out a total of 3 times.

In Swift:

let node = SKSpriteNode(imageNamed: "image")
let actionFadeOut = SKAction.fadeOutWithDuration(1.0)
let actionFadeIn = SKAction.fadeInWithDuration(1.0)
let actionSequence = SKAction.sequence([actionFadeOut, actionFadeIn])
let actionRepeat = SKAction.repeatAction(actionSequence, count: 3)
node.runAction(actionRepeat)

Running a Block of Code in an SKAction

One helpful case is to have the action run a block of code.

In Swift:

let node = SKSpriteNode(imageNamed: "image")
let actionBlock = SKAction.runBlock({
    //Do what you want here
    if let gameScene = node.scene as? GameScene {
        gameScene.score += 5
    }
})
node.runAction(actionBlock)

Named actions that can be started or removed from elsewhere.

Sometimes you would want to start or remove an action on a specific node at a certain time. For example, you might want to stop a moving object when the user taps the screen. This becomes very helpful when a node has multiple actions and you only wants to access one of them.

let move = SKAction.moveTo(x: 200, duration: 2)
object.run(move, withKey: "moveX")

Here we set the key “moveX” for the action move in order to access it later in another part of the class.

  override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        object.removeAction(forKey: "moveX")
    }

When the user touches the screen the action will get removed and the object will stop moving.