Action not working correctly in SpriteKit - ios

Question

I'm new to iOS programing and I'm experimenting to learn trying to create a game in swift using Sprite Kit.
What I'm trying to achieve is having a constant flow of blocks being created and moving rightwards on the screen.
I start by creating a set which contains all the initial blocks, then an action "constant movement" is added to each one, which makes them move slowly to the right. What I'm having trouble is adding new blocks to the screen.
The last column of blocks has an "isLast" boolean set to true, when it passes a certain threshold it is supposed to switch to false and add a new column of blocks to the set which now have "isLast" set to true.
Each block in the set has the "constantMovement" action added which makes them move slowly to the right, the new blocks have it added as well, but they don't work as the original ones.
Not all of the move, even tho if I print "hasActions()" it says they do, and the ones that do move stop doing so when they get to the middle of the screen. I have no idea why this happens, can somebody experienced give me a hint please?
This is the update function:
override func update(currentTime: CFTimeInterval) {
/* Called before each frame is rendered */
let constantMovement = SKAction.moveByX(-1, y: 0, duration: 10);
background.runAction(SKAction.repeatActionForever(constantMovement));
let removeBlock = SKAction.removeFromParent();
let frame = self.frame;
var currentBlockSprite:SKSpriteNode;
var newBlock: Block;
for block in blocks {
currentBlockSprite = block.sprite!;
currentBlockSprite.runAction(constantMovement);
if(block.column == NumColumns - 1) {
block.isLast = true;
}
if(block.isNew) {
println("position \(currentBlockSprite.position.x) has actions \(currentBlockSprite.hasActions())");
}
if(block.isLast && currentBlockSprite.position.x < frame.maxX - 50) {
println("the block that hits is " + block.description);
println("HITS AT \(currentBlockSprite.position.x)");
block.isLast = false;
for row in 0..<NumRows {
newBlock = Block(column: NumColumns - 1, row: row, blockType: BlockType.random(), isLast: true, isNew: true);
blocks.addElement(newBlock);
addBlockSprite(newBlock);
println("new block: " + newBlock.description + "position \(newBlock.sprite?.position.x)");
}
}
if(currentBlockSprite.position.x < frame.minX) {
currentBlockSprite.runAction(removeBlock);
blocks.removeElement(block);
}
}
}
My whole project is in here: https://github.com/thanniaB/JumpingGame/tree/master/Experimenting
but keep in mind that since I'm new to this it might be full of cringeworthy bad practices.

Answer 1

I would remove any SKAction code from the update function as that's kind of a bad idea. Instead I would just apply the SKAction when you add your block sprite to the scene, like this.
func addBlockSprite(block: Block) {
let blockSprite = SKSpriteNode(imageNamed: "block");
blockSprite.position = pointForColumn(block.column, row:block.row);
if(block.blockType != BlockType.Empty) {
addChild(blockSprite);
let constantMovement = SKAction.moveByX(-10, y: 0, duration: 1)
var currentBlockSprite:SKSpriteNode
let checkPosition = SKAction.runBlock({ () -> Void in
if(blockSprite.position.x < -512){
blockSprite.removeAllActions()
blockSprite.removeFromParent()
}
})
let movementSequence = SKAction.sequence([constantMovement, checkPosition])
let constantlyCheckPosition = SKAction.repeatActionForever(movementSequence)
blockSprite.runAction(constantlyCheckPosition)
}
block.sprite = blockSprite;
}
That would then allow you to simply add a new block whenever you see fit and it will have the appropriate action when it's added.
I've used 512 as thats the size of the iPhone 5 screen but you could swap this out for another screen size or what would be better would be a variable that dynamically reflects the screen size.