Localizing SKLabelNodes in .sks files

Most of my first scenes I implemented by code instead of the GUI tool, but eventually I thought it could be quite helpful for certain scenes.

I quickly noticed the issue that it was not so straightforward to localize the SKLabelNode texts anymore.

I tried the default method by clicking ‘Localize…’ button in the tool, but that actually made duplicates of the .sks file that I was supposed to change for localizing the texts. This seemed to have the bad side that if I were to make changes to the layout or add new elements, I would have to do it multiple times.

Instead I implemented this bit of code where I unarchive the .sks files. This is what the default unarchive function more or less looks like:

extension SKNode {
    class func unarchiveFromFile(file : NSString) -> SKNode? {

        let path = NSBundle.mainBundle().pathForResource(file, ofType: "sks")

        var sceneData = NSData.dataWithContentsOfFile(path!, options: .DataReadingMappedIfSafe, error: nil)
        var archiver = NSKeyedUnarchiver(forReadingWithData: sceneData)

        archiver.setClass(self.classForKeyedUnarchiver(), forClassName: "SKScene")
        let scene = archiver.decodeObjectForKey(NSKeyedArchiveRootObjectKey) as SKScene
        archiver.finishDecoding()
        scene.scaleMode = .AspectFill
        localizeLabelNodes(scene)
        return scene
    }
}

For this article the interesting bit is the call to localizeLabelNodes. There I do this:

func localizeLabelNodes(scene : SKScene)
{
    for node in scene.children
    {
        if var labelNodeText = (node as? SKLabelNode)?.text
        {
            var index = advance(labelNodeText.startIndex, 4)
            if labelNodeText.substringToIndex(index) == "L:::"
            {
                var langId = labelNodeText.substringFromIndex(index)
                (node as? SKLabelNode)?.text = NSLocalizedString(langId, comment: langId)
            }
        }
    }
}

So basically I enumerate the SKLabelNodes of the scene, and if the text matches the pattern “L:::”, I know that this is something to localize. Then I simply the substring as the translation ID.

Example:
In .sks file, SKLabelNode.text : “L:::New Game”
In localizable.strings (English): “New Game” = “New Game”;
In localizable.strings (Finnish): “New Game” = “Uusi Peli”;

This way when I want to change translations of .sks SKLabelNodes, I can segregate changes to the strings file like elsewhere.