Swift 未观察到覆盖的属性

我正在创建一个游戏，我创建了一个SKScene子类，该子类应该作为其他子类的父类，这些子类将作为关卡。我初始化了SKScene类的成员变量[CGPoint]中某些块的位置和大小。后来我定义了一个函数，该函数实际创建并存储在[SKSpriteNode]类型的另一个成员变量aerialBlocks中

class GameScene: SKScene, SKPhysicsContactDelegate {
    var floatingBlockSize = [CGSize(width: 50.0, height: 10.0)]
    var floatingBlockPositions: [CGPoint] = [CGPointMake(130.0, 70.0)]

    func addPlatforms() {
        var temp = 0
        let holder = floatingBlockPositions
        for _ in floatingBlockPositions {
            floatingBlockPositions[temp].y = floatingBlockPositions[temp].y +  positionsForFirstBlock.y + (groundBlockSize.height / 2)
            let aerialBlock = SKSpriteNode(imageNamed: "aerialBlock")
            aerialBlock.size = floatingBlockSize[temp]
            aerialBlock.position = floatingBlockPositions[temp]
            print(aerialBlock.position)
            aerialBLockBody = SKPhysicsBody(rectangleOfSize: floatingBlockSize[temp])
            temp++
            aerialBlock.physicsBody = aerialBLockBody
            aerialBlock.physicsBody?.dynamic = false
            aerialBlock.physicsBody?.categoryBitMask = physicsBitMasks.aerialBlock
            aerialBlock.physicsBody?.contactTestBitMask = physicsBitMasks.player | physicsBitMasks.rollingEnemy | physicsBitMasks.walkingEnemy
            aerialBlock.physicsBody?.collisionBitMask = physicsBitMasks.player | physicsBitMasks.rollingEnemy | physicsBitMasks.walkingEnemy
            addChild(aerialBlock)
            aerialBlock.name = "aerialBlock" + String(temp)
            aerialBlocks.append(aerialBlock)
        }
        floatingBlockPositions = holder
    }
}

然后在子类中，我尝试覆盖这两个向量参数，更改其中存储的大小和值

class StreetFight: GameScene {
override var floatingBlockSize: [CGSize] {
        get {
            return [CGSize(width: 50.0, height: 10.0), CGSize(width: 150.0, height: 10.0)]
        }
        set (newValue) {
            newValue
        }
    }
    override var floatingBlockPositions: [CGPoint] {
        get {
            return [CGPointMake(400.0, 70.0), CGPointMake(250.0, 95.0)]
        }
        set (newValue) {
            newValue
        }
    }
}

我依靠父addPlatforms（）方法来解释这些新数据，并相应地放置块/平台。然而，平台的位置远低于其应有的高度。切换ViewController中显示的SKView，将一个平台正确放置在父类中