SKSpritenodes子节点不会出现在自我

Question

在我的班级场景中，我有：

let health = SKSpriteNode(imageNamed: "healthBar")

当狗狗对敌人造成伤害时，我希望敌人在它上方产生一个健康栏，显示其当前的健康状况。

如果我将enemy.addChild（health）行更改为self.addChild（health），则下面的代码可以正常工作。但是当它是敌人.addChild（健康）时，健康栏是完全不可见的。我知道健康酒吧就在那里，因为我可以打印敌人。孩子们在那里展示但它不可见。有什么建议？

**注意我不能只使用self.addChild（健康），因为我需要多个健康栏跟随多个敌人位置。这就是为什么我需要每个敌人拥有自己的儿童健康栏。

if body1.categoryBitMask == PhysicsCategories.DodgingDogPlayer && body2.categoryBitMask == PhysicsCategories.Enemy{ //if the player has hit an enemy
    if dogAttacking == true{
        dogAttackAnimation.position = CGPoint(x: dodgingDogPlayer.position.x, y: dodgingDogPlayer.position.y + 80)
        dogAttackAnimating()
        let waitToFade = SKAction.wait(forDuration: 0.5)
        let fadeOutSequence = SKAction.sequence([waitToFade, fadeOut])

        dogAttackAnimation.run(fadeOutSequence)
        if body2.node?.name == "Orange Cat" || body2.node?.name == "Brown Cat" || body2.node?.name == "Black Cat"{

            if ( body2.node?.childNode(withName: "health") != nil) {

                print ("already has health")
                if let enemy = contact.bodyB.node as? Enemy{

                    health.xScale = CGFloat(fixedHealthBarLength * CGFloat(enemy.healthStat))
                    health.position = CGPoint(x: enemy.position.x, y: enemy.position.y + 50)
                    health.texture?.filteringMode = SKTextureFilteringMode.nearest

                    enemy.healthStat -= 1
                    if enemy.healthStat <= 0{
                        body2.node?.removeFromParent()
                    }
                }

            } else if ( body2.node?.childNode(withName: "health") == nil) {

                print ("doesnt have health")
                health.yScale = 2
                health.zPosition = 10
                health.name = "health"
                if let enemy = contact.bodyB.node as? Enemy{

                    health.anchorPoint = CGPoint(x: 0.5, y: 0)
                    health.xScale = CGFloat(fixedHealthBarLength * CGFloat(enemy.healthStat))
                    health.position = CGPoint(x: enemy.position.x, y: enemy.position.y + 50)
                    health.alpha = 1
                    health.texture?.filteringMode = SKTextureFilteringMode.nearest
                    enemy.addChild(health)

                    enemy.healthStat -= 1
                    if enemy.healthStat <= 0{
                        body2.node?.removeFromParent()
                    }
                }

            }
        }
    }