SKSpriteNode .run不起作用或不起作用

Question

我试图找到以下skspritenode奇怪行为的来源：有时它只是不执行.run（...）或执行不完整。我找不到任何规律性，所以我想知道，如果这是一个已知的问题？

func didBegin(_ contact: SKPhysicsContact) {

    let firstBody = contact.bodyA
    let secondBody = contact.bodyB

 if firstBody.categoryBitMask == CollisionBitMask.birdCategory && secondBody.categoryBitMask == CollisionBitMask.BonusCategory {
        secondBody.node?.removeFromParent()
        print("contact began")
        firstBody.node?.run(SKAction.run {
            print("run works")
        })
    }
    else if firstBody.categoryBitMask == CollisionBitMask.BonusCategory && secondBody.categoryBitMask == CollisionBitMask.birdCategory {
        firstBody.node?.removeFromParent()
        print("contact began")
        secondBody.node?.run(SKAction.run {
            print("run works")
        })

    }

Answer 1

它仍然不清楚，为什么它会导致问题，但是在我尝试在代码中的某个位置设置其速度后，skspritenode没有执行.run：

enumerateChildNodes(withName: "bird", using: ({
        (node, error) in
        let bg = node as! SKSpriteNode
        bg.physicsBody?.affectedByGravity = false
       bg.speed = 0 // <- after removing this, everything works fine
        }))