Ios ContactBitMask表示我的对象发生碰撞，但它们没有'；T

我正在编写这个游戏，当猪和鱼发生碰撞时，游戏结束了。但是当我玩的时候，猪没有碰鱼，但是游戏自动结束了。我该如何解决这个问题？相关的方法有干、吃等

import SpriteKit
import GameplayKit

var totalTime = 0
class GameScene: SKScene,SKPhysicsContactDelegate {
private var label : SKLabelNode?
var flyingPig:SKSpriteNode!
var water = SKSpriteNode()
var scoreLabel :SKLabelNode!

var currentGameState = gameState.atGame



struct PhysicsCategories{
    static let None :UInt32 = 0
    static let pig : UInt32 = 0b1
    static let aFish : UInt32 = 0b100
}

var timer : Timer!
var timing : Timer!
var fish = ["nemo","bluedy","lantern","balloon","Knife"]
var myTime = 0
var lives:[SKSpriteNode]!

override func didMove(to view: SKView) {

    totalTime = 0
    self.physicsWorld.contactDelegate = self
    water = SKSpriteNode(imageNamed: "water")

    water.position = CGPoint(x: self.size.width/2,y:self.size.height/2)

    water.physicsBody = SKPhysicsBody(rectangleOf: water.size)

    water.physicsBody?.affectedByGravity = false
    water.physicsBody?.isDynamic = false

    self.addChild(water)

    flyingPig = SKSpriteNode(imageNamed:"FlyingPig")
    flyingPig.position = CGPoint(x:self.size.width/2,y:self.size.height/2)
    flyingPig.physicsBody = SKPhysicsBody(rectangleOf: flyingPig.size)
    flyingPig.physicsBody!.affectedByGravity=false
    flyingPig.physicsBody!.collisionBitMask = PhysicsCategories.None
    flyingPig.physicsBody!.categoryBitMask = PhysicsCategories.pig
    flyingPig.physicsBody!.contactTestBitMask = PhysicsCategories.aFish
    self.addChild(flyingPig)

    self.physicsWorld.gravity = CGVector(dx:0,dy:0)
    self.physicsWorld.contactDelegate = self

    scoreLabel = SKLabelNode(text:"Score: 0")
    scoreLabel.position = CGPoint(x:85,y:1270)
    scoreLabel.fontName = "PartyLetPlain"
    scoreLabel.fontSize = 44
    scoreLabel.text = "Score: \(totalTime) km"
    self.addChild(scoreLabel)

    timer = Timer.scheduledTimer(timeInterval:1.25 ,target:self,selector:#selector(addFish),userInfo:nil,repeats:true)

    timing = Timer.scheduledTimer(timeInterval: 1.5, target: self, selector: #selector(tick), userInfo: nil, repeats: true)

    addLives()
}


func addLives()
{
    lives = [SKSpriteNode()]
    for live in 1...3{
        let liveNode = SKSpriteNode(imageNamed:"FlyingPig2")
        liveNode.position = CGPoint(x:750-CGFloat(4-live)*liveNode.size.width,y:1270)
        self.addChild(liveNode)
        lives.append(liveNode)
    }
}

func addFish()
{
    fish = GKRandomSource.sharedRandom().arrayByShufflingObjects(in: fish) as![String]

    let aFish = SKSpriteNode(imageNamed: fish[0])

    let fishPosition = GKRandomDistribution(lowestValue:0, highestValue:700)
    let position = CGFloat(fishPosition.nextInt())
    aFish.position=CGPoint(x:position,y:1200)

    aFish.physicsBody = SKPhysicsBody(rectangleOf: aFish.size)
    aFish.physicsBody!.affectedByGravity = false
    aFish.physicsBody?.isDynamic=false
    aFish.physicsBody!.categoryBitMask = PhysicsCategories.aFish
    aFish.physicsBody!.collisionBitMask = PhysicsCategories.None
    aFish.physicsBody!.contactTestBitMask = PhysicsCategories.pig
    self.addChild(aFish)



    let animationDuration:TimeInterval = 12
    var actionArray = [SKAction]()
    actionArray.append(SKAction.move(to:CGPoint(x:position,y:-800),duration:animationDuration))
    aFish.run(SKAction.sequence(actionArray))
        }

func didBegin(_ contact: SKPhysicsContact) {
    var body1 = SKPhysicsBody()
    var body2 = SKPhysicsBody()

    if contact.bodyA.categoryBitMask < contact.bodyB.categoryBitMask{
        body1 = contact.bodyA
        body2 = contact.bodyB
    }
    else{
        body1 = contact.bodyB
        body2 = contact.bodyA
    }

    if body1.categoryBitMask == PhysicsCategories.pig && body2.categoryBitMask==PhysicsCategories.aFish
    {
        body2.node?.removeFromParent()
        gameOver()
    }
}

enum gameState{
    case before
    case atGame
    case after
}


func gameOver(){
    self.removeAllActions()
    currentGameState=gameState.after
    let changeSceneAction = SKAction.run(changeScene)
    let waitToChangeScene = SKAction.wait(forDuration:0.1)
    let changeSceneSequence = SKAction.sequence([waitToChangeScene,changeSceneAction])
    self.run(changeSceneSequence)



}
func changeScene(){
    let newScene = GameOverScene(size:self.size)
    newScene.scaleMode = self.scaleMode
    let transition = SKTransition.fade(withDuration: 0.1)
    self.view!.presentScene(newScene,transition:transition )

}


func touchDown(atPoint pos : CGPoint) {

}

func touchMoved(toPoint pos : CGPoint) {

}

func touchUp(atPoint pos : CGPoint) {

}

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {


    for touch in (touches ){
    let location = touch.location(in: self)
    if self.flyingPig.contains(location){
        flyingPig.position = location
        }
    }

}


override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {

    for touch in (touches ){
        let location = touch.location(in: self)
        if flyingPig.contains(location){
            flyingPig.position = location
        }
    }
}

override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {

}

override func touchesCancelled(_ touches: Set<UITouch>, with event: UIEvent?) {
       }


override func update(_ currentTime: TimeInterval) {
    // Called before each frame is rendered
}


func tick()
{
    totalTime+=1

}

导入SpriteKit
导入游戏工具包
var totalTime=0
类游戏场景：SKScene，SKPhysicContactDelegate{
私有变量标签：SKLabelNode？
var flyingPig:SKSpriteNode！
var water=SKSpriteNode（）
var scoreLabel:SKLabelNode！
var currentGameState=gameState.atGame
结构物理分类{
静态let None:UInt32=0
静态let清管器：UInt32=0b1
静态let aFish:UInt32=0b100
}
变量定时器：定时器！
var定时：定时器！
var fish=[“尼莫”、“蓝迪”、“灯笼”、“气球”、“刀”]
var myTime=0
var活着：[SKSpriteNode]！
覆盖func didMove（到视图：SKView）{
总时间=0
self.physicsWorld.contactDelegate=self
水=SKSpriteNode（图像名称：“水”）
water.position=CGPoint（x:self.size.width/2，y:self.size.height/2）
water.physicsBody=SKPhysicsBody（矩形：water.size）
水。物理体？。受重力影响=假
water.physicsBody？.isDynamic=错误
self.addChild（水）
flyingPig=SKSpriteNode（图像名为：“flyingPig”）
flyingPig.position=CGPoint（x:self.size.width/2，y:self.size.height/2）
flyingPig.physicsBody=SKPhysicsBody（矩形：flyingPig.size）
flyingPig.physicsBody！。受重力影响=false
flyingPig.physicsBody！.collisionBitMask=PhysicsCategories.None
flyingPig.physicsBody！.categoryBitMask=PhysicCategories.pig
flyingPig.physicsBody！.contactTestBitMask=PhysicsCategories.aFish
self.addChild（flyingPig）
self.physicsWorld.gravity=CGVector（dx:0，dy:0）
self.physicsWorld.contactDelegate=self
scoreLabel=SKLabelNode（文本：“分数：0”）
scoreLabel.position=CGPoint（x:85，y:1270）
scoreLabel.fontName=“PartyLetPlain”
scoreLabel.fontSize=44
scoreLabel.text=“分数：\（总时间）公里”
self.addChild（scoreLabel）
timer=timer.scheduledTimer（时间间隔：1.25，目标：self，选择器：#选择器（addFish），userInfo:nil，repeats:true）
timing=Timer.scheduledTimer（时间间隔：1.5，目标：self，选择器：#选择器（勾号），用户信息：nil，重复：true）
addlifes（）
}
func addlifes（）
{
lives=[SKSpriteNode（）]
生活在1…3{
让liveNode=SKSpriteNode（图像名为：“FlyingPig2”）
liveNode.position=CGPoint（x:750 CGFloat（4-live）*liveNode.size.width，y:1270）
self.addChild（liveNode）
lives.append（liveNode）
}
}
func addFish（）
{
fish=gkramonSource.SharedAndom（）.ArrayByShufflingObject（在：fish中）作为！[String]
设aFish=SKSpriteNode（ImageName:fish[0]）
设fishPosition=GK随机分布（最低值：0，最高值：700）
let position=CGFloat（fishPosition.nextInt（））
aFish.position=CGPoint（x:position，y:1200）
aFish.physicsBody=SKPhysicsBody（矩形：aFish.size）
aFish.physicsBody！。受重力影响=false
aFish.physicsBody？.isDynamic=false
aFish.physicsBody！.categoryBitMask=physiccategories.aFish
aFish.physicsBody！.collisionBitMask=physicCategories.None
aFish.physicsBody！.contactTestBitMask=physicCategories.pig
self.addChild（阿菲什语）
让动画持续时间：时间间隔=12
var actionArray=[SKAction]（）
actionArray.append（SKAction.move（到：CGPoint（x:position，y:-800），持续时间：animationDuration））
运行（SKAction.sequence（actionArray））
}
func didbegen（uu联系人：skphysiccontact）{
var body1=SKPhysicsBody（）
var body2=SKPhysicsBody（）
如果contact.bodyA.categoryBitMask

}

换成这个

let contactMask = bodyA.contact.categoryBitMask || bodyB.contact.categoryBitMask

switch contactMask
    case PhysicsCategories.pig ||  PhysicsCategories.aFish :
        // code
    default:
        break

let contactMask = bodyA.contact.categoryBitMask || bodyB.contact.categoryBitMask

switch contactMask
    case PhysicsCategories.pig ||  PhysicsCategories.aFish :
        // code
    default:
        break