Swift 2:'Set <UITouch>'类型的值没有成员'anyObject'

Question

我检查了我的旧游戏,我想在Swift 2.0中更新它.当我试图修复它时,Xcode发现了一个错误.错误是类型'Set'的值在此代码行中没有成员'anyObject':

var touch:UITouch = touches.anyObject() as! UITouch

功能:

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

    self.runAction(SKAction.playSoundFileNamed("torpedo.mp3", waitForCompletion: false))

    var touch:UITouch = touches.anyObject() as! UITouch //<-- Here is Error
    var location:CGPoint = touch.locationInNode(self)

    var torpedo:SKSpriteNode = SKSpriteNode(imageNamed: "torpedo")
    torpedo.position = player.position

    torpedo.physicsBody = SKPhysicsBody(circleOfRadius: torpedo.size.width/2)
    torpedo.physicsBody!.dynamic = true
    torpedo.physicsBody!.categoryBitMask = photonTorpedoCategory
    torpedo.physicsBody!.contactTestBitMask = alienCategory
    torpedo.physicsBody!.collisionBitMask = 0
    torpedo.physicsBody!.usesPreciseCollisionDetection = true

    var offset:CGPoint = vecSub(location, b: torpedo.position)

    if (offset.y < 0){
        return

    self.addChild(torpedo)

    var direction:CGPoint = vecNormalize(offset)

    var shotLength:CGPoint = vecMult(direction, b: 1000)

    var finalDestination:CGPoint = vecAdd(shotLength, b: torpedo.position)

    let velocity = 568/1
    let moveDuration:Float = Float(self.size.width) / Float(velocity)

    var actionArray:NSMutableArray =  NSMutableArray()
    actionArray.addObject(SKAction.moveTo(finalDestination, duration: NSTimeInterval(moveDuration)))
    actionArray.addObject(SKAction.removeFromParent())

    torpedo.runAction(SKAction.sequence(actionArray))
}

那么这里要解决什么？

Answer 1

鉴于Set如下UITouch定义

touches: Set<UITouch>

您可以使用此代码检索触摸

let touch = touches.first

泛型

无需强制将检索到的元素强制转换为UITouch.事实上,现在用Objective-C编写的Apple API已经使用泛型进行了更新.这意味着,在这种情况下,您会收到Set的UITouch(不是Set的NSObject,可以从字面上包含任何对象).所以Set 已经知道所包含的元素是UITouch.

选配

将first计算出的属性不会返回Optional.事实上,如果它Set是空的,它确实返回nil.

解开元素的一种安全的好方法是

guard let touch = touches.first else {
    debugPrint("Ops, no touch found...")
    return
}

// here you can use touch