Question

我一直在使用XCode的应用程序（版本9.3.1）并使用Coding iPhone Apps for Kids（https://nostarch.com/iphoneappsforkids/）作为指导，学习如何创建游戏，如滑板游戏从第14章开始。

我已经遵循了代码，但是使用handleTap（tapGesture :)时遇到了错误。

      override func didMove(to view: SKView) {
    physicsWorld.gravity = CGVector(dx: 0.0, dy: -6.0)
    physicsWorld.contactDelegate = self

    anchorPoint = CGPoint.zero

    let background = SKSpriteNode(imageNamed: "background")
    let xMid = frame.midX
    let yMid = frame.midY
    background.position = CGPoint(x: xMid, y: yMid)
    addChild(background)

    setupLabels()

    // Set up the player and add her to the scene
    player.setupPhysicsBody()
    addChild(player)

    // Add a tap gesture recognizer to know when the user tapped the screen
    let tapMethod = #selector(GameScene.handleTap(tapGesture:))
    let tapGesture = UITapGestureRecognizer(target: self, action: tapMethod)
    view.addGestureRecognizer(tapGesture)

    // Add a menu overlay with "Tap to play" text
    let menuBackgroundColor = UIColor.black.withAlphaComponent(0.4)
    let menuLayer = MenuLayer(color: menuBackgroundColor, size: frame.size)
    menuLayer.anchorPoint = CGPoint(x: 0.0, y: 0.0)
    menuLayer.position = CGPoint(x: 0.0, y: 0.0)
    menuLayer.zPosition = 30
    menuLayer.name = "menuLayer"
    menuLayer.display(message: "Tap to play", score: nil)
    addChild(menuLayer)
}

它在

中给出了错误

    let tapMethod = #selector(GameScene.handleTap(tapGesture:))

然而，再往下，我有这段代码。

     func handleTap(tapGesture: UITapGestureRecognizer) {

        if gameState == .running {

            // Make the player jump if player taps while she is on the ground
            if player.isOnGround {

                player.physicsBody?.applyImpulse(CGVector(dx: 0.0, dy: 260.0))

                run(SKAction.playSoundFileNamed("jump.wav", waitForCompletion: false))
            }
        }
        else {

            // If the game is not running, tapping starts a new game
            if let menuLayer: SKSpriteNode = childNode(withName: "menuLayer") as? SKSpriteNode {

                menuLayer.removeFromParent()
            }

            startGame()
        }
    }

虽然我在更新方法下有handleTap，但错误不会自行删除。

如果您对标题中的错误代码有解决方案，请告诉我们。

Answer 1

更改选择器＆amp;签名到这个

let tapMethod = #selector(GameScene.handleTap(_:))

//

@objc func handleTap(_ tapGesture: UITapGestureRecognizer) {}

Answer 2

根据docs，

在Objective-C中，选择器是一种引用名称的类型 Objective-C方法。在Swift中，Objective-C选择器由 Selector结构，可以使用#selector构造表达。为可以从中调用的方法创建选择器 Objective-C，传递方法的名称

所以我们必须通过将成员标记为@objc

来将成员暴露给obj-c

@objc func handleTap(_ tapGesture: UITapGestureRecognizer) {}

有关更多信息，请参阅：How can I deal with @objc inference deprecation with #selector() in Swift 4?

输入＆＃39; GameScene＆＃39;没有会员＆＃39; handleTap（tapGesture :)＆＃39;

2 个答案: