如何在Sprite Kit中移动对象？

Question

I have this code and I am trying to write a game. I want the car to go right one lane when there is a tap on the right side of the screen and left one lane when there is a tap on the left side of the screen. I wrote a function to move the car but I don't know how to get it to work. This is my code:

 //
 //  GameScene.swift
 //  cargame
 //
 //  Created by Pranav Sharan on 3/21/17.
 //  Copyright © 2017 Pranav Sharan. All rights reserved.
 //

 import SpriteKit
 import GameplayKit

class GameScene: SKScene {



override func didMove(to view: SKView) {
    let player:SKSpriteNode = self.childNode(withName: "car") as! SKSpriteNode
}


func touchDown(atPoint pos : CGPoint) {
}

func touchMoved(toPoint pos : CGPoint) {

}

func touchUp(atPoint pos : CGPoint) {

}

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    if let touch = touches.first {
        let position = touch.location(in: self)
        print(position.x)
        print(position.y)
        if position.x < 0 {
            moveLeft(object: player)
        }
    }
}

override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
    for t in touches { self.touchMoved(toPoint: t.location(in: self)) }
}

override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
    for t in touches { self.touchUp(atPoint: t.location(in: self)) }
}

override func touchesCancelled(_ touches: Set<UITouch>, with event: UIEvent?) {
    for t in touches { self.touchUp(atPoint: t.location(in: self)) }
}


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




func moveLeft(object: SKSpriteNode){
    let move = SKAction.moveTo(x: -20, duration: 0.5)
    object.run(move)
}

}

Answer 1

Here is an example of how you can Accomplish this, Hope it helps.

     class GameScene: SKScene {

var player = SKSpriteNode()
override func didMove(to view: SKView) {

    player = SKSpriteNode(color: .purple, size: CGSize(width: 100, height: 100))
    player.position = CGPoint(x: self.frame.midX, y: self.frame.midY)
    self.addChild(player)

       }


func touchDown(atPoint position : CGPoint) {

    if position.x < self.frame.midX
    {
        let move = SKAction.moveTo(x: self.frame.minX + 200, duration: 0.3)
        player.run(move)

    } else if position.x > self.frame.midX {
    let move = SKAction.moveTo(x: self.frame.maxX - 200, duration: 0.3)
    player.run(move)
    }
}

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

    for t in touches { self.touchDown(atPoint: t.location(in: self)) }
}
}

If a touch is less than the middle of the screen, The middle of the screen defined by self.frame.midX.

Answer 2

First thing I see is that you declare your player node in the didMove() function, which makes it invisible outside the scope of that function.

Declare the player node as a property of your GameScene class to make it available everywhere inside and outside of your class. Then, you assign your scene object to it. Your code would more likely look like that:

class GameScene: SKScene {

var player:SKSpriteNode

override func didMove(to view: SKView) {
     self.player = self.childNode(withName: "car") as! SKSpriteNode
}