如何修复:按名称调用节点(由func生成)不起作用
如何修复:按名称调用节点(由func生成)不起作用
提问于 2019-06-09 22:29:10
我目前正在做我的第一个测试游戏，玩家必须跳过一些随机生成的条。我写了一个函数，它应该生成我的场景之外的条形图。我现在的问题是，当我试图用"self.childNode(withName:)“调用创建的条形图时，xCode告诉我”致命错误:在展开可选值时意外发现空“。
我已经阅读了"childNode(withName:)“的苹果文档，并在节点名称前添加了"//”。此外，我使用了stackoverflow搜索，但我找不到任何解决我的问题的东西。
//
// GameScene.swift
// PlaxerJump
//
//
import SpriteKit
import AVFoundation
class GameScene: SKScene {
let bottom1 = SKSpriteNode(imageNamed: "Bottom")
let bottom2 = SKSpriteNode(imageNamed: "Bottom")
let player = SKSpriteNode(imageNamed: "Player")
var velocity = CGFloat(0)
var onGround = true
var value = CGFloat(5)
override func didMove(to view: SKView) {
// Hintergrund
self.backgroundColor = SKColor.lightGray
bottom1.anchorPoint = CGPoint.zero
bottom1.position = CGPoint.zero
bottom1.zPosition = 1
self.addChild(bottom1)
bottom2.anchorPoint = CGPoint.zero
bottom2.position = CGPoint(x: bottom1.size.width - 1, y: 0)
bottom2.zPosition = 1
self.addChild(bottom2)
// Spieler
player.position = CGPoint(x: player.size.width / 2 + 20, y: bottom1.size.height + player.size.height / 2)
player.zPosition = 2
self.addChild(player)
//Balken
addBalken(xScale: 1.5, yScale: 1, name: "ba1", xPoint: 0)
}
func addBalken(xScale: CGFloat, yScale: CGFloat, name: String, xPoint: CGFloat) {
let balken = SKSpriteNode(imageNamed: "Balken")
balken.anchorPoint = CGPoint.zero
balken.position = CGPoint(x: self.size.width + (2 * balken.size.width) + xPoint, y: bottom1.size.height - 16)
balken.zPosition = 1
balken.xScale = xScale
balken.yScale = yScale
balken.name = name
addChild(balken)
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
if onGround == true {
velocity = -16
onGround = false
self.run(SKAction.playSoundFileNamed("Jump.wav", waitForCompletion: false))
}
}
override func update(_ currentTime: TimeInterval) {
//Player
player.zRotation -= CGFloat(Double.pi * 5) / 180
velocity += 0.6
player.position.y -= velocity
if player.position.y <= bottom1.size.height {
player.position.y = bottom1.size.height
velocity = 0
onGround = true
}
//Bottom
bottom1.position.x -= 4
bottom2.position.x -= 4
if bottom1.position.x < -bottom1.size.width {
bottom1.position.x = bottom2.position.x + bottom2.size.width
} else if bottom2.position.x < -bottom2.size.width {
bottom2.position.x = bottom1.position.x + bottom1.size.width
}
//Balken - ** THIS IS THE PART WHERE THE ERROR OCCURS **
let balke1 = self.childNode(withName: "//ba1") as! SKSpriteNode
balke1.position.x -= value
if balke1.position.x < self.size.width {
balke1.position.x = self.size.width + (2 * balke1.size.width)
value = CGFloat(arc4random_uniform(UInt32(value)))
}
}
}我只想调用节点，这样我就可以使用它来实现游戏中的条。
回答 1
Stack Overflow用户
发布于 2019-06-10 00:34:31
更改以下代码行：
addBalken(xScale: 1.5, yScale: 1, name: "//ba1", xPoint: 0)至：
addBalken(xScale: 1.5, yScale: 1, name: "ba1", xPoint: 0)//仅在搜索节点时适用，因此请在该行中保留以下字符：
let balke1 = self.childNode(withName: "//ba1") as! SKSpriteNode编辑：
我认为问题的根本原因是您忘记在addBalken函数中调用addChild。仅仅创建一个节点是不够的。节点也必须添加到场景中。所以这是最终的代码：
func addBalken(xScale: CGFloat, yScale: CGFloat, name: String, xPoint: CGFloat) {
let balken = SKSpriteNode(imageNamed: "Balken")
balken.anchorPoint = CGPoint.zero
balken.position = CGPoint(x: self.size.width + (2 * balken.size.width) + xPoint, y: bottom1.size.height - 16)
balken.zPosition = 1
balken.xScale = xScale
balken.yScale = yScale
balken.name = name
//add the node to the scene
addChild(balken)
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/56515428
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