如何解决 Swift Playgrounds 中的“运行 此页面出现问题”消息？
How do I address the “There was a problem running this page” message in Swift Playgrounds?
我正在尝试使用 SceneKit 为 WWDC 学生挑战赛制作一些东西，这要求我的项目在 Swift 操场上。我不断收到这样的消息：“此页面 运行 有问题。”它不提供错误消息。它只是建议检查我的代码或重新开始。我曾尝试单独删除代码片段，但我无法找到此问题的根源。我还在 man Xcode playground 中尝试了 运行 它，它提供了警告，我引用，“the playground could not continue 运行 because the playground source did”。我卡住了。我的代码有什么问题。
import UIKit
import SceneKit
import QuartzCore
import PlaygroundSupport
class GameScene: UIViewController, SCNSceneRendererDelegate {
var primaryView: SCNView!
var primaryScene: SCNScene!
var cameraNode: SCNNode!
override func viewDidLoad() {
sceneAndViewInit()
cameraInit()
createGround()
moonInit()
}
func createGround() {
var ground = SCNBox(width: 200, height: 1, length: 200, chamferRadius: 0)
var groundPhysicsShape = SCNPhysicsShape(geometry: ground, options: nil)
var groundNode = SCNNode(geometry: ground)
ground.firstMaterial?.diffuse.contents = UIColor.orange
ground.firstMaterial?.specular.contents = UIColor.white
groundNode.position = SCNVector3(0, -6, 0)
groundNode.physicsBody = SCNPhysicsBody(type: .static, shape: groundPhysicsShape)
primaryScene.rootNode.addChildNode(groundNode)
}
func sceneAndViewInit() {
primaryView = SCNView(frame: CGRect(x: 0, y: 0, width: 500, height: 300))
primaryView.allowsCameraControl = true
primaryView.autoenablesDefaultLighting = true
primaryScene = SCNScene()
primaryView.scene = primaryScene
primaryView.isPlaying = true
}
func cameraInit() {
var cameraNode = SCNNode()
cameraNode.camera = SCNCamera()
cameraNode.position = SCNVector3(x: 0, y: 0, z: 2)
cameraNode.camera?.fieldOfView = 65
cameraNode.camera?.wantsHDR = false
primaryScene.rootNode.addChildNode(cameraNode)
}
func moonInit() {
let moonScene = SCNScene(named: "Moon.scn")
var moonNode = moonScene?.rootNode.childNode(withName: "Sphere", recursively: true)
var moonPhysicsShape = SCNPhysicsShape(node: moonNode!, options: nil)
moonNode?.position = SCNVector3(0, 0, 0)
moonNode?.scale = SCNVector3(1, 1, 1)
moonNode?.name = "Moon"
moonNode?.physicsBody = SCNPhysicsBody(type: .static, shape: moonPhysicsShape)
primaryScene.rootNode.addChildNode(moonNode!)
}
func renderer(_ aRenderer: SCNSceneRenderer, updateAtTime time: TimeInterval) {
print(time)
}
}
let gameScene = GameScene()
PlaygroundPage.current.liveView = gameScene
（“Moon.scn”是我在 resources/files 部分中的一个文件及其纹理，但没有任何与月亮相关的代码，我仍然有这个问题。）
我找到了解决这个问题的方法。但是，我只能为您提供一个关于问题是什么以及如何解决它的全面想法。
问题似乎出在 class.
顶部的变量声明
var primaryView: SCNView!
var primaryScene: SCNScene!
var cameraNode: SCNNode!
类型后面的感叹号表示变量是一个 implicitly-unwrapped optional（我引用 this Stack Overflow response 更深入地解释了这是什么），但或多或少的变量每当使用时都会自动强制解包。我对 Swift 的工作知识多于技术知识，所以我的猜测是，当创建 GameScene 对象时，合成初始化程序会尝试设置这些变量，出于某种原因，它，需要读取变量，获取 nil，无法继续。
解决方案似乎是将变量的值放在它们的初始声明中（可能有更好的解决方案，但这至少在我的测试中有效。），因此它们不是 nil初始化程序。现在我不能在这里完全解释这个问题的原因是这似乎只对 SCNScene 变量是必要的。我真的不知道为什么会这样。
代码（***标记重要评论）：
import UIKit
import SceneKit
import QuartzCore
import PlaygroundSupport
class GameScene: UIViewController, SCNSceneRendererDelegate {
var primaryView: SCNView!// = SCNView(frame: CGRect(x: 0, y: 0, width: 500, height: 300)) //***This seems to work for reasons beyond me with the implicitly-unwrapped optional***
var primaryScene = SCNScene() //***The implicitly unwrapped optional is removed here***
var cameraNode = SCNNode() //***The implicitly unwrapped optional is removed here (I am not sure if that is necessary but it probably good practice not to use it anywhere intros code. I use it earlier to demonstrate its weird complexities.)***
override func viewDidLoad() {
sceneAndViewInit()
cameraInit()
createGround()
//moonInit() ***I removed this for simplicity in the answer***
}
func createGround() {
var ground = SCNBox(width: 200, height: 1, length: 200, chamferRadius: 0)
var groundPhysicsShape = SCNPhysicsShape(geometry: ground, options: nil)
var groundNode = SCNNode(geometry: ground)
ground.firstMaterial?.diffuse.contents = UIColor.orange
ground.firstMaterial?.specular.contents = UIColor.white
groundNode.position = SCNVector3(0, -6, 0)
groundNode.physicsBody = SCNPhysicsBody(type: .static, shape: groundPhysicsShape)
primaryScene.rootNode.addChildNode(groundNode)
}
func sceneAndViewInit() {
primaryView = SCNView(frame: CGRect(x: 0, y: 0, width: 500, height: 300))
primaryView.allowsCameraControl = true
primaryView.autoenablesDefaultLighting = true
//primaryScene = SCNScene() ***This is not necessary when it is declared above***
self.primaryView.scene = primaryScene
//primaryView.isPlaying = true
self.view = primaryView //***I realized later you need this bit of code or the program will only display a blank screen***
}
func cameraInit() {
//var cameraNode = SCNNode()
cameraNode.camera = SCNCamera()
cameraNode.position = SCNVector3(x: 0, y: 0, z: 2)
cameraNode.camera?.fieldOfView = 65
cameraNode.camera?.wantsHDR = false
primaryScene.rootNode.addChildNode(cameraNode)
}
func moonInit() {
let moonScene = SCNScene(named: "Moon.scn")
var moonNode = moonScene?.rootNode.childNode(withName: "Sphere", recursively: true)
var moonPhysicsShape = SCNPhysicsShape(node: moonNode!, options: nil)
moonNode?.position = SCNVector3(0, 0, 0)
moonNode?.scale = SCNVector3(1, 1, 1)
moonNode?.name = "Moon"
moonNode?.physicsBody = SCNPhysicsBody(type: .static, shape: moonPhysicsShape)
primaryScene.rootNode.addChildNode(moonNode!)
}
func renderer(_ aRenderer: SCNSceneRenderer, updateAtTime time: TimeInterval) {
print(time)
}
}
let gameScene = GameScene()
PlaygroundPage.current.liveView = gameScene
最后一点：
self.view = primaryView 代码非常重要。我在完整代码中做了注释，但我发现这种方式很难在互联网上找到。我认为这与 UIViewController 有关（我对 UIKit 了解不多。），但是如果您 SceneKit 或 UIKit 只是显示一个空白屏幕现在确实有那么一点代码。如果你不知道这些是不同的问题，它们真的很难破译。
要查看完整的错误消息，请转到“设置”应用 -> Playgrounds -> 打开“创作调试模式”。这并不能直接解决问题，但对定位错误更有帮助。
我正在尝试使用 SceneKit 为 WWDC 学生挑战赛制作一些东西，这要求我的项目在 Swift 操场上。我不断收到这样的消息：“此页面 运行 有问题。”它不提供错误消息。它只是建议检查我的代码或重新开始。我曾尝试单独删除代码片段，但我无法找到此问题的根源。我还在 man Xcode playground 中尝试了 运行 它，它提供了警告，我引用，“the playground could not continue 运行 because the playground source did”。我卡住了。我的代码有什么问题。
import UIKit
import SceneKit
import QuartzCore
import PlaygroundSupport
class GameScene: UIViewController, SCNSceneRendererDelegate {
var primaryView: SCNView!
var primaryScene: SCNScene!
var cameraNode: SCNNode!
override func viewDidLoad() {
sceneAndViewInit()
cameraInit()
createGround()
moonInit()
}
func createGround() {
var ground = SCNBox(width: 200, height: 1, length: 200, chamferRadius: 0)
var groundPhysicsShape = SCNPhysicsShape(geometry: ground, options: nil)
var groundNode = SCNNode(geometry: ground)
ground.firstMaterial?.diffuse.contents = UIColor.orange
ground.firstMaterial?.specular.contents = UIColor.white
groundNode.position = SCNVector3(0, -6, 0)
groundNode.physicsBody = SCNPhysicsBody(type: .static, shape: groundPhysicsShape)
primaryScene.rootNode.addChildNode(groundNode)
}
func sceneAndViewInit() {
primaryView = SCNView(frame: CGRect(x: 0, y: 0, width: 500, height: 300))
primaryView.allowsCameraControl = true
primaryView.autoenablesDefaultLighting = true
primaryScene = SCNScene()
primaryView.scene = primaryScene
primaryView.isPlaying = true
}
func cameraInit() {
var cameraNode = SCNNode()
cameraNode.camera = SCNCamera()
cameraNode.position = SCNVector3(x: 0, y: 0, z: 2)
cameraNode.camera?.fieldOfView = 65
cameraNode.camera?.wantsHDR = false
primaryScene.rootNode.addChildNode(cameraNode)
}
func moonInit() {
let moonScene = SCNScene(named: "Moon.scn")
var moonNode = moonScene?.rootNode.childNode(withName: "Sphere", recursively: true)
var moonPhysicsShape = SCNPhysicsShape(node: moonNode!, options: nil)
moonNode?.position = SCNVector3(0, 0, 0)
moonNode?.scale = SCNVector3(1, 1, 1)
moonNode?.name = "Moon"
moonNode?.physicsBody = SCNPhysicsBody(type: .static, shape: moonPhysicsShape)
primaryScene.rootNode.addChildNode(moonNode!)
}
func renderer(_ aRenderer: SCNSceneRenderer, updateAtTime time: TimeInterval) {
print(time)
}
}
let gameScene = GameScene()
PlaygroundPage.current.liveView = gameScene
（“Moon.scn”是我在 resources/files 部分中的一个文件及其纹理，但没有任何与月亮相关的代码，我仍然有这个问题。）
我找到了解决这个问题的方法。但是，我只能为您提供一个关于问题是什么以及如何解决它的全面想法。
问题似乎出在 class.
var primaryView: SCNView!
var primaryScene: SCNScene!
var cameraNode: SCNNode!
类型后面的感叹号表示变量是一个 implicitly-unwrapped optional（我引用 this Stack Overflow response 更深入地解释了这是什么），但或多或少的变量每当使用时都会自动强制解包。我对 Swift 的工作知识多于技术知识，所以我的猜测是，当创建 GameScene 对象时，合成初始化程序会尝试设置这些变量，出于某种原因，它，需要读取变量，获取 nil，无法继续。
解决方案似乎是将变量的值放在它们的初始声明中（可能有更好的解决方案，但这至少在我的测试中有效。），因此它们不是 nil初始化程序。现在我不能在这里完全解释这个问题的原因是这似乎只对 SCNScene 变量是必要的。我真的不知道为什么会这样。
代码（***标记重要评论）：
import UIKit
import SceneKit
import QuartzCore
import PlaygroundSupport
class GameScene: UIViewController, SCNSceneRendererDelegate {
var primaryView: SCNView!// = SCNView(frame: CGRect(x: 0, y: 0, width: 500, height: 300)) //***This seems to work for reasons beyond me with the implicitly-unwrapped optional***
var primaryScene = SCNScene() //***The implicitly unwrapped optional is removed here***
var cameraNode = SCNNode() //***The implicitly unwrapped optional is removed here (I am not sure if that is necessary but it probably good practice not to use it anywhere intros code. I use it earlier to demonstrate its weird complexities.)***
override func viewDidLoad() {
sceneAndViewInit()
cameraInit()
createGround()
//moonInit() ***I removed this for simplicity in the answer***
}
func createGround() {
var ground = SCNBox(width: 200, height: 1, length: 200, chamferRadius: 0)
var groundPhysicsShape = SCNPhysicsShape(geometry: ground, options: nil)
var groundNode = SCNNode(geometry: ground)
ground.firstMaterial?.diffuse.contents = UIColor.orange
ground.firstMaterial?.specular.contents = UIColor.white
groundNode.position = SCNVector3(0, -6, 0)
groundNode.physicsBody = SCNPhysicsBody(type: .static, shape: groundPhysicsShape)
primaryScene.rootNode.addChildNode(groundNode)
}
func sceneAndViewInit() {
primaryView = SCNView(frame: CGRect(x: 0, y: 0, width: 500, height: 300))
primaryView.allowsCameraControl = true
primaryView.autoenablesDefaultLighting = true
//primaryScene = SCNScene() ***This is not necessary when it is declared above***
self.primaryView.scene = primaryScene
//primaryView.isPlaying = true
self.view = primaryView //***I realized later you need this bit of code or the program will only display a blank screen***
}
func cameraInit() {
//var cameraNode = SCNNode()
cameraNode.camera = SCNCamera()
cameraNode.position = SCNVector3(x: 0, y: 0, z: 2)
cameraNode.camera?.fieldOfView = 65
cameraNode.camera?.wantsHDR = false
primaryScene.rootNode.addChildNode(cameraNode)
}
func moonInit() {
let moonScene = SCNScene(named: "Moon.scn")
var moonNode = moonScene?.rootNode.childNode(withName: "Sphere", recursively: true)
var moonPhysicsShape = SCNPhysicsShape(node: moonNode!, options: nil)
moonNode?.position = SCNVector3(0, 0, 0)
moonNode?.scale = SCNVector3(1, 1, 1)
moonNode?.name = "Moon"
moonNode?.physicsBody = SCNPhysicsBody(type: .static, shape: moonPhysicsShape)
primaryScene.rootNode.addChildNode(moonNode!)
}
func renderer(_ aRenderer: SCNSceneRenderer, updateAtTime time: TimeInterval) {
print(time)
}
}
let gameScene = GameScene()
PlaygroundPage.current.liveView = gameScene
最后一点：
self.view = primaryView 代码非常重要。我在完整代码中做了注释，但我发现这种方式很难在互联网上找到。我认为这与 UIViewController 有关（我对 UIKit 了解不多。），但是如果您 SceneKit 或 UIKit 只是显示一个空白屏幕现在确实有那么一点代码。如果你不知道这些是不同的问题，它们真的很难破译。
要查看完整的错误消息，请转到“设置”应用 -> Playgrounds -> 打开“创作调试模式”。这并不能直接解决问题，但对定位错误更有帮助。