Swift，SpriteKit：释放游戏场景并重新分配新场景

Question

我需要在玩家完成一个关卡后释放游戏场景，以便内存可用于加载我的游戏的另一个关卡。如果我不这样做，我的应用程序会因为内存问题而崩溃。

我已按照那里给出的指示：

Swift: Deallocate GameScene after transition to new scene?

但不幸的是，它对我不起作用。我在我的 GameViewController 类中收到错误“无法将值 'UIView' 转换为 'SKView'。这是我的整个代码：

import Foundation
import UIKit
import SpriteKit

class GameViewController: UIViewController {

    var scene1: SKScene?
    var scene2: SKScene?
    var scene3: SKScene?
    var skView: SKView?


    func nextSceneAction1() {

        scene2 = nil
        scene3 = nil

        skView! = self.view as! SKView
        skView!.showsFPS = true
        skView!.showsNodeCount = true

        /* Sprite Kit applies additional optimizations to improve rendering performance */
        skView!.ignoresSiblingOrder = true

        scene1 = TransitionSigns(size: skView!.frame.size)
        scene1!.size.width = 2048
        scene1!.size.height = 1536


        /* Set the scale mode to scale to fit the window */
        scene1!.scaleMode = .AspectFill

        let transition = SKTransition.revealWithDirection(.Right, duration: 2)

        scene1!.scaleMode = .AspectFill
        skView!.presentScene(scene1!, transition: transition)
    }

    func nextSceneAction2() {

        scene1 = nil
        scene3 = nil

        let skView = self.view as! SKView
        skView.showsFPS = true
        skView.showsNodeCount = true

        /* Sprite Kit applies additional optimizations to improve rendering performance */
        skView.ignoresSiblingOrder = true

        scene2 = TransitionSigns(size: skView.frame.size)
        scene2!.size.width = 2048
        scene2!.size.height = 1536


        /* Set the scale mode to scale to fit the window */
        scene2!.scaleMode = .AspectFill

        let transition = SKTransition.revealWithDirection(.Right, duration: 2)

        scene2!.scaleMode = .AspectFill
        skView.presentScene(scene2!, transition: transition)
    }

    func nextSceneAction3() {

        scene1 = nil
        scene2 = nil

        let skView = self.view as! SKView
        skView.showsFPS = true
        skView.showsNodeCount = true

        /* Sprite Kit applies additional optimizations to improve rendering performance */
        skView.ignoresSiblingOrder = true

        scene3 = TransitionSigns(size: skView.frame.size)
        scene3!.size.width = 2048
        scene3!.size.height = 1536


        /* Set the scale mode to scale to fit the window */
        scene3!.scaleMode = .AspectFill

        let transition = SKTransition.revealWithDirection(.Right, duration: 2)

        scene3!.scaleMode = .AspectFill
        skView.presentScene(scene3!, transition: transition)
    }


    override func viewWillLayoutSubviews() {
        // Configure the view.

        let skView = self.view as! SKView
        skView.showsFPS = true
        skView.showsNodeCount = true

        /* Sprite Kit applies additional optimizations to improve rendering performance */
        skView.ignoresSiblingOrder = true

        let scene = MainView(size: skView.frame.size)
        scene.size.width = 2048
        scene.size.height = 1536

        /* Set the scale mode to scale to fit the window */
        scene.scaleMode = .AspectFill

        skView.presentScene(scene)
    }

    override func shouldAutorotate() -> Bool {
        return true
    }

    override func supportedInterfaceOrientations() ->   UIInterfaceOrientationMask {
        if UIDevice.currentDevice().userInterfaceIdiom == .Phone {
            return UIInterfaceOrientationMask.AllButUpsideDown
        } else {
            return UIInterfaceOrientationMask.All
        }
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Release any cached data, images, etc that aren't in use.
    }

    override func prefersStatusBarHidden() -> Bool {
        return true
    }


    override func viewDidLoad() {
        super.viewDidLoad()

    }

    override func viewDidDisappear(animated: Bool) {

        self.view.removeFromSuperview()
    }

    override func viewWillDisappear(animated: Bool){
        self.view.removeFromSuperview()
    }
}

我从我的其他类中调用不同的函数nextSceneAction1()、nextSceneAction2() 和nextSceneAction3()：

let controller1 = GameViewController()
controller1.nextSceneAction1()

或

let controller2 = GameViewController()
controller2.nextSceneAction1()

加载新场景时，我收到此错误：“无法将 'UIView' 类型的值转换为 'SKView'。你知道这段代码有什么问题吗？

顺便说一句，我愿意在加载新场景之前从内存中清除旧场景，以便在应用程序的生命周期内不会发生内存崩溃。

Answer 1

一般来说，一旦您转换到新场景，SKScene 会自动解除分配，除非您有内存泄漏，因此通常您不需要做任何特别的事情来释放内存。

要查看您的场景是否已解除分配，您可以添加 deinit 方法

  func deinit {
      print("scene did deallocate")
  }

如果这个方法在你改变场景时被调用，你就知道所有的东西都被正确释放了，如果它没有被调用，你就有内存泄漏。

您的代码也有问题，每次更改场景而不是访问当前实例时，您都会创建一个新的 GameViewController 实例。

 let controller2 = GameViewController() // creates new instance of GameViewController
 controller2.nextSceneAction1()

您通常只从 GameViewController 加载第一个场景，而所有其他场景更改都可以直接在您所在的 SKScene 中完成。不要为此使用 GameViewController。

在您当前的 SKScene 中，您可以像这样更改为新场景（例如从 GameScene 到 MenuScene）

 class GameScene: SKScene {

      ...


       func loadMenuScene() {

           let menuScene = MenuScene(size: self.size) // use size of current scene          
           let transition = Some SKTransition
           view?.presentScene(menuScene, withTransition: transition)
      }  
 }

希望对你有帮助