Swift：如何从GameScene向ViewController传递高分变量？高分显示为0怎么办

解决GameCenter高分显示为0的问题 #

Hey there, let's work through why you're only seeing 0 when trying to send your GameScene's highscore to Game Center. Here are the key fixes to try out:

• 确认GameScene引用是否正确
  A common issue is that self.gameScene might not be pointing to the active, running instance of your GameScene. If you're using a Storyboard to set up your SKView, make sure you properly capture the scene reference in your GameViewController:

  override func viewDidLoad() {
      super.viewDidLoad()
      // 确保view是SKView，并且场景已经加载为GameScene
      guard let skView = self.view as? SKView,
            let loadedGameScene = skView.scene as? GameScene else {
          print("Failed to get reference to GameScene")
          return
      }
      self.gameScene = loadedGameScene
  }
  

  If your GameScene loads later (like after the user starts a game), self.gameScene might still be an uninitialized instance when you tap the GameCenter button—leading to that default 0 value.

• 验证GameScene中highscore是否被正确更新
  仔细检查GameScene里的highscore变量在游戏过程中是否被正确赋值，别忘了持久化存储它，避免场景重载后数据丢失：

  // 在GameScene的得分更新逻辑中
  func updateScore(newScore: Int) {
      if newScore > highscore {
          highscore = newScore
          // 保存到UserDefaults，方便后续可靠读取
          UserDefaults.standard.set(highscore, forKey: "PlayerHighScore")
      }
  }
  

  如果highscore只在游戏结束时计算，要确保这个计算在你点击GameCenter按钮前已经完成。

• 通过UserDefaults读取高分（比场景引用更可靠）
  依赖场景引用可能会因为场景销毁或重初始化失效，不如在GameViewController的按钮点击事件里直接从UserDefaults获取保存的高分：

  @IBAction func gameCenterButtonTapped(_ sender: UIButton) {
      let savedHighScore = UserDefaults.standard.integer(forKey: "PlayerHighScore")
      // 如果没有保存过的高分，再回退到场景中的highscore
      let scoreToSubmit = savedHighScore != 0 ? savedHighScore : (self.gameScene?.highscore ?? 0)
      saveHighScore(number: scoreToSubmit)
  }
  

  这样即使GameScene的引用出问题，你也能拿到最后保存的真实高分。

• 检查saveHighScore函数的实现
  确保你的saveHighScore函数正确处理了GameCenter认证和分数提交流程。如果用户未登录，分数根本无法提交，排行榜自然会显示0：

  func saveHighScore(number: Int) {
      guard GKLocalPlayer.local.isAuthenticated else {
          // 提示用户登录GameCenter
          GKLocalPlayer.local.authenticateHandler = { [weak self] viewController, error in
              guard let self = self else { return }
              if let loginVC = viewController {
                  self.present(loginVC, animated: true)
              } else if GKLocalPlayer.local.isAuthenticated {
                  // 登录成功后重新提交分数
                  self.saveHighScore(number: number)
              }
          }
          return
      }
      
      let score = GKScore(leaderboardIdentifier: "YOUR_LEADERBOARD_ID")
      score.value = Int64(number)
      
      GKScore.report([score]) { error in
          if let error = error {
              print("Failed to submit score: \(error.localizedDescription)")
          } else {
              print("Highscore submitted successfully!")
          }
      }
  }
  

  还要确认代码里的排行榜ID和你在苹果开发者后台配置的完全一致——拼写错误是常见的问题根源。

• 验证GameCenter排行榜的配置
  确保你在苹果开发者控制台正确创建了排行榜，ID匹配无误，并且应用的Bundle ID和注册信息一致。如果排行榜关联不正确，分数提交会失败，排行榜就会显示默认的0分。

内容的提问来源于stack exchange，提问作者Tom Sanchez