swift - 如何从 GameViewController 更新 SKScene 中的变量？

Question

我已将 admob 奖励视频添加到我的应用中。 admob 一切正常。但是，我无法在观看奖励视频后更新直播标签。如果我去另一个场景然后回来，它会更新并显示新值。

//GameViewController.swift

 func rewardBasedVideoAd(_ rewardBasedVideoAd: GADRewardBasedVideoAd,
                            didRewardUserWith reward: GADAdReward) {
        print("Reward received with currency: \(reward.type), amount \(reward.amount).")


        GameData.shared.lives = GameData.shared.lives + 1
        UserDefaults.standard.set(GameData.shared.lives, forKey: "lives")
        UserDefaults.standard.synchronize()
    }

//主场景.swift

var lives = UserDefaults.standard.integer(forKey: "lives") {
        didSet{
            livesLabel?.text = "\(lives)"
        }
    }

//

Answer 1

我个人的建议是通过计算属性与场景建立联系:

class ViewController : UIViewController
{
    var mainScene : MainScene? { return (self.view as SKView?).scene as? MainScene}
    var lives : Int
    {
        get
        {
            return mainScene?.lives ?? 0
        }
        set
        {
           mainScene?.lives = newValue
           //perhaps do some error handling if mainscne is nil
        }
   }
}

然后在你的主场景中，你控制 lives 如何写入 userdefaults

class MainScene : SKScene
{
    private var _lives : Int?
    var lives : Int
    {
        get
        {
            _lives = _lives ?? UserDefaults.standard.integer(forKey: "lives")
            return _lives!
        }
        set
        {
            _lives = newValue
            UserDefaults.standard.set(_lives, forKey: "lives")
            UserDefaults.standard.synchronize()
            livesLabel?.text = "\(_lives)"
        }
    }
}

最后要使用它，你会做:

 func rewardBasedVideoAd(_ rewardBasedVideoAd: GADRewardBasedVideoAd,
                        didRewardUserWith reward: GADAdReward) {
    print("Reward received with currency: \(reward.type), amount \(reward.amount).")

    lives += 1
}

这样我们就可以避免处理全局变量，这意味着出现错误和错误的机会更少