Unity 游戏中的游戏存档

本主题介绍了如何在 Unity 游戏中使用 Play 游戏服务的游戏存档。

开始之前

  • 设置您的项目和适用于 Unity 的 Google Play 游戏插件。有关详细信息，请参阅入门指南。

  • 启用游戏存档。有关详细信息，请参阅游戏存档。

显示游戏存档 UI

通过调用以下方法可显示用于选择或创建游戏存档条目的标准 UI：

    void ShowSelectUI() {
        uint maxNumToDisplay = 5;
        bool allowCreateNew = false;
        bool allowDelete = true;

        ISavedGameClient savedGameClient = PlayGamesPlatform.Instance.SavedGame;
        savedGameClient.ShowSelectSavedGameUI("Select saved game",
            maxNumToDisplay,
            allowCreateNew,
            allowDelete,
            OnSavedGameSelected);
    }

    public void OnSavedGameSelected (SelectUIStatus status, ISavedGameMetadata game) {
        if (status == SelectUIStatus.SavedGameSelected) {
            // handle selected game save
        } else {
            // handle cancel or error
        }
    }

打开游戏存档

为了读取或写入游戏存档数据，需要先打开游戏存档。由于游戏存档状态在设备本地缓存并保存到云端，因此可能会遇到存档数据状态冲突的情况。当设备尝试将状态保存到云端，但云端当前数据是由不同设备写入时，就会发生冲突。在打开游戏存档数据时，需要解决这些冲突。

有两种打开方法用于处理冲突解决，第一种是 OpenWithAutomaticConflictResolution，它接受一种标准解决策略类型并自动解决冲突。另一种方法 OpenWithManualConflictResolution 接受一个回调方法，以允许手动解决冲突。

有关这些方法的更多详细信息，请参阅 GooglePlayGames/BasicApi/SavedGame/ISavedGameClient.cs。

    void OpenSavedGame(string filename) {
        ISavedGameClient savedGameClient = PlayGamesPlatform.Instance.SavedGame;
        savedGameClient.OpenWithAutomaticConflictResolution(filename, DataSource.ReadCacheOrNetwork,
            ConflictResolutionStrategy.UseLongestPlaytime, OnSavedGameOpened);
    }

    public void OnSavedGameOpened(SavedGameRequestStatus status, ISavedGameMetadata game) {
        if (status == SavedGameRequestStatus.Success) {
            // handle reading or writing of saved game.
        } else {
            // handle error
        }
    }

写入游戏存档

游戏存档文件打开后，可以写入数据以保存游戏状态。这通过调用 CommitUpdate 完成。CommitUpdate 有四个参数：

  1. 传递给某个 Open 调用所传递回调的游戏存档元数据。
  2. 对元数据进行的更新。
  3. 实际的数据字节数组
  4. 提交完成后要调用的回调。
    void SaveGame (ISavedGameMetadata game, byte[] savedData, TimeSpan totalPlaytime) {
        ISavedGameClient savedGameClient = PlayGamesPlatform.Instance.SavedGame;

        SavedGameMetadataUpdate.Builder builder = new SavedGameMetadataUpdate.Builder();
        builder = builder
            .WithUpdatedPlayedTime(totalPlaytime)
            .WithUpdatedDescription("Saved game at " + DateTime.Now());
        if (savedImage != null) {
            // This assumes that savedImage is an instance of Texture2D
            // and that you have already called a function equivalent to
            // getScreenshot() to set savedImage
            // NOTE: see sample definition of getScreenshot() method below
            byte[] pngData = savedImage.EncodeToPNG();
            builder = builder.WithUpdatedPngCoverImage(pngData);
        }
        SavedGameMetadataUpdate updatedMetadata = builder.Build();
        savedGameClient.CommitUpdate(game, updatedMetadata, savedData, OnSavedGameWritten);
    }

    public void OnSavedGameWritten (SavedGameRequestStatus status, ISavedGameMetadata game) {
        if (status == SavedGameRequestStatus.Success) {
            // handle reading or writing of saved game.
        } else {
            // handle error
        }
    }

    public Texture2D getScreenshot() {
        // Create a 2D texture that is 1024x700 pixels from which the PNG will be
        // extracted
        Texture2D screenShot = new Texture2D(1024, 700);

        // Takes the screenshot from top left hand corner of screen and maps to top
        // left hand corner of screenShot texture
        screenShot.ReadPixels(
            new Rect(0, 0, Screen.width, (Screen.width/1024)*700), 0, 0);
        return screenShot;
    }

读取游戏存档

游戏存档文件打开后，可以读取数据以加载游戏状态。这通过调用 ReadBinaryData 完成。

    void LoadGameData (ISavedGameMetadata game) {
        ISavedGameClient savedGameClient = PlayGamesPlatform.Instance.SavedGame;
        savedGameClient.ReadBinaryData(game, OnSavedGameDataRead);
    }

    public void OnSavedGameDataRead (SavedGameRequestStatus status, byte[] data) {
        if (status == SavedGameRequestStatus.Success) {
            // handle processing the byte array data
        } else {
            // handle error
        }
    }

删除游戏存档

游戏存档文件打开后，可以删除。这通过调用 Delete 完成。

    void DeleteGameData (string filename) {
        // Open the file to get the metadata.
        ISavedGameClient savedGameClient = PlayGamesPlatform.Instance.SavedGame;
        savedGameClient.OpenWithAutomaticConflictResolution(filename, DataSource.ReadCacheOrNetwork,
            ConflictResolutionStrategy.UseLongestPlaytime, DeleteSavedGame);
    }

    public void DeleteSavedGame(SavedGameRequestStatus status, ISavedGameMetadata game) {
        if (status == SavedGameRequestStatus.Success) {
            ISavedGameClient savedGameClient = PlayGamesPlatform.Instance.SavedGame;
            savedGameClient.Delete(game);
        } else {
            // handle error
        }
    }