Unity 游戏中的存档游戏

本主题介绍如何在 Unity 游戏中使用 Play 游戏服务的存档游戏。

开始之前

显示存档游戏 UI

选择或创建存档游戏条目的标准 UI 通过调用以下方法显示

    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
        }
    }

打开存档游戏

为了读取或写入存档游戏的数据，需要打开存档游戏。由于存档游戏状态缓存在设备本地并保存到云端，因此可能会遇到保存数据状态冲突的情况。当设备尝试将状态保存到云端，但云端当前数据由另一台设备写入时，就会发生冲突。打开存档游戏数据时，需要解决这些冲突。

有两种处理冲突解决的打开方法，第一种**OpenWithAutomaticConflictResolution**接受标准的冲突解决策略类型并自动解决冲突。另一种方法**OpenWithManualConflictResolution**接受回调方法，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
        }
    }

写入存档游戏

打开存档游戏文件后，可以写入它以保存游戏状态。这是通过调用**CommitUpdate**完成的。CommitUpdate 有四个参数

  1. 传递给传递给其中一个 Open 调用的回调的存档游戏元数据。
  2. 对元数据进行的更新。
  3. 实际的字节数组数据
  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;
    }

读取存档游戏

打开存档游戏文件后，可以读取它以加载游戏状态。这是通过调用**ReadBinaryData**完成的。

    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
        }
    }

删除存档游戏

打开存档游戏文件后，可以将其删除。这是通过调用**Delete**完成的。

    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
        }
    }