“SystemInfo.deviceUniqueIdentifier”在 Android 构建中使用什么？

The 文档 https://docs.unity3d.com/ScriptReference/SystemInfo-deviceUniqueIdentifier.html记录 iOS/Windows 版本中使用的标识符，但 Android 版本中不使用该标识符。标识符有什么作用SystemInfo.deviceUniqueIdentifier在安卓上使用？

我不明白为什么文档中没有提到这一点。

上次我检查时，Unity 使用Secure.ANDROID_ID https://stackoverflow.com/a/2785493/3785314获取 Android ID 字符串，然后将其转换为字符串。如果你这样做，你的值应该与SystemInfo.deviceUniqueIdentifier https://docs.unity3d.com/ScriptReference/SystemInfo-deviceUniqueIdentifier.html。这就是我的设备上发生的情况。

不幸的是，更多的事情正在幕后发生。

Unity 在其网站上记录了其唯一标识符详细信息实现forum https://forum.unity3d.com/threads/unique-identifier-details.353256/.

1。获取设备IDcontext.getSystemService(Context.TElEPHONY_SERVICE).getDeviceId()

2.If #1失败，获取 Android IDcontext.getContentResolver().getString(Secure.ANDROID_ID);

3.If #2失败，获取Mac地址。

4.转换结果来自#1, #2 or #3（无论哪一个成功）转换为 MD5 哈希值。

值得一读forum https://forum.unity3d.com/threads/unique-identifier-details.353256/由于某些 Unity 版本的行为略有不同，因此请发布此帖子。

这是他们提供的示例代码：

// Hash an input string and return the hash as
// a 32 character hexadecimal string.
static string getMd5Hash(string input)
{
    if (input == "")
        return "";
    MD5CryptoServiceProvider md5Hasher = new MD5CryptoServiceProvider();
    byte[] data = md5Hasher.ComputeHash(Encoding.Default.GetBytes(input));
    StringBuilder sBuilder = new StringBuilder();
    for (int i = 0; i < data.Length; i++)
        sBuilder.Append(data[i].ToString("x2"));
    return sBuilder.ToString();
}

static string generateDeviceUniqueIdentifier(bool oldBehavior)
{
    string id = "";
    AndroidJavaClass jc = new AndroidJavaClass("com.unity3d.player.UnityPlayer");
    AndroidJavaObject activity = jc.GetStatic<AndroidJavaObject>("currentActivity");
    AndroidJavaClass contextClass = new AndroidJavaClass("android.content.Context");
    string TELEPHONY_SERVICE = contextClass.GetStatic<string>("TELEPHONY_SERVICE");
    AndroidJavaObject telephonyService = activity.Call<AndroidJavaObject>("getSystemService", TELEPHONY_SERVICE);
    bool noPermission = false;
    try
    {
        id = telephonyService.Call<string>("getDeviceId");
    }
    catch (Exception e) {
        noPermission = true;
    }
    if(id == null)
        id = "";
    // <= 4.5 : If there was a permission problem, we would not read Android ID
    // >= 4.6 : If we had permission, we would not read Android ID, even if null or "" was returned
    if((noPermission && !oldBehavior) || (!noPermission && id == "" && oldBehavior))
    {
        AndroidJavaClass settingsSecure = new AndroidJavaClass("android.provider.Settings$Secure");
        string ANDROID_ID = settingsSecure.GetStatic<string>("ANDROID_ID");
        AndroidJavaObject contentResolver = activity.Call<AndroidJavaObject>("getContentResolver");
        id = settingsSecure.CallStatic<string>("getString", contentResolver, ANDROID_ID);
        if(id == null)
            id = "";
    }
    if(id == "")
    {
        string mac = "00000000000000000000000000000000";
        try
        {
            StreamReader reader = new StreamReader("/sys/class/net/wlan0/address");
            mac = reader.ReadLine();
            reader.Close();
        }
        catch (Exception e) {}
        id = mac.Replace(":", "");
    }
    return getMd5Hash(id);
}