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Unity persistentDataPath使用案例
一、Application.persistentDataPath
1、概念
persistentDataPath：此属性用于返回一个持久化数据存储目录的路径，可以在此路径下存储一些持久化的数据文件；是一个可读写的目录；此文件夹在Editor阶段没有，手机安装App后自动生成；
关联的概念-Unity项目文件夹StreamingAssets：只能读,不能写。
2、应用场景
1）手机应用场景中存储当前游戏的进度，以便下次运行游戏时读取
如下代码文件，存储游戏中的下列数据coins、starCount = 0、collection
[Serializable]
public class SaveData
{
//Current loaded save file
public static SaveData save;
private static string fileName;
//Unsaved global variables
public static bool checkpoint = false;
public static Vector3 checkpointPos;
public static Quaternion checkpointRot;
public static bool hubPositionSet = false;
//Saved variables
public int coins = 0;
public int starCount = 0;
public List<string> collection = new List<string>();
//Save
public void Save()
{
System.IO.File.WriteAllText(fileName, JsonUtility.ToJson(this));
}
//Load (Make sure fileName is set, will be loaded if it exists)
public static bool Load()
{
if (System.IO.File.Exists(fileName))
{
save = JsonUtility.FromJson<SaveData>(System.IO.File.ReadAllText(fileName));
hubPositionSet = true;
return true;
}
else
return false;
}
//Create new game
public static void NewGame()
{
save = new SaveData();
hubPositionSet = false;
}
public static void SetFileName(string name)
{
fileName = Path.Combine(Application.persistentDataPath, name + ".json");
}
//Null check
public static void NullCheck()
{
if (save == null)
{
SetFileName("TestSave");
if (!Load()) NewGame();
Debug.Log("Hello Mario Framework: Using test save file!");
hubPositionSet = false;
}
}
//Get coin count
public int GetCoins()
{
return coins;
}
//Add or remove coins
public void AddCoins(int i)
{
coins += i;
}
//Collect a single coin
public void CollectCoin()
{
coins++;
}
//Get star count
public int GetStarCount()
{
return starCount;
}
//Collect a star (Or ignore if already collected)
public bool CollectStar(string name)
{
if (AddCollection(name))
{
starCount++;
return true;
}
else return false;
}
//Add to collection
public bool AddCollection(string id)
{
if (!collection.Contains(id))
{
collection.Add(id);
return true;
}
else return false;
}
//Check if something is in the collection
public bool CheckCollection(string id)
{
return collection.Contains(id);
}
}
2）放置一些首次运行时需要的可读写的数据文件
将游戏运行时需要的可读写的文件模板放到只读文件夹“StreamingAssets”，手机首次运行时再拷贝到可读写的目录“Application.persistentDataPath”，
如下实例，游戏在手机平台首次运行时将我们的数据模板文件”data.txt”拷贝到“persistentDataPath”目录，以便于以后在手机端游戏运行时实时读写。
public void copy(string fileName = "data.txt")
{
string url;
//Mac，Windows或Linux平台
#if UNITY_EDITOR || UNITY_STANDALONE
url = $"file://{Application.dataPath}/StreamingAssets/{fileName}";
//ios平台路径
#elif UNITY_IPHONE
url = $"file://{Application.dataPath}/Raw/{fileName}";
//安卓路径
#elif UNITY_ANDROID
url = $"jar:file://{Application.dataPath}!/assets/{fileName}";
#endif
string persistentUrl = $"{Application.persistentDataPath}/{fileName}";
if (!File.Exists(persistentUrl))
{
Debug.Log($"{persistentUrl} 文件不存在,从StreamingAssets中Copy!");
WWW www = new WWW(url);
while (true)
{
if (www.isDone)
{
if (www.error == null)
{
//本次读的文本
File.WriteAllText(persistentUrl, www.text);
File.WriteAllBytes(path, www.bytes);
Debug.Log($"持久化目录: {persistentUrl}");
break;
}
else
{
Debug.LogWarning($"没得到StreamingAssets的文件 : {fileName}");
}
}
}
}
else
{
Debug.Log($"{persistentUrl} 文件已存在!");
}
}