unity3d 加載卡loading 分析， android 之外置sd卡 問題

現在手機很多都可以用插拔式sd卡用來擴充存儲大小，但這些外接設備也會引發一些未知的app運行問題，先看一下sd類型

可見不同sd卡對io速度也不同，所以對app的影響也又所有不同，
在此送上一份可信的數據來看下影響層面

上圖可以看出資源下載在不同的存儲位置，反應的加載資源卡住的比例
在外置sd比內置存儲要高出1倍。
對此我們做了玩家友情提示和資源搬家功能，主要是讓玩家知道資源放在內置存儲更好，廢話不多，上代碼
1：GetExternalSDCardRootPath 這個方法用來獲取外置外置sd卡的路徑，如果沒有外置sd卡就返回null，可以用這個字符串來比對你的資源下載路徑如果存在sd卡路徑字符，那麼你的資源就在外置sd卡上面了

    private static AndroidJavaObject GetReflectMethod(string className, string methodName)
    {
        AndroidJavaObject method;
        using (AndroidJavaClass Class = new AndroidJavaClass("java.lang.Class"))
        using (AndroidJavaObject classObject = Class.CallStatic<AndroidJavaObject>("forName", className))
        {
            method = classObject.Call<AndroidJavaObject>("getDeclaredMethod", methodName, null);
            method.Call("setAccessible", true);
        }
        return method;
    }
    public static string GetExternalSDCardRootPath()
    {
        AndroidJavaClass buildVersion = new AndroidJavaClass("android.os.Build$VERSION");

        if (buildVersion.GetStatic<int>("SDK_INT") >= 23)
        {
            AndroidJavaObject method_getExternalDirs = GetReflectMethod("android.os.Environment$UserEnvironment", "getExternalDirs");
            AndroidJavaObject method_myUserId = GetReflectMethod("android.os.UserHandle", "myUserId");

            AndroidJavaClass class_UserHandle = new AndroidJavaClass("android.os.UserHandle");

            AndroidJavaObject mUserId = method_myUserId.Call<AndroidJavaObject>("invoke", class_UserHandle, null);
            int userId = mUserId.Call<int>("intValue");

            AndroidJavaObject env = new AndroidJavaObject("android.os.Environment$UserEnvironment", userId);

            AndroidJavaObject rawfilesArray = method_getExternalDirs.Call<AndroidJavaObject>("invoke", env, null);

            AndroidJavaObject[] fileArray = AndroidJNIHelper.ConvertFromJNIArray<AndroidJavaObject[]>(rawfilesArray.GetRawObject());

            AndroidJavaClass Environment = new AndroidJavaClass("android.os.Environment");

            for (int i = 0; i < fileArray.Length; i++)
            {
                AndroidJavaObject file = fileArray[i];
                bool removable = Environment.CallStatic<bool>("isExternalStorageRemovable", file);
                if (removable)
                {
                    string path = file.Call<string>("getAbsolutePath");
                    return path;
                }
            }
        }
        else
        {

            using (AndroidJavaClass system = new AndroidJavaClass("java.lang.System"))
            {
                string secondaryStoragePath = system.CallStatic<string>("getenv", "SECONDARY_STORAGE");

                if (secondaryStoragePath != null)
                {
                    AndroidJavaObject file = new AndroidJavaObject("java.io.File", secondaryStoragePath);
                    bool canRead = file.Call<bool>("canRead");
                    if (canRead)
                    {
                        return secondaryStoragePath;
                    }
                }
            }
        }
        return null;
    }

2：GetInternalPersisteDataPath這個方法用來，百分百返回手機的內置存儲路徑並判定是否可讀寫。

    public static string GetInternalPersisteDataPath()
    {

        string storagePath = GetStoragePathCS(false);
        if (!string.IsNullOrEmpty(storagePath))
        {
            string forceInternalForcePath = storagePath + "/Android/Data/" + Application.identifier + "/files";
            AndroidJavaObject file = new AndroidJavaObject("java.io.File", forceInternalForcePath);
            if (!file.Call<bool>("exists"))
            {
                file.Call<bool>("mkdirs");
            }

            if (file.Call<bool>("canRead") && file.Call<bool>("canWrite"))
            {
                return file.Call<string>("getAbsolutePath");
            }
        }
        return null;
    }
    private static string GetStoragePathCS(bool is_removale)
    {
        using (AndroidJavaClass playerCls = new AndroidJavaClass("com.unity3d.player.UnityPlayer"))
        using (AndroidJavaObject activity = playerCls.GetStatic<AndroidJavaObject>("currentActivity"))
        using (AndroidJavaObject mStorageManager = activity.Call<AndroidJavaObject>("getSystemService", "storage"))
        {
            AndroidJavaObject method_getVolumeList = GetReflectMethod("android.os.storage.StorageManager", "getVolumeList");
            AndroidJavaObject method_getPath = GetReflectMethod("android.os.storage.StorageVolume", "getPath");
            AndroidJavaObject method_isRemovable = GetReflectMethod("android.os.storage.StorageVolume", "isRemovable");
            AndroidJavaObject rawVolumeList = method_getVolumeList.Call<AndroidJavaObject>("invoke", mStorageManager, null);
            AndroidJavaObject[] VolumeList = AndroidJNIHelper.ConvertFromJNIArray<AndroidJavaObject[]>(rawVolumeList.GetRawObject());

            for (int i = 0; i < VolumeList.Length; i++)
            {
                AndroidJavaObject storageVolumeElement = VolumeList[i];
                string path = method_getPath.Call<string>("invoke", storageVolumeElement, null);
                AndroidJavaObject java_removable = method_isRemovable.Call<AndroidJavaObject>("invoke", storageVolumeElement, null);
                bool removable = java_removable.Call<bool>("booleanValue");

                if (is_removale == removable)
                {
                    return path;
                }
            }
        }
        return null;
    }

3：進行資源搬家邏輯，根據上面1，2的邏輯，符合搬家標準的，我們就進行搬家
CopyDirectoryWorker類提供了資源搬家的方法和進度，參數只需要原文件路徑和新文件夾路徑即可

using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class CopyDirectoryWorker {
    public delegate void GetProgressEventHandler(int Index, int Count, string SourceFile, string AimFile);
    public event GetProgressEventHandler OnGetProgress;//定義一個事件,在Copy文件夾時觸發

    public delegate void CopyFileEventHandler(long lngHad, long lngCount, string SourceFile ,string AimFile);
    public event CopyFileEventHandler OnCopyFile;//定義一個事件,在Copy文件時觸發

    public delegate void WorkOverEventHandler();//定義一個委託
    public event WorkOverEventHandler WorkOvered;//定義一個事件,在Copy文件完成時觸發

    public bool isDelete = false;
    public CopyDirectoryWorker(bool _isDelete, string _sourceDirectory, string _aimDirectory)
    {
        isDelete = _isDelete;
        SourceDirectory = _sourceDirectory;
        AimDirectory = _aimDirectory;
    }
    public string SourceDirectory;
    public string AimDirectory;
    /// <summary>
    /// 遞歸拷貝文件,把源目錄下所有文件和文件夾拷貝到目標目錄
    /// </summary>
    /// <param name="sourceDirectory">源路徑</param>
    /// <param name="aimDirectory">目標路徑</param>
    public void CopyFiles()
    {
        if (SourceDirectory.Substring(SourceDirectory.Length - 1, 1) == "/")
        {
            SourceDirectory = SourceDirectory.Substring(0, SourceDirectory.Length - 1);
        }
        if (!System.IO.Directory.Exists(AimDirectory))
        {
            System.IO.Directory.CreateDirectory(AimDirectory);
        }
        if (!System.IO.Directory.Exists(SourceDirectory))
             return ;
        sourceAllFile.Clear();
        RecursionCopyFiles(SourceDirectory, AimDirectory);
        RunCopyFiles();
        if (isDelete)
        {
            DeleteFile();
        }
        if (WorkOvered!=null)
        WorkOvered();
    }
    public void DeleteFile()
    {
        for (int i = 0; i < sourceAllFile.Count; i++)
        {
            if (sourceAllFile[i] != null && sourceAllFile[i].sFile != "")
                try
                {
                    System.IO.File.Delete(sourceAllFile[i].sFile);
                }
                catch { }
        }
        sourceAllFile.Clear();
    }
    class FileMove
    {
        public string sFile = "";
        public string aFile = "";
        public FileMove(string _sFile, string _aFile)
        {
            sFile = _sFile;
            aFile = _aFile;
        }
    }
    List<FileMove> sourceAllFile = new List<FileMove>();
    /// <summary>
    /// 二進制讀取文件,任何文件
    /// </summary>
    private void CopyFile(string SourceFile, string AimFile)
    {
        byte[] bytTemp = new byte[4096];//字節數組

        long lngHad = 0;
        long lngCount;
        int z = 5000;

        System.IO.FileStream fsSource = new System.IO.FileStream(SourceFile, System.IO.FileMode.Open, System.IO.FileAccess.Read, System.IO.FileShare.Read, 4);
        System.IO.BinaryReader bRead = new System.IO.BinaryReader(fsSource);
        bRead.BaseStream.Seek(0, System.IO.SeekOrigin.Begin);
        if (fsSource.Position > 0)
            fsSource.Position = 0;

        lngCount = fsSource.Length;

        if (System.IO.File.Exists(AimFile))
            System.IO.File.Delete(AimFile);

        System.IO.FileStream fsAim = new System.IO.FileStream(AimFile, System.IO.FileMode.CreateNew, System.IO.FileAccess.Write, System.IO.FileShare.Write, 4);
        System.IO.BinaryWriter bWrite = new System.IO.BinaryWriter(fsAim);

        while (z >= 4096)
        {
            z = (int)bRead.Read(bytTemp, 0, bytTemp.Length);
            bWrite.Write(bytTemp, 0, bytTemp.Length);

            lngHad += z;
            if (OnCopyFile!=null)
            {
                OnCopyFile(lngHad, lngCount, SourceFile, AimFile);
            }
        }
        //清理緩存區
        bWrite.Flush();
        bWrite.Close();
        bRead.Close();
        fsAim.Close();
        fsSource.Close();

    }

    /// <summary>
    /// 遞歸拷貝文件,把源目錄下所有文件和文件夾拷貝到目標目錄
    /// </summary>
    /// <param name="sourceDirectory">源路徑</param>
    /// <param name="aimDirectory">目標路徑</param>
    private bool RecursionCopyFiles(string sourceDirectory, string aimDirectory)
    {
        if (!System.IO.Directory.Exists(sourceDirectory) & !System.IO.Directory.Exists(aimDirectory))//
            return false;
        try
        {
            
            string[] directories = System.IO.Directory.GetDirectories(sourceDirectory);
            if (directories.Length > 0)
            {
                foreach (string dir in directories)
                {
                    string dirNew = dir.Replace(@"\", "/");
                    string dirTemp = dirNew.Substring(dirNew.LastIndexOf(@"/"));
                    RecursionCopyFiles(dirNew, aimDirectory + dirTemp);
                }
            }

            if (!System.IO.Directory.Exists(aimDirectory))
            {
                System.IO.Directory.CreateDirectory(aimDirectory);
            }
            string[] files = System.IO.Directory.GetFiles(sourceDirectory);
            if (files.Length > 0)
            {
                foreach (string file in files)
                {
                    string sourceFile = file.Replace(@"\", "/");
                    sourceAllFile.Add(new FileMove(sourceFile, aimDirectory));
                }
            }
            return true;
        }
        catch
        {
            return false;
        }
       
    }
    private void RunCopyFiles()
    {
        if (sourceAllFile.Count > 0)
        {
            for (int i = 0; i < sourceAllFile.Count; i++)
            {
                if (sourceAllFile[i] != null && sourceAllFile[i].sFile != "")
                {
                    try
                    {
                        string aimFile = sourceAllFile[i].aFile + sourceAllFile[i].sFile.Substring(sourceAllFile[i].sFile.LastIndexOf(@"/"));
                        if (OnGetProgress != null)
                        {
                            OnGetProgress(i + 1, sourceAllFile.Count, sourceAllFile[i].sFile, aimFile);
                        }
                        CopyFile(sourceAllFile[i].sFile, aimFile);
                    }
                    catch
                    {

                    }
                }
            }
        }
    }
}