现在有个需求，读写安卓系统的根目录下的文档
路径为
/storage/emulated/0/Documents/
在Unity PlayerSetting里有一个设置访问非持久化路径的设置
但是实际打包后发现还是访问不了。
解决方法
申请与配置方法
先自动生成一下AndroidManifest.xml，然后添加授权
csharp
<uses-permission android:name="android.permission.MANAGE_EXTERNAL_STORAGE" />MANAGE_EXTERNAL_STORAGE 是 Android 10（API 级别 29）引入的系统权限，允许应用访问和管理设备外部存储上的所有文件，但需用户显式授权。
授权方法
csharp
/// <summary>
/// 检查授权状态
/// </summary>
/// <returns></returns>
private bool HasExternalStoragePermission()
{
#if (!UNITY_EDITOR && UNITY_ANDROID)
using (var version = new AndroidJavaClass("android.os.Build$VERSION"))
{
if (version.GetStatic<int>("SDK_INT") >= 30)
{
using (var environment = new AndroidJavaClass("android.os.Environment"))
{
return environment.CallStatic<bool>("isExternalStorageManager");
}
}
}
#endif
return true;
}
/// <summary>
/// 唤醒授权
/// </summary>
private void RequestExternalStoragePermission()
{
#if (!UNITY_EDITOR && UNITY_ANDROID)
using (var version = new AndroidJavaClass("android.os.Build$VERSION"))
{
if (version.GetStatic<int>("SDK_INT") >= 30)
{
using (var unityPlayer = new AndroidJavaClass("com.unity3d.player.UnityPlayer"))
{
using (var currentActivity = unityPlayer.GetStatic<AndroidJavaObject>("currentActivity"))
{
using (var intent = new AndroidJavaObject("android.content.Intent"))
{
intent.Call<AndroidJavaObject>("setAction", "android.settings.MANAGE_APP_ALL_FILES_ACCESS_PERMISSION");
using (var uriClass = new AndroidJavaClass("android.net.Uri"))
{
using (var uri = uriClass.CallStatic<AndroidJavaObject>("parse", "package:" + currentActivity.Call<string>("getPackageName")))
{
intent.Call<AndroidJavaObject>("setData", uri);
}
}
currentActivity.Call("startActivity", intent);
}
}
}
}
}
#endif
}完整的测试代码
功能是要在安卓根目录的文档中，必须存在test.txt，没有就写入，有就读取。
（比如实现写入某个唯一密钥文件，用于激活软件）
csharp
public string path = "/storage/emulated/0/Documents/test.txt";
public Text mt;
void Start()
{
GetPermission();
CheckFileAndProcess();
}
private void OnApplicationFocus(bool focus)
{
if (focus)
{
GetPermission();
}
}
void GetPermission()
{
if (!HasExternalStoragePermission())
{
RequestExternalStoragePermission();
}
else
{
SceneManager.LoadSceneAsync(1);
}
}
private bool HasExternalStoragePermission()
{
#if (!UNITY_EDITOR && UNITY_ANDROID)
using (var version = new AndroidJavaClass("android.os.Build$VERSION"))
{
if (version.GetStatic<int>("SDK_INT") >= 30)
{
using (var environment = new AndroidJavaClass("android.os.Environment"))
{
return environment.CallStatic<bool>("isExternalStorageManager");
}
}
}
#endif
return true;
}
private void RequestExternalStoragePermission()
{
#if (!UNITY_EDITOR && UNITY_ANDROID)
using (var version = new AndroidJavaClass("android.os.Build$VERSION"))
{
if (version.GetStatic<int>("SDK_INT") >= 30)
{
using (var unityPlayer = new AndroidJavaClass("com.unity3d.player.UnityPlayer"))
{
using (var currentActivity = unityPlayer.GetStatic<AndroidJavaObject>("currentActivity"))
{
using (var intent = new AndroidJavaObject("android.content.Intent"))
{
intent.Call<AndroidJavaObject>("setAction", "android.settings.MANAGE_APP_ALL_FILES_ACCESS_PERMISSION");
using (var uriClass = new AndroidJavaClass("android.net.Uri"))
{
using (var uri = uriClass.CallStatic<AndroidJavaObject>("parse", "package:" + currentActivity.Call<string>("getPackageName")))
{
intent.Call<AndroidJavaObject>("setData", uri);
}
}
currentActivity.Call("startActivity", intent);
}
}
}
}
}
#endif
}
private void CheckFileAndProcess()
{
if (!HasExternalStoragePermission())
{
SetTextSafe("无文件访问权限，无法执行文件操作！");
RequestExternalStoragePermission();
return;
}
while (!File.Exists(path))
{
try
{
string directoryPath = Path.GetDirectoryName(path);
if (!Directory.Exists(directoryPath))
{
Directory.CreateDirectory(directoryPath);
Debug.Log("自动创建目录：" + directoryPath);
}
string writeContent = "HelloWorld";
File.WriteAllText(path, writeContent, System.Text.Encoding.UTF8);
Debug.Log("文件不存在，已自动写入：" + path + " 内容：" + writeContent);
}
catch (Exception ex)
{
SetTextSafe("文件写入失败，重试中：" + ex.Message);
}
}
try
{
string fileContent = File.ReadAllText(path, System.Text.Encoding.UTF8);
SetTextSafe("程序启动检测到文件，内容：\n" + fileContent);
}
catch (Exception ex)
{
SetTextSafe("文件存在但读取失败：" + ex.Message);
Debug.LogError("文件读取异常：" + ex.ToString());
}
}
public void ReadFileContentToText()
{
if (!HasExternalStoragePermission())
{
SetTextSafe("请先授予文件访问权限！");
RequestExternalStoragePermission();
return;
}
if (mt == null)
{
Debug.LogError("请在Inspector面板为mt赋值Text组件！");
return;
}
try
{
if (!File.Exists(path))
{
SetTextSafe("文件不存在：" + path);
return;
}
string fileContent = File.ReadAllText(path, System.Text.Encoding.UTF8);
SetTextSafe("文件内容：\n" + fileContent);
Debug.Log("文件读取成功：" + path);
}
catch (Exception ex)
{
SetTextSafe("读取失败：" + ex.Message);
Debug.LogError("文件读取异常：" + ex.ToString());
}
}
public void WriteHelloWorldToFile()
{
if (!HasExternalStoragePermission())
{
SetTextSafe("请先授予文件访问权限！");
RequestExternalStoragePermission();
return;
}
try
{
string directoryPath = Path.GetDirectoryName(path);
if (!Directory.Exists(directoryPath))
{
Directory.CreateDirectory(directoryPath);
Debug.Log("目录已创建：" + directoryPath);
}
string writeContent = "HelloWorld";
File.WriteAllText(path, writeContent, System.Text.Encoding.UTF8);
if (mt != null)
{
SetTextSafe("写入成功！\n路径：" + path + "\n内容：" + writeContent);
}
Debug.Log("文件写入成功：" + path);
}
catch (Exception ex)
{
if (mt != null)
{
SetTextSafe("写入失败：" + ex.Message);
}
Debug.LogError("文件写入异常：" + ex.ToString());
}
}
private void SetTextSafe(string content)
{
if (mt != null && !string.IsNullOrEmpty(content))
{
mt.text = content;
}
}验证
