Android kotlin：即使在授予权限后也获得 EACCES（权限被拒绝）答案

【问题标题】：Android kotlin: Getting EACCES (Permission denied) even after giving permissionsAndroid kotlin：即使在授予权限后也获得 EACCES（权限被拒绝）
【发布时间】：2022-01-01 08:54:28
【问题描述】：

我正在开发一个 Android 应用，但在权限处理方面遇到了问题（API lvl 30，Android 版本 11）

我尝试按照此处的步骤操作：https://developer.android.com/training/permissions/requesting.html

当使用“checkSelfPermission()”函数时，看起来我有必要的权限，但是当我尝试写入文件时，我得到了显示在这篇文章底部的日志中的错误。

这是我的代码：

class FilesActivity : AppCompatActivity() {



val requestPermissionLauncher =
    registerForActivityResult(ActivityResultContracts.RequestPermission()) { isGranted: Boolean ->
        if (isGranted) {
            Log.d("access granted", isGranted.toString())

        } else {
            Log.d("access granted", isGranted.toString())
        }
    }


private lateinit var binding: ActivityFilesBinding

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)




    requestPermissions()

检查权限的方法如下：

    private fun requestPermissions() {
    when {
        ContextCompat.checkSelfPermission(
            this,
            Manifest.permission.WRITE_EXTERNAL_STORAGE
        ) == PackageManager.PERMISSION_GRANTED -> {
            Log.d("Permission","Already granted")
        }
        else -> {
            requestPermissionLauncher.launch(
                Manifest.permission.WRITE_EXTERNAL_STORAGE
            )
        }
    }
}

我得到权限提示，在授予权限后我尝试下载文件。下载文件的代码位于回收站视图的适配器类中。

                    try{
                    if(ContextCompat.checkSelfPermission(
                        mContext,
                        Manifest.permission.WRITE_EXTERNAL_STORAGE
                    ) == PackageManager.PERMISSION_GRANTED) {
                        val myFile = File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS),file.getFilename()!!)
                        val fileRef = Firebase.storage.getReferenceFromUrl(file.getUrl()!!)

                        fileRef.getFile(myFile).addOnSuccessListener {
                            // Local temp file has been created
                            Toast.makeText(mContext,"File downloaded to Downloads Dir.",Toast.LENGTH_LONG).show()
                        }.addOnFailureListener {
                            Toast.makeText(mContext,it.toString(),Toast.LENGTH_LONG).show()
                        }
                    }

                } catch(e :Error){
                    Toast.makeText(mContext,e.toString(),Toast.LENGTH_LONG).show()
                }

我不确定，我做错了什么。也许这里有人可以帮助我。提前致谢

编辑：我的 AndroidManifest.xml 看起来像这样：

<?xml version="1.0" encoding="utf-8"?>

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="com.google.android.c2dm.permission.RECEIVE" />

<application
    android:allowBackup="true"
    android:icon="@drawable/round_logo_app"
    android:label="@string/app_name"
    android:roundIcon="@drawable/app_logo_round"
    android:supportsRtl="true"
    android:requestLegacyExternalStorage="true"
    android:theme="@style/Theme.app">
    <activity android:name=".UserRatingsActivity"></activity>


    <activity
        android:name=".ui.myFiles.FilesActivity"
        android:label="@string/title_activity_files"
        android:theme="@style/Theme.StuddyV0_1.NoActionBar" />
    <activity android:name=".Register" />
    <activity android:name=".EnterCourses" />
    <activity
        android:name=".MainActivity"
        android:label="@string/title_activity_main" />
    <activity android:name=".LoginActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>

    <service
        android:name=".PushNotifications.FirebaseService"
        android:permission="com.google.c2dm.permission.SEND">
        <intent-filter>
            <action android:name="com.google.firebase.MESSAGING_EVENT" />
            <action android:name="com.google.android.c2dm.intent.RECEIVE" />
        </intent-filter>
    </service>
    <service
        android:name=".NotificationsPckg.MyFirebaseMessaging"
        android:enabled="true"
        android:exported="true">
        <intent-filter>
            <action android:name="com.google.firebase.MESSAGING_EVENT" />
        </intent-filter>
    </service>
</application>

在我手机的设置中，我可以看到该应用有权访问存储。

编辑：它可以在模拟器中运行，但不能在真实手机上运行。 (银河s20)

日志如下所示：

E/FileDownloadTask: Exception occurred during file write.  Aborting.
java.io.FileNotFoundException: /storage/emulated/0/Download/SKE_Labor.pdf: open failed: EACCES (Permission denied)
    at libcore.io.IoBridge.open(IoBridge.java:492)
    at java.io.FileOutputStream.<init>(FileOutputStream.java:236)
    at java.io.FileOutputStream.<init>(FileOutputStream.java:186)
    at com.google.firebase.storage.FileDownloadTask.processResponse(FileDownloadTask.java:147)
    at com.google.firebase.storage.FileDownloadTask.run(FileDownloadTask.java:228)
    at com.google.firebase.storage.StorageTask.lambda$getRunnable$7$StorageTask(StorageTask.java:1072)
    at com.google.firebase.storage.-$$Lambda$StorageTask$q9YBoR_A8LB-JxTCx8JRQvabaZs.run(Unknown Source:2)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
    at java.lang.Thread.run(Thread.java:923)
 Caused by: android.system.ErrnoException: open failed: EACCES (Permission denied)
    at libcore.io.Linux.open(Native Method)
    at libcore.io.ForwardingOs.open(ForwardingOs.java:166)
    at libcore.io.BlockGuardOs.open(BlockGuardOs.java:254)
    at libcore.io.ForwardingOs.open(ForwardingOs.java:166)
    at android.app.ActivityThread$AndroidOs.open(ActivityThread.java:8494)
    at libcore.io.IoBridge.open(IoBridge.java:478)
    at java.io.FileOutputStream.<init>(FileOutputStream.java:236) 
    at java.io.FileOutputStream.<init>(FileOutputStream.java:186) 
    at com.google.firebase.storage.FileDownloadTask.processResponse(FileDownloadTask.java:147) 
    at com.google.firebase.storage.FileDownloadTask.run(FileDownloadTask.java:228) 
    at com.google.firebase.storage.StorageTask.lambda$getRunnable$7$StorageTask(StorageTask.java:1072) 
    at com.google.firebase.storage.-$$Lambda$StorageTask$q9YBoR_A8LB-JxTCx8JRQvabaZs.run(Unknown Source:2) 
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167) 
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641) 
    at java.lang.Thread.run(Thread.java:923) 
E/StorageException: StorageException has occurred.
    An unknown error occurred, please check the HTTP result code and inner exception for server response.
     Code: -13000 HttpResult: 200
    /storage/emulated/0/Download/SKE_Labor.pdf: open failed: EACCES (Permission denied)
    java.io.FileNotFoundException: /storage/emulated/0/Download/SKE_Labor.pdf: open failed: EACCES (Permission denied)
        at libcore.io.IoBridge.open(IoBridge.java:492)
        at java.io.FileOutputStream.<init>(FileOutputStream.java:236)
        at java.io.FileOutputStream.<init>(FileOutputStream.java:186)
        at com.google.firebase.storage.FileDownloadTask.processResponse(FileDownloadTask.java:147)
        at com.google.firebase.storage.FileDownloadTask.run(FileDownloadTask.java:228)
        at com.google.firebase.storage.StorageTask.lambda$getRunnable$7$StorageTask(StorageTask.java:1072)
        at com.google.firebase.storage.-$$Lambda$StorageTask$q9YBoR_A8LB-JxTCx8JRQvabaZs.run(Unknown Source:2)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
        at java.lang.Thread.run(Thread.java:923)
     Caused by: android.system.ErrnoException: open failed: EACCES (Permission denied)
        at libcore.io.Linux.open(Native Method)
        at libcore.io.ForwardingOs.open(ForwardingOs.java:166)
        at libcore.io.BlockGuardOs.open(BlockGuardOs.java:254)
        at libcore.io.ForwardingOs.open(ForwardingOs.java:166)
        at android.app.ActivityThread$AndroidOs.open(ActivityThread.java:8494)
        at libcore.io.IoBridge.open(IoBridge.java:478)
        at java.io.FileOutputStream.<init>(FileOutputStream.java:236) 
        at java.io.FileOutputStream.<init>(FileOutputStream.java:186) 
        at com.google.firebase.storage.FileDownloadTask.processResponse(FileDownloadTask.java:147) 
        at com.google.firebase.storage.FileDownloadTask.run(FileDownloadTask.java:228) 
        at com.google.firebase.storage.StorageTask.lambda$getRunnable$7$StorageTask(StorageTask.java:1072) 
        at com.google.firebase.storage.-$$Lambda$StorageTask$q9YBoR_A8LB-JxTCx8JRQvabaZs.run(Unknown Source:2) 
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167) 
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641) 
        at java.lang.Thread.run(Thread.java:923) 
E/StorageException: StorageException has occurred.
    An unknown error occurred, please check the HTTP result code and inner exception for server response.
     Code: -13000 HttpResult: 200
    /storage/emulated/0/Download/SKE_Labor.pdf: open failed: EACCES (Permission denied)
    java.io.FileNotFoundException: /storage/emulated/0/Download/SKE_Labor.pdf: open failed: EACCES (Permission denied)
        at libcore.io.IoBridge.open(IoBridge.java:492)
        at java.io.FileOutputStream.<init>(FileOutputStream.java:236)
        at java.io.FileOutputStream.<init>(FileOutputStream.java:186)
        at com.google.firebase.storage.FileDownloadTask.processResponse(FileDownloadTask.java:147)
        at com.google.firebase.storage.FileDownloadTask.run(FileDownloadTask.java:228)
        at com.google.firebase.storage.StorageTask.lambda$getRunnable$7$StorageTask(StorageTask.java:1072)
        at com.google.firebase.storage.-$$Lambda$StorageTask$q9YBoR_A8LB-JxTCx8JRQvabaZs.run(Unknown Source:2)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
        at java.lang.Thread.run(Thread.java:923)
     Caused by: android.system.ErrnoException: open failed: EACCES (Permission denied)
        at libcore.io.Linux.open(Native Method)
        at libcore.io.ForwardingOs.open(ForwardingOs.java:166)
        at libcore.io.BlockGuardOs.open(BlockGuardOs.java:254)
        at libcore.io.ForwardingOs.open(ForwardingOs.java:166)
        at android.app.ActivityThread$AndroidOs.open(ActivityThread.java:8494)
        at libcore.io.IoBridge.open(IoBridge.java:478)
        at java.io.FileOutputStream.<init>(FileOutputStream.java:236) 
        at java.io.FileOutputStream.<init>(FileOutputStream.java:186) 
        at com.google.firebase.storage.FileDownloadTask.processResponse(FileDownloadTask.java:147) 
        at com.google.firebase.storage.FileDownloadTask.run(FileDownloadTask.java:228) 
        at com.google.firebase.storage.StorageTask.lambda$getRunnable$7$StorageTask(StorageTask.java:1072) 
        at com.google.firebase.storage.-$$Lambda$StorageTask$q9YBoR_A8LB-JxTCx8JRQvabaZs.run(Unknown Source:2) 
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167) 
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641) 
        at java.lang.Thread.run(Thread.java:923)

编辑：回到这个问题后，我注意到，它只发生在 .pdf 文件中。其他所有内容均已正确下载并保存。

【问题讨论】：

如果您进入应用程序的设置，您可以查看您是否确实具有写入权限。 `
Android kotlin: Getting EACCES (Permission denied) .. 不清楚该文件是哪个文件。用于在您的设备上创建文件或用于 Firebase 中的文件。
这是我在下载之前创建的文件，用于将下载写入文件。 “验证我的文件”
val myFile = File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS),file.getFilename()!! 你创建了一个 File 实例。那不会创建文件。所以不会导致访问失败。请调查。
我以为会是这一行：“fileRef.getFile(myFile).addOnSuccessListener”导致错误。顺便说一句：它在模拟器中工作，但在我的真实手机上却没有

标签： android firebase kotlin storage

【解决方案1】：

Extends ActivityCompat.OnRequestPermissionsResultCallback 在 FilesActivity 类中不可用。

class FilesActivity : AppCompatActivity() , ActivityCompat.OnRequestPermissionsResultCallback {
}

您需要为 requestPermissionLauncher 定义调用 ActivityCompat.OnRequestPermissionsResultCallback 接口。

示例代码：

class MainActivity : AppCompatActivity(), ActivityCompat.OnRequestPermissionsResultCallback {


private val requestPermissionLauncher = registerForActivityResult(
        ActivityResultContracts.RequestPermission()
    ) { isGranted: Boolean ->
        if (isGranted) {
            // Permission has been granted. Start camera preview Activity.

                startCamera()

        } else {
            // Permission request was denied.
            requestPermissions()
        }
    }



override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)

    requestPermissions()


}

private fun requestPermissions() {
    if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA)
        == PackageManager.PERMISSION_GRANTED) {
        // Permission has been granted. Start camera preview Activity.
        startCamera()

    } else  requestPermissionLauncher.launch(Manifest.permission.CAMERA)
}


private fun startCamera() {
    val intent = Intent(MediaStore.ACTION_IMAGE_CAPTURE)
    startActivity(intent)
}

}

https://github.com/harunkor/requestPermissionLauncherSample

【讨论】：

正如目前所写，您的答案尚不清楚。请edit 添加其他详细信息，以帮助其他人了解这如何解决所提出的问题。你可以找到更多关于如何写好答案的信息in the help center。
感谢您的回答。当我在 FilesActivity 中下载文件时，它确实有效。但是我想用 FilesAdapter 类中的一个函数来下载文件，用于上述的回收器视图。我仍然在那里检查权限，但没有运气。
这毫无意义。您在哪里询问并获得许可并不重要。它将在整个应用程序的整个生命周期内有效。只有在获得许可后才能下载和编写。你可以在第二天这样做，以确保安全 ;-)。
感谢您的所有帮助，但在我已经发布的适配器类的代码中，我在下载前检查了权限。我在那里做错了吗？我知道这没有意义。