外部存储访问权限（～Android 11）

Android 12之后系统就不允许自由访问外部存储了，只能访问指定的外部存储存储，例如：context.getExternalFilesDir(Environment.type)下的外部存储，或者其他/Android/data/data下的外部存储。

<!-- Without this folders will be inaccessible in Android-11 and above devices -->

<uses-permission android:name="android.permission.MANAGE_EXTERNAL_STORAGE" />

<!-- Without this entry storage-permission entry will not be visible under app-info permissions list Android-10 and below -->

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" android:maxSdkVersion="29" tools:ignore="ScopedStorage" />

<!-- Without this entry the folders will remain in-accessible in Android-10, even if WRITE_EXTERNAL_STORAGE as above is present. --><application android:requestLegacyExternalStorage="true" />

文件访问权限申请

老规矩了，访问外部存储前需要申请权限。

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {      

val intent = Intent()       

intent.action = Settings.ACTION_MANAGE_APP_ALL_FILES_ACCESS_PERMISSION       

val uri: Uri = Uri.fromParts("package", this.packageName, null)       

intent.data = uri       

startActivity(intent)   

} else {       

val intent = Intent(Settings.ACTION_APPLICATION_SETTINGS)       

resultLauncher.launch(intent) 

 }

Android R以下申请权限

    var resultLauncher = registerForActivityResult(ActivityResultContracts.StartActivityForResult()) { result ->

     PermissionUtil.requestPermissionStorage(this, Const.REQUEST_PERMISSION_STORAGE)

    }

    val PERMISSIONS_STORAGE = arrayOf(READ_EXTERNAL_STORAGE, WRITE_EXTERNAL_STORAGE)

    fun requestPermissionStorage(activity: Activity, requestCode: Int): Boolean {

        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.R) {

            if (!checkPermissionsAuth(activity, PERMISSIONS_STORAGE)) {

                val deniedPermissions = getDeniedPermissions(activity, PERMISSIONS_STORAGE).toTypedArray()

                ActivityCompat.requestPermissions(activity, deniedPermissions, requestCode)

                return false

            }

        }

        return true

    }

Android12后文件访问

此时不需要申请权限了，可以直接访问。如果你要分享就需要添加FileProvider配置。

    val appDocDir = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {

        appContext.getExternalFilesDir(Environment.DIRECTORY_DOCUMENTS)!!

    } else {

        Environment.getExternalStorageDirectory()

    }

参考

WRITE_EXTERNAL_STORAGE when targeting Android 10