Android 11 - Creating app-specific directory on external storage

user_11117526 0
Viewed 1604

Recently, I'm trying to migrate my application from SDK-29 to SDK-30. And one thing I concerned the most is scoped storage.

I saw on official document that says "On Android 11 (API level 30) and higher, apps cannot create their own app-specific directory on external storage."

So I tried it out to create my own directory inside external storage and write a new file to it. The code looks like this :

// creating new directory under external storage
val appDir = File(applicationContext.getExternalFilesDir(null), "play")
appDir.mkdir()

// writing new file under my own directory
val newFile = File(appDir.absolutePath, "test.jpg")
val outputStream = FileOutputStream(newFile)
val inputStream = resources.openRawResource(R.drawable.ic_launcher_foreground)
val data = byteArrayOf()
inputStream.read(data)
outputStream.write(data)
inputStream.close()
outputStream.close()

I expected this code will crash but it works. I find the file at the given path. So, I'm a little confused the meaning of that note.

What do Google means with "cannot create their own app-specific directory on external storage"?

scoped-storage android
2 Answers

They are referring to creating arbitrary directories off of the external storage root (e.g., Environment.getExternalStorageDirectory().

getExternalFilesDir() and similar methods on Context are fine solutions to use instead!

user_1151450

To create app-specific directory on external storage but off root.

private fun createDir(directoryName: String): File? {
        val file = File(applicationContext.getExternalFilesDir("/"),directoryName)
        if (!file?.mkdirs())
            print("Volume : " + "Directory not created")

        return file
    }

Note: For that does not required any storage permission.

To create app-specific directory on external storage in root.

Note: This is only work for Android 11.

Request for All files access from the user:

  1. Declare the MANAGE_EXTERNAL_STORAGE permission in the manifest.
  2. Use the ACTION_MANAGE_ALL_FILES_ACCESS_PERMISSION intent action to direct users to a system settings page where they can enable the following option for your app: Allow access to manage all files.
  3. To determine whether your app has been granted the MANAGE_EXTERNAL_STORAGE permission, call Environment.isExternalStorageManager().

Write code on OnCreate Method:

if (!isExternalStorageReadable()) return

if (!Environment.isExternalStorageManager()) {
            val intent = Intent(Settings.ACTION_MANAGE_APP_ALL_FILES_ACCESS_PERMISSION)
            intent.addCategory("android.intent.category.DEFAULT")
            intent.data = Uri.parse(String.format("package:%s", applicationContext.packageName))
            startActivityForResult(intent, 20)
        } else {
            createDir("ddddd")
        }

Declare two functions outside from OnCreate:

private fun isExternalStorageReadable(): Boolean {
        return Environment.getExternalStorageState() in
                setOf(Environment.MEDIA_MOUNTED, Environment.MEDIA_MOUNTED_READ_ONLY)
    }

private fun createDir(directoryName: String): File? {
        val file = File(Environment.getExternalStoragePublicDirectory("/"),directoryName)
        if (!file?.mkdirs())
            print("Volume : " + "Directory not created")

        return file
    }
user_30186270
Related