i'm trying to develop a simple file encrypter-decrypter app. on android devices.user picks whichever file he/she wants and encrypt or decrypt it using aes.this process is allowed for internal storage but when i choose a file in sd card it causes an error i can't find a solution for a long time.
i have permissions in manifest.xml:
<uses-permission
android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission
android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission
android:name="android.permission.MANAGE_EXTERNAL_STORAGE"/>
also i ask user for runtime permissions(despite user allows permissions the result is "permission denied" error).
the error generated in th log is:
W/System.err: java.io.FileNotFoundException: storage/3962-3235/Download/dummyFileEncrypted.txt: open failed: EACCES (Permission denied)
where the error occurs in the encrypt function while the output file is being created, with line:
FileOutputStream outputStream=new FileOutputStream(outputFile);
as i said process works perfectly when i pick a file from internal storage.
any advice would be welcome. thanks in advance.
CodePudding user response：
Yes, micro sd cards are read only since Android KitKat.
Only one app specific directory is writable for your app.
Have a look at the second item returned by getExternalFilesDirs() for writable location.
Or use Storage Access Framework if you wanna write at other locations.
CodePudding user response：
You should check they, I recommend using framework.