Exception ‘open failed: EACCES (Permission denied)’ on Android

Google has a new feature on Android Q: filtered view for external storage. A quick fix for that is to add this code in the AndroidManifest.xml file:

<manifest ... >
    <!-- This attribute is "false" by default on apps targeting Android Q. -->
    <application android:requestLegacyExternalStorage="true" ... >
     ...
    </application>
</manifest>

You can read more about it here: https://developer.android.com/training/data-storage/use-cases

Edit: I am starting to get downvotes because this answer is out of date for Android 11. So whoever sees this answer please go to the link above and read the instructions.