Why do i need write permission external storage to delete a file?

Question

My question is why i need this permission when i'm trying to delete a file from the sdcard, as the permissions says 'Write' it doesn't write anything to the sdcard when i try to delete something so why is this required?

I tried removing the permission, but without it nothing works.

WRITE_EXTERNAL_STORAGE is a dangerous permission which i need to include in my privacy policy and i'm not sure how to explain this.

My permissions

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

My code to delete a file

if (getActivity() != null) {
                        try {
                            treeUri = storageUtil.loadTreeUri();
                            if (!treeUri.equals("")) {
                                deleteFile(Uri.parse(treeUri), file);
                                Main.songs.deleteFile(getActivity(), songList.get(position).getData());
                                Main.songs.reScan(getActivity());
                                songList = Main.songs.getSongs();
                                //Send broadcast to update adapters
                                Intent intent = new Intent(Constants.ACTIONS.BROADCAST_UPDATE_ADAPTER2);
                                getActivity().sendBroadcast(intent);

                                if (!songList.isEmpty()) {
                                    allSongsAdapter.updateList(songList);
                                }

                            } else if (treeUri.equals("")) {
                                ((MainActivity) getActivity()).getSDCardAccess();
                                Toast.makeText(getActivity(), "First select directory with music files and try again.", Toast.LENGTH_LONG).show();
                            }
                        } catch (Exception e) {
                            Toast.makeText(getActivity(), "Something went wrong!", Toast.LENGTH_SHORT).show();
                        }
                        dialog.dismiss();
}

deleteFile method

private void deleteFile(Uri uri, File file){
    if (getActivity() != null){
        Intent intent = new Intent(Constants.ACTIONS.BROADCAST_UPDATE_PANEL_STATE);
        LocalBroadcastManager.getInstance(getActivity()).sendBroadcast(intent);

    }
    if (file.delete()){
        Log.i(TAG,"internal delete!");
        return;
    }
    if (getActivity() != null && file.exists()) {
        DocumentFile pickedDir = DocumentFile.fromTreeUri(getActivity(), uri);
        String filename = file.getName();
        try {
            getActivity().getContentResolver().takePersistableUriPermission(uri, Intent.FLAG_GRANT_READ_URI_PERMISSION | Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
        } catch (SecurityException e) {
            Log.e(TAG, "SecurityException caught when deleting FilePath!", e);
        }
        Log.d(TAG, "fileName: " + filename);
        if (pickedDir != null) {
            DocumentFile documentFile = pickedDir.findFile(filename);
            if (documentFile != null && documentFile.exists()) {
                if (documentFile.delete()) {
                    Log.i(TAG, "Delete successful");
                } else {
                    Log.i(TAG, "Delete unsuccessful");
                }
            }
        }
    }
}

This is the code i used from another post on here

Android SAF (Storage Access FrameWork): Get particular file Uri from TreeUri

This question is based on a faulty premise. Being able to delete files is obviously a dangerous permission, since it can delete data that the user does not want to be deleted. If your phone warned you when apps could write files, but allowed apps to delete files as they pleased, would you even remotely trust that operating system to care for your security and well-being? — nanofarad, Sep 21 '19 at 14:26

score 1 · Answer 1 · answered Sep 21 '19 at 14:20

1

There are two types of permissions. 1. To read content (read only access) 2. To modify content (read & write access)

Write access/permission is about modifying content on the disc.

answered Sep 21 '19 at 14:20

Mukund Desai

100
2

score 0 · Answer 2 · answered Sep 21 '19 at 16:05

0

Deleting a file is the same concept as issuing an rm via commandline in Unix. This unlinks the file (modifying the disk) which requires the write permission.

https://unix.stackexchange.com/a/10884

answered Sep 21 '19 at 16:05

Brandon McAnsh

992
8
18

score 0 · Answer 3 · answered Sep 21 '19 at 16:13

0

Deleting a file in any OS is the modification of master file table reference, which informs the OS where the file was located.

answered Sep 21 '19 at 16:13

Sagar Das

128
9

Why do i need write permission external storage to delete a file?

3 Answers3