Cannot read a file from external storage even though permission is granted

Question

I am using Android Studio and a virtual device (Nexus 5 S on x86).

I am trying for tests purposes to read a binary file from external storage.

When I connect to the device with 'adb shell' to the device, I can find the file in /storage/emulated/0

In my test activity, I just put this:

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    final String filename = "basse-normandie.map";

    final File file = new File(Environment.getExternalStorageDirectory()
                      .getAbsolutePath(), filename);
    Log.i("FileTests", "file is '"+file.getAbsolutePath()+"'");
    Log.i("FileTests", "file exists: "+file.exists());
    file.setReadable(true);
    Log.i("FileTests", "app can read file: "+file.canRead());

}

and in the manifest I put

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

I guess WRITE_EXTERNAL_STORAGE is not useful though.

In the logcat window, I get this:

06-25 19:03:46.648 5107-5107/org.airforce_one.filetests I/FileTests: file is '/storage/emulated/0/basse-normandie.map'
    file exists: true
    app can read file: false

and I can't find what I'm doing wrong... Every page I've looked on the net tells me to give the permissions, but no other hints...

http://stackoverflow.com/questions/32635704 – Mike M. Jun 25 '18 at 23:03 — Mike M., Jun 25 '18 at 23:03

SafalFrom2050 · Answer 1 · 2018-06-25T18:56:39.047

1

Remove final in the line

 File file = new File(Environment.getExternalStorageDirectory()
                  .getAbsolutePath(), filename);

And change

file.setReadable(true, false); //the second parameter is specify if the permission is for OwnerOnly

edited Jun 25 '18 at 18:56

answered Jun 25 '18 at 17:22

SafalFrom2050

687
6
12

You need to set readable permission like "file.setReadable(true,false)" because your above method sets readable permission for OwnerOnly. – SafalFrom2050 Jun 25 '18 at 18:54
Thanks for this precision, I didn't know about it. However, even with this modification, 'file.setReadable(true,false)' gives a value of false, so my app doesn't have the permission to set the file to readable-by-all, and the subsequent 'file.canRead()' still gives false as an answer... – user3605616 Jun 25 '18 at 19:24

score 0 · Answer 2 · edited Nov 16 '18 at 02:05

0

I had the exact same issue with a .map file with

file.setReadable(true, false);

solved it.

edited Nov 16 '18 at 02:05

Stephen Rauch

47,830
31
106
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answered Nov 16 '18 at 01:38

Kann Nix

13
2

Cannot read a file from external storage even though permission is granted

2 Answers2