Why does my File.mkdirs() always return false?

Question

I am following the code snippet given here in this guide. The following lines (particurly the last if block in the following lines) are presenting a problem:

File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
              Environment.DIRECTORY_PICTURES), "MyCameraApp");

    // This location works best if you want the created images to be shared
    // between applications and persist after your app has been uninstalled.

    // Create the storage directory if it does not exist
    if (! mediaStorageDir.exists()){
        if (! mediaStorageDir.mkdirs()){
            Log.d("MyCameraApp", "failed to create directory");
            return null;
        }
    }

The problem is that return null; in the snippet above is always executed.

This means that mediaStorageDir.mkdirs() always returns false.

The question is why and what can I do to fix it?

@Solace if its 23 than [refer](http://stackoverflow.com/a/38226786/3117966) this — Nisarg, Jul 22 '16 at 08:46
please make sure you have written write permission in android manifest file — Jayakrishnan, Jul 22 '16 at 08:48
@Nisarg I had set `6.0` while creating the project but i have tried to run it on `4.4` emulator, and `4.1` real device. Minimum is `8` — Solace, Jul 22 '16 at 08:55
@Nisarg But I DO have WRITE_EXTERNAL_STORAGE and READ_EXTERNAL_STORAGE permissions declared in Manifest. :s — Solace, Jul 22 '16 at 09:22
@Solace Yes I was searching for that only, runtime permissions dont work here because you are running on 4.1 and found [this](http://stackoverflow.com/a/13032360/3117966) it might be the case — Nisarg, Jul 22 '16 at 09:48
@Nisarg But same is the case with Genymotion emulator (running 4.4) :s — Solace, Jul 22 '16 at 10:05
Using `mediaStorageDir.exists()`, as you can see in the question. — Solace, Jul 22 '16 at 10:14
@Nisarg No. :( I added read permissions in addition to write permissions in android. I tried the runtime permissions method which you had suggested. I also tried replacing `mkdir` instead of `mkdirs`. Nothing worked so far. — Solace, Jul 22 '16 at 11:36
@Solace Yup its strange, I saw many links nothing found particularly why this is happening — Nisarg, Jul 22 '16 at 11:46

score 0 · Answer 1 · answered Jul 22 '16 at 08:49

0

do you have set

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

in your Manifest file?

answered Jul 22 '16 at 08:49

Richard R

873
6
20

No, I just have `WRITE_EXTERNAL_STORAGE` – Solace Jul 22 '16 at 08:53
1

You might need both. Give it a try. – Richard R Jul 22 '16 at 08:57
you don't need both. You have write permission, the read permission is "built-in" – Budius Jul 22 '16 at 09:34

Why does my File.mkdirs() always return false?

1 Answers1