How to create a file on Android Internal Storage?

Question

I want to save a file on internal storage into a specific folder. My code is:

File mediaDir = new File("media");
if (!mediaDir.exists()){
   mediaDir.createNewFile();
   mediaDir.mkdir();

}
File f = new File(getLocalPath());
f.createNewFile();
FileOutputStream fos = new FileOutputStream(f);
fos.write(data);
fos.close();

getLocalPath returns /data/data/myPackage/files/media/qmhUZU.jpg but when I want to create the media folder I'm getting the exception "java.io.IOException: Read-only file system". Any ideas how to write my files on internal phone storage in in folder media? Thanks.

If you want to create the path /media, you cannot - not unless the phone is rooted. Apps are not allowed to write into the root folder. — Seva Alekseyev, Feb 16 '11 at 14:24
a file I was able to create but a folder not. is there a restriction for folders? — Buda Gavril, Feb 16 '11 at 14:30
For those that need a full tutorial: http://chrisrisner.com/31-Days-of-Android--Day-23%E2%80%93Writing-and-Reading-Files — Jared Burrows, Dec 24 '12 at 19:40

score 23 · Answer 1 · answered Feb 16 '11 at 15:07

23

You should use ContextWrapper like this:

ContextWrapper cw = new ContextWrapper(context);
File directory = cw.getDir("media", Context.MODE_PRIVATE);

As always, refer to documentation, ContextWrapper has a lot to offer.

answered Feb 16 '11 at 15:07

Audrius

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I didn't understand one thing, how is it different from calling the same method of the original context? – Malcolm May 24 '11 at 10:30
1

ContextWrapper is just a proxy to the original context. The benefit here is that you can subclass ContextWrapper to achieve some custom behavior, so that say getDir() actually returns some other (non-standard) directory. You are right that one can use Context directly tho'. – Audrius May 24 '11 at 12:53

score 2 · Answer 2 · answered Feb 16 '11 at 14:02

2

You should create the media dir appended to what getLocalPath() returns.

answered Feb 16 '11 at 14:02

Lucas S.

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1

no, it's not a solution because the file doesn't exists and I want to create it – Buda Gavril Feb 16 '11 at 14:15
4

No, it is a solution - you have to create the folder before you can write files within it. – Chris Stratton Oct 29 '13 at 15:08

Tyler · Answer 3 · 2011-08-10T18:31:22.510

I was getting the same exact error as well. Here is the fix. When you are specifying where to write to, Android will automatically resolve your path into either /data/ or /mnt/sdcard/. Let me explain.

If you execute the following statement:

File resolveMe = new File("/data/myPackage/files/media/qmhUZU.jpg");
resolveMe.createNewFile();

It will resolve the path to the root /data/ somewhere higher up in Android.

I figured this out, because after I executed the following code, it was placed automatically in the root /mnt/ without me translating anything on my own.

File resolveMeSDCard = new File("/sdcard/myPackage/files/media/qmhUZU.jpg");
resolveMeSDCard.createNewFile();

A quick fix would be to change your following code:

File f = new File(getLocalPath().replace("/data/data/", "/"));

Hope this helps

This is replacing a very bad idea with a slightly less bad idea, but still unwise - ordinarily application should just not be assuming absolute paths, but rather discovering the applicable ones at runtime using the provided APIs. — Chris Stratton, Oct 29 '13 at 15:09

score 0 · Answer 4 · answered Mar 19 '18 at 11:01

Write a file

When saving a file to internal storage, you can acquire the appropriate directory as a File by calling one of two methods:

getFilesDir()

      Returns a File representing an internal directory for your app.

getCacheDir()

     Returns a File representing an internal directory for your 
     app's temporary cache files.
     Be sure to delete each file once it is no longer needed and implement a reasonable 
     size limit for the amount of memory you use at any given time, such as 1MB.

Caution: If the system runs low on storage, it may delete your cache files without warning.

score -3 · Answer 5 · edited Apr 25 '12 at 21:20

-3

Hi try this it will create directory + file inside it

File mediaDir = new File("/sdcard/download/media");
if (!mediaDir.exists()){
    mediaDir.mkdir();
}

File resolveMeSDCard = new File("/sdcard/download/media/hello_file.txt");
resolveMeSDCard.createNewFile();
FileOutputStream fos = new FileOutputStream(resolveMeSDCard);
fos.write(string.getBytes());
fos.close();

System.out.println("Your file has been written");

edited Apr 25 '12 at 21:20

Tyler

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answered Apr 19 '12 at 23:53

6

/sdcard and internal storage (which is what this question was about) are two totally different things. – lenik Apr 20 '12 at 01:35
yeah, the question was about something else – Paranoid Android Apr 19 '13 at 12:30
2

This is not about external storage! – Tomask Sep 13 '16 at 21:08

How to create a file on Android Internal Storage?

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