Trying to create a file in Android open failed EROFS Read-only file system

Question

This line   final FileOutputStream outputStream   new FileOutputStream name     results in a FileNotFoundException with the message being  2ozjfFQzwv  open failed  EROFS  Read-only file system  where  2ozjfFQzwv  is what I passed as the name of the file   I have tried this with and without the WRITE INTERNAL STORAGE permission  How do I create this file for writing   Alternatively  I just want to be able to give an image to a new activity  and it is too large to serialize it in an extra  Is there an easier way than writing it to a file then reading from it again  All the questions on here seem to be about writing to an SD card  which I don t want to do because many people don t have SD card slots

User · Answer

To use internal storage for the application, you don't need permission, but you may need to use: File directory = getApplication().getCacheDir(); to get the allowed directory for the app.

Or:
getCashDir(); <-- should work
context.getCashDir(); (if in a broadcast receiver)
getDataDir(); <--Api 24

User · Answer

try using the permission of WRITE EXTERNAL STORAGE You should use that whether there is an external card or not   This works well for me   path   Environment getExternalStoragePublicDirectory                  Environment DIRECTORY MOVIES   File file   new File path        fname     and places my files in the appropriate folder

User · Answer

If anyone getting this in unit instrumentation testing  make sure you call getFilesDir   on the app context  not the test context  i e  use   Context appContext   getInstrumentation   getTargetContext   getApplicationContext      not   Context appContext   InstrumentationRegistry getContext

User · Answer

Here is simple sample from android developer   Basically  you can write a file in the internal storage like this    String FILENAME    hello file   String string    hello world     FileOutputStream fos   openFileOutput FILENAME  Context MODE PRIVATE   fos write string getBytes     fos close

User · Answer

As others have mentioned  app on Android can t write a file to any folder the internal storage but their own private storage  which is under  data data PACKAGE NAME     You should use the API to get the correct path that is allowed for your app   read this

User · Answer

Adding     lt uses-permission android name  android permission WRITE EXTERNAL STORAGE    gt    lt uses-permission android name  android permission READ EXTERNAL STORAGE    gt    in manifest and using same as Martin   path   Environment getExternalStoragePublicDirectory Environment DIRECTORY MOVIES    File file   new File path        fname     It worked

User · Answer

Google have restricted write access to the external sdcard  From API 19 there is a framework called Storage Access Framework which allows you the set up  contracts  to allow write access   For further info   Android - How to use new Storage Access Framework to copy files to external sd card

User · Answer

I have tried this with and without the WRITE INTERNAL STORAGE permission    There is no WRITE INTERNAL STORAGE permission in Android      How do I create this file for writing    You don t  except perhaps on a rooted device  if your app is running with superuser privileges  You are trying to write to the root of internal storage  which apps do not have access to   Please use the version of the FileOutputStream constructor that takes a File object  Create that File object based off of some location that you can write to  such as    getFilesDir    called on your Activity or other Context  getExternalFilesDir    called on your Activity or other Context    The latter will require WRITE EXTERNAL STORAGE as a permission      Is there an easier way than writing it to a file then reading from it again    You can temporarily put it in a static data member      because many people don t have SD card slots    SD card slots  are irrelevant  by and large  99  of Android device users will have external storage -- the exception will be 4  year old devices where the user removed their SD card  Devices manufactured since mid-2010 have external storage as part of on-board flash  not as removable media

[android] Trying to create a file in Android: open failed: EROFS (Read-only file system)

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