Cannot write to external storage if the application does not restart after granting permission

Question

The application cannot write to external memory on Android 6.0 (I am testing an emulator), even after WRITE_EXTERNAL_STORAGE was provided at runtime; if the application will not be killed and restarted.

Snippet from AndroidManifest.xml

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

build.gradle

 android { compileSdkVersion 23 buildToolsVersion "23.0.1" defaultConfig { ...... minSdkVersion 15 targetSdkVersion 23 } 

Whenever I need to write to external storage (for backup), I check if I have permission.

  if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M && getActivity().getBaseContext().checkSelfPermission(Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) { requestPermissions(new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, PERMISSION_REQUEST_RW_EXTERNAL_STORAGE); mPendingAction = PendingAction.Backup; } else { BackupRestoreService.startBackup(getActivity().getBaseContext()); } 

I also have

  @Override public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) { super.onRequestPermissionsResult(requestCode, permissions, grantResults); Log.d("SettingsActivity", "grantResultsLength: " + grantResults.length); if (requestCode == PERMISSION_REQUEST_RW_EXTERNAL_STORAGE) { Log.d("SettingsActivity", "grantResultsLength: " + grantResults.length); if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) { switch (mPendingAction) { case Backup: BackupRestoreService.startBackup(getActivity().getBaseContext()); mPendingAction = PendingAction.None; break; case Restore: break; default: } } else { Toast.makeText(getActivity(), "Permission denied", Toast.LENGTH_SHORT).show(); } } } 

When permission is granted by the user, the following code

 File file = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS), DIR_MY_PORTFOLIO); if (!file.mkdirs()) Log.d("Backup", "Unable to create directories"); final String outputFilename = new SimpleDateFormat("'Backup'-yyyyMMdd-hhmmss'.mpb'", Locale.US).format(new Date()); File outputFile = new File(getBackupStorageDir(), outputFilename); Log.d("Backup", "Can write to file: " + outputFile.canWrite()); Log.d("Backup", "File exists: " + outputFile.exists()); 

produces

  in.whoopee.myportfolio D/Backup: Unable to create directories in.whoopee.myportfolio D/Backup: Can write to file: false in.whoopee.myportfolio D/Backup: File exists: false in.whoopee.myportfolio W/System.err: java.io.FileNotFoundException: /storage/09FD-2F0C/Download/My Portfolio/Backup-20151011-051318.mpb: open failed: EACCES (Permission denied) 

If, after obtaining permission, the application is killed and restarted, everything will be perfect, and the backup file will be created in external storage.

Please suggest what I am doing wrong.

Answer 1

Add the following line to the onRequestPermissionsResult () method after successfully resolving the permission.

 android.os.Process.killProcess(android.os.Process.myPid()); 

Edit: Make sure you set the target version of sdk to 23. if you already did this and it doesn't work (or you don't want to set it to 23) than you can go with this solution (killing the application process).

Answer 2

Try to imitate a new device (e.g. 6.0 x86_64 with Google api's). I had the same problem and decided to run it on a different emulator.