How can I make my file writable in android sutdio app

Question

I'm working on an app on Android Studio and I would like to export data in an other app (gmail for example) when I click on a button.

This is my code:

 btnSurveyExportD = (Button) findViewById(R.id.btnSurveyExportD);
        btnSurveyExportD.setOnClickListener(new View.OnClickListener() {
            @RequiresApi(api = Build.VERSION_CODES.KITKAT)
            @Override
            public void onClick(View v) {
                Business x = new Business();

                String queryBeforEncryption = x.toRHSToolbox(s);
                queryBeforEncryption = queryBeforEncryption.replace("\n","\r\n");
                queryBeforEncryption = queryBeforEncryption.replace("'MV'","Null");
                queryBeforEncryption = queryBeforEncryption.replace("' '","Null");
                queryBeforEncryption = queryBeforEncryption.replace("'_'","Null");
                queryBeforEncryption = queryBeforEncryption.replace("'-9'","Null");
                queryBeforEncryption = queryBeforEncryption.replace("=-9.0","=Null");
                queryBeforEncryption = queryBeforEncryption.replace("=-9.00","=Null");
                queryBeforEncryption = queryBeforEncryption.replace("=-9","=Null");

                //String query = queryBeforEncryption;
                String query = x.NWEncryption(queryBeforEncryption,key);

                File file   = null;
                File root   = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM);
                if (root.canWrite()){
                    File dir    =   new File (root.getAbsolutePath() + "/QueryToDatabase");
                    dir.mkdirs();
                    file   =   new File(dir, "DataMobileRHS_" + s.getSite().toString() + ".rhs" );
                    FileOutputStream out   =   null;
                    try {
                        out = new FileOutputStream(file);
                    } catch (FileNotFoundException e) {
                        e.printStackTrace();
                    }
                    try {
                        out.write(query.getBytes());
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                    try {
                        out.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }

                Uri u1  = FileProvider.getUriForFile(getApplicationContext(), BuildConfig.APPLICATION_ID + ".provider",root);



                    //if the user took no photos
                if(MobileRHS.survey.getAlbum_path()==null){
                    Intent sendIntent = new Intent(Intent.ACTION_SEND);
                    sendIntent.putExtra(Intent.EXTRA_SUBJECT, "Survey export files - " + s.getSite().toString());
                    sendIntent.putExtra(Intent.EXTRA_STREAM, u1);
                    sendIntent.setType("text/html");

                    startActivity(sendIntent);
                }
                    //else
                else{
                    Intent sendIntent = new Intent(Intent.ACTION_SEND_MULTIPLE);
                    sendIntent.putExtra(Intent.EXTRA_SUBJECT, "Survey export files - " + s.getSite().toString());
                    sendIntent.setType("*/*"); //all types are accepted
                    ArrayList<Uri> queryAndPhotos = new ArrayList<>();
                    queryAndPhotos.add(u1);     //the text file is added

                    File[]filesToSend = new File (MobileRHS.survey.getAlbum_path()).listFiles();
                    for (File i : filesToSend) {       //each photo is added
                        Uri uri = FileProvider.getUriForFile(getApplicationContext(), BuildConfig.APPLICATION_ID + ".provider", i);
                        queryAndPhotos.add(uri);
                    }

                    sendIntent.putParcelableArrayListExtra(Intent.EXTRA_STREAM, queryAndPhotos);

                    startActivity(sendIntent);
                }



            }
        });

For each export I tried, the if(root.canWrite()) condition is not respected, so the last lines are not executed. How can I make my file root writable?

Thank you for advance

Answer 1

I had the same problem with File.exists(). Solved it by using getExternalFilesDir().

So I would recommend changing

Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM);

to

Environment.getExternalFilesDir(Environment.DIRECTORY_PICTURES);

Not sure, that you have the same problem, but it's worth a try