Dropbox should respond to Android Intent.ACTION_SEND

Hello, i have a problem with my app. When i try to share a .zip file with dropbox it doesn´t work. This is my code that should allow to share with gmail, dropbox, gdrive, etc.:

This code works for gmail and gdrive but it doesn´t work for dropbox.Can you help me?, what is the problem?

Intent emailIntent = new Intent(Intent.ACTION_SEND);

      String aEmailList[] = { " };
      String aEmailCCList[] = { "};
      String aEmailBCCList[] = { " };

      emailIntent.putExtra(Intent.EXTRA_EMAIL, aEmailList);
      emailIntent.putExtra(Intent.EXTRA_CC, aEmailCCList);
      emailIntent.putExtra(Intent.EXTRA_BCC, aEmailBCCList);
      boolean plus = Tienda.personalizarEmailAdquirido(actividad);
      emailIntent.putExtra(Intent.EXTRA_SUBJECT,plus?
              PersonalizacionTextos.getTextoEmail(actividad,PersonalizacionTextos.ASUNTO_BACKUP):
              actividad.getString(R.string.txsubjectbackup));
      emailIntent.putExtra(Intent.EXTRA_TEXT, plus?
              PersonalizacionTextos.getTextoEmail(actividad,PersonalizacionTextos.MENS_BACKUP):
              actividad.getString(R.string.txbodybackup));
      ExternalStorageState eSs = new ExternalStorageState(actividad.getString(R.string.app_directoryname));
      if(eSs.isPresentString(eSs.getPathWithoutCreate("backup"))){
          try {
              File directorioToFind = new File(eSs.getPathWithoutCreate("backup"));
              String ficheroZipeado = eSs.getPath("backup.zip","zip");
              NZipCompresser nZc = new NZipCompresser(directorioToFind,ficheroZipeado);
              nZc.compress();
              String uri = "file://" + ficheroZipeado;
              emailIntent.putExtra(Intent.EXTRA_STREAM, Uri.parse (uri));
              emailIntent.setType("application/zip");

          } catch (Exception e) {
              NotificationSender nM = new NotificationSender(actividad,"Error en zip","Error en zip,"+e.getMessage());
              nM.sendNotification();
          }
          actividad.startActivity(Intent.createChooser(emailIntent,"));