set a TextField Componet to readonly

[Mehmet . Kaplankiran]

I want to set a TextField Componet to readonly. I have overriden isEnabled and 
onDisabled methods. but it did'nt work

      private TextField vehicleTypeField(final String id, final TBPosition 
position)
      {
        final TextField field = new TextField(id, vehicleTypeModel(position))
        {
          private static final long serialVersionUID = -7101271673345103957L;

          @Override
          public boolean isVisible()
          {
            return isVehicleTypeVisible();
          }

          @Override
          protected void onDisabled(final ComponentTag tag)
          {
            String vehicleType = "E";  //only for Test
            if (vehicleType.equalsIgnoreCase("E"))
              tag.put("readonly", "readonly");
          }

          @Override
          public boolean isEnabled()
          {
            // return position.getVehicleType().equalsIgnoreCase("E");
            // only for test
            String vehicleType = "E";
            return !vehicleType.equalsIgnoreCase("E");
          }

        };
        field.add(new ValueHelperOnDoubleClickBehavior(popupPanelVehicleType, 
HelperValues.VEHICLE_TYPES));
        return field;
      }


could you please help me.

best regards


Mehmet