code: public void setPicker(GVRPicker picker)
      {
          if (mPicker != null)
          {
              mPicker.setEnable(false);
          }
          mPicker = picker;
      }
docs: Establishes which picker should generate touch events for the keyboard.
  By default, a new picker is created on startup which is attached
  to the camera and follows the user's gaze. This function lets you
  associate the keyboard with a specific controller or a custom picker.
  <p>
  In order for a picker to work with the keyboard, {@link GVRPicker.EventOptions}
  SEND_TO_HIT_OBJECT, SEND_TO_LISTENERS and SEND_TOUCH_EVENTS must be
  enabled. These are enabled by default for pickers attached to cursor
  controllers. If you provide a custom picker and you do not enable
  these options, you will not get the proper keyboard behavior.
  @param picker GVRPicker used to generate touch events
  @see GVRCursorController#getPicker()
  @see org.gearvrf.GVRPicker.EventOptions