A graphical user interface (GUI) may be displayed on a display unit in an apparatus which may include a tactile sensor unit. When a contact by a user is detected at the tactile sensor unit, a control unit may receive a contact detection signal therefrom. Based on the contact detection signal, the control unit may determine a contact pattern and may then display the GUI corresponding to the contact pattern. The GUI may be displayed and modified depending on the location and pressure of contacts by a user's manipulating fingers. Therefore, a user can manipulate the apparatus without any inconvenience or accidental touches.