lens i e the camera lens and the touch panel face toward the same roughly the same direction referred to as the u2018 front u2019 direction accordingly when the focal length of the subject is shorter then a certain focal length it can be presumed that the subject is approaching the camera lens and the touch panel in step s 124 it is determined that the mobile phone should operate in a communication mode that is it is determined that a user is making a call or answering a call when the u2018 receive u2019 button step s 104 or the u2018 call u2019 button step s 102 is pressed and an object is approaching the touch panel referring to fig1 d in step s 131 the touch panel is locked thus the virtual buttons on the touch panel cannot be activated to avoid accidental triggering of functions in step s 132 the light measurement is determined when the touch panel has been locked in step s 133 it is determined whether the light measurement is lower than a preset illumination level step s 134 is performed when the light measurement is not lower than the preset illumination level step s 1331 is performed when the light measurement is lower than the preset illumination level in step s 1331 an exposure compensation process is performed the exposure compensation process can be a software exposure compensation process to increase the exposure of the camera or a hardware exposure compensation process to provide more light by a flash or lamp in step s 134 the touch panel is unlocked the method then returns to step s 105 in step s 135 a focal.