An electronic device includes resistor, a pointer, a measuring module, a calculating module, and a display module. The resistor has a reference point corresponding with a reference direction. The resistor defines a circle. The pointer has a pointing terminal contacting the resistor at a contacting point corresponding with a reference direction. The pointer is pivotablely mounted about a centre of the circle. The pointer is aligned with the magnetic field of the Earth, and the measuring module measures the voltage between the contacting point and the reference point. The calculating module calculates an angle between the current direction and the reference direction according to the voltage between the contacting point and the reference point of the resistor. The display module displays corresponding direction information according to the angle.