Abstract: Controlling methods for handheld devices with a touch display unit are provided. The controlling method includes the steps of: detecting a sliding gesture on the touch display unit when the handheld device is locked; in response to the detected sliding gesture, displaying at least one indication data on the touch display unit, wherein the indication data includes an indication object and the indication object rotates/flips around a central axis of the touch display unit and a rotating/flipping status of the indication object indicates an unlocking status in response to a detected contact position corresponding to the sliding gesture; and determining whether to unlock the handheld device according to the rotating/flipping status of the indication object.