A mobile device is a pocket-sized computing device with a touchscreen. Using a touchscreen as an Input/Output device, many applications, known as Apps, have been developed to interact with humans in as natural a way as possible. In most cases, the user interactive interface for mobile applications is designed to allow interaction with users via multiple buttons on a touchscreen. Conventionally, to press a button on a touchscreen, a user uses one hand when the mobile device is small. However, recently, touchscreens for mobile devices have become larger than those of traditional hand-held devices. The Samsung Note, the ASUS Phone Pad and the iPad mini are examples. Because manufactures have enlarged the size of mobile devices, users use an entire hand to interact with applications, which is difficult. In addition, in some situations, users cannot use a pair of hands to interact with applications. To resolve this issue, using the Android system, this study proposes two novel user interactive interfaces, which guarantee that users can interact with applications using one hand, even if the touchscreen is large. In the demonstration, one-handed operation of the mobile device is shown to be easy.