Arduino Game Android Bluetooth JoyStick Control

Hello there. I have a question about game control in Arduino when using a mobile phone. Recently I have added an Android BlueDuino App to my game demo. It works, but is not quite flexible for my game (I control a car object in 2D matrix made of LEDS and have to press 4 joystick buttons). Is there anything in Android which mimics a real joystick? I need something that I can control with my thumb finger while not releasing it and changing to any direction including diagonals.

Hello. Thank you very much. I have already found the similar app called
Arduino Bluetooth Controlled Joystick APK made by Uncia Robotics. I looks and works almost the same like the one you have offered.