Bluetooth Arduino Connection is the companion app for a project where Arduino Uno is connected to an Android device via a Bluetooth module. Using the app it is possibile to send command to Arduino in order to light some LED's and to receive the board status including the temperature measured by a sensor.
The project, including the app code, is described in details on http://www.instructables.com/id/Connect-Arduino-Uno-to-Android-via-Bluetooth/