Crear una aplicación para Android

Due lack of time, we need to request a freelance for completing this project. Technology experience requirements are: 1. Developer in Android [You can develop in Phonegap] 2. Developer with sensors [Sensor is Aprilbeacons iBeacons - not Eddystone because we need to use into iPhone too in the future.] Task to develop is: 1. Create a class that when the device entry into a beacons regions, returns the identificator of this beacons, always return most close [we are going to test with several beacons in same place]. Implements Observer design pattern for this class. 2. Envelop this class into an Background Activity [launched on device restart] that receive the identificator when device in on region. 3. Performance is very important so the code will be analysed for getting best performance.