Send data from your Arduino with Serial.println(), Serial.print() or Serial.write() in 9600 baud rate. Receive data with Serial.read().
Toggle between hex and ascii by clicking on received/sent data.
Let your own Android application receive data from Arduino by listening to the "primavera.arduino.intent.action.DATA_RECEIVED" intent. This intent will contain the "primavera.arduino.intent.extra.DATA" byte array with the received data. Call getByteArrayExtra("primavera.arduino.intent.extra.DATA") to retrieve the data. Send data to Arduino from your application by broadcasting an intent with action "primavera.arduino.intent.action.SEND_DATA". Add the data to be sent as byte array extra "primavera.arduino.intent.extra.DATA".