First thing you need is to know how to make the connection with the thermometer. I suppose that, since the device is paired to the smartphone, you only must to manage the connection as a server (On the android-phone). Here you got a summarize:
- Change Bluetooth permissions: http://developer.android.com/guide/topics/connectivity/bluetooth.html#Permissions
- Enable and set up the bluetooth: http://developer.android.com/guide/topics/connectivity/bluetooth.html#SettingUp
- Find the device: http://developer.android.com/guide/topics/connectivity/bluetooth.html#FindingDevices
- Connect with it: http://developer.android.com/guide/topics/connectivity/bluetooth.html#ConnectingAsAServer
- And manage the connection: http://developer.android.com/guide/topics/connectivity/bluetooth.html#ManagingAConnection
And last thing, I recommend you to pair the device before running the application, at the adjust menu of your mobilephone. Since that, follow the previous steps and all will be fine. If you have some doubt ask me, I had the same troubles about bluetooth connections with arduino and HC-06 bluetooth device
Hope it helps