Help Service and Activity connection

[gabyft45ol]

Hello,

I have a device that measure the heart rate, and send the value to my application with bluetooth LE. I created a class AnDeviceBluetoothLE, that control the bluetooth. In my Activity I have an object device from this class, and functions like device.getConnexionState() or device.setMode(int m) are used in this Activity. When the device get a new value of heart rate, it display on Activity with Activity.setData(...).

Everything works, but when I close the application the bluetooth connection stop. So I want to create a Service with my object device, and establish a communication between my Service and my Activity:

-My Activity ask the Service the connection state, the Service give the value obtain with device.getConnexionState(), and the Activity can continue the others operations with the value.
for example, I currently have that in my Activity:

 if (device.getConnectionState() == AnDeviceBluetoothLE.STATE_CONNECTED) {...}

So if I put the device in a Service and use BroadcastManager to send demand and receive value, will my Activity wait to receive the value before doing the if?

-The Service must send the measurements, but only when the Application is opened.
How the Service can know if the Activity is opened or not?


Thanks.