Android-nRF-Blinky connect to multiple devices question

[mialo_5]

I have a dev question about using the nRF Blinky app as an example for listing and showing services for multiple BLE devices without having to individually select each one.

Currently the app ensures that the device is selected before you can view e.g. the button state.

I was wondering if it is possible to have the button state shown on the list of devices page (I have looked at the other related forum questions but not sure if enough detail has been provided or I have misunderstood what needs to be done)?

What I unsuccessfully attempted to do was to implement the BlinkManagerCallback on the ScannerViewModel and pass the model and activity to the DevicesAdapter. After connecting to a specific device it appears that all devices have the same "observer", i.e. if I press Button 1 on one device the other device (I only have two dev kit boards) updates with the same state. The other device appears to be blocked from receiving its own button service events. So to clarify, on the list of scanned devices page, I added some text that shows "pressed" and "released" just like the BlinkyViewModel does but when I press the Button on the dev board all listed scanned devices update their text whereas it should only be for the device whose button I pressed (I potentially added the code to the wrong place, I would have thought the observer goes in the OnBindViewHolder() in DevicesAdapter?).

Apologies for the long question, I hope that it makes sense.

Any help would be much appreciated.

[Aleksander Nowakowski]

Hi mialo_5,

nRF Blinky was designed to be very easy to use, understand and modify. We also use it as a base app for other our projects. Usually, a device would have a more complex API then the blinky example, which could indeed fit into a single row on a list, but because of that we have the second activity, where any UI can be quickly implemented. So, answering to your question, it is possible, but you would have to do it yourself.

To allow multiple connections, each callback has the `BluetoothDevice` object, based on which you know from which device you got the event, or where was the command sent. Sorry, I can't help you more.

You may also check the Proximity profile in nRF Toolbox, where it actually uses multiple connections. There we use a service instead of ViewModel.

Best Regards,

Aleksander

[mialo_5]

Hi Aleksander

Thank you for the reply.

I think I may be close to the solution but suspect that the issue I have is that the callback registered on the viewmodel actually needs to be registered for each view holder (device item) in some way.

I will look at the Proximity example although I believe I am close to the answer, just need some advice on the correct way to code this, if you or someone else is able to provide any insight.