Why the device will connect again when we diconnect from device?

RE: Why the device will connect again when we diconnect from device?

Hung Bui — Mon, 26 Jun 2017 13:16:44 GMT

I tested on an S8 running Android 7.0 If I force closed Spotify or uninstall it , the re-connection stopped.

I tried with notification running with 100Hz but saw no difference.

Could you send us your test firmware ?

RE: Why the device will connect again when we diconnect from device?

berniechen — Mon, 26 Jun 2017 10:04:11 GMT

hi Hung Bui I still have the reconnecting problem if I don't implement this workaround. And I also test pixel phone with custom image from AOSP(NMF26O), this image has minimum app installed, still have reconnecting issue. What the environments you test? Did you use Nordic Uart APK ? github.com/.../Android-nRF-UART Did you test your device with notify characteristic to inform the phone 100 times per second? Thanks your reply.

RE: Why the device will connect again when we diconnect from device?

Hung Bui — Fri, 23 Jun 2017 07:30:13 GMT

Hi berniechen ,

Thanks for sharing your workaround with us. It's still strange that you need to disable notification before you disconnect.

May I ask do you still have the reconnecting problem if you don't implement the workaround. In our test here our devices didn't have problem after we remove Spotify app.

Have you tried to test on a fresh phone with minimum app installed ? We are suspecting there could be an app that detect if there is notification receives from a device and then the device get disconnected it will try to re-connect again.

RE: Why the device will connect again when we diconnect from device?

berniechen — Thu, 22 Jun 2017 03:29:35 GMT

There is my solution at nRF UART APK.

if (mBluetoothAdapter == null || mBluetoothGatt == null) {
        Log.w(TAG, "BluetoothAdapter not initialized");
        return;
    }
    BluetoothGattService RxService = mBluetoothGatt.getService(RX_SERVICE_UUID);
    if(RxService != null) {
        BluetoothGattCharacteristic TxChar = RxService.getCharacteristic(TX_CHAR_UUID);
        BluetoothGattDescriptor descriptor = TxChar.getDescriptor(CCCD);
        descriptor.setValue(BluetoothGattDescriptor.DISABLE_NOTIFICATION_VALUE);

        mBluetoothGatt.writeDescriptor(descriptor);
    }
    Handler handler = new Handler();
    handler.postDelayed(new Runnable() {
        @Override
        public void run() {
            mBluetoothGatt.disconnect();
        }
    }, 1000);

at the function of disconnect(), We need disable descriptor first, and post delay 1 sec to disconnect() then close the gatt.

But I hope the bluetooth expert director me why the device will reconnect again when we turn on notify characteristic??? Thanks.

RE: Why the device will connect again when we diconnect from device?

berniechen — Wed, 21 Jun 2017 11:00:44 GMT

Hi, I force close Spotify on my Xeperia XC, and using nRF Connect to scanning device and connect to it, then I disconnect from device. It will not reconnect again. If I connect it and open CCCD enable, then the characteristic send me some values 100 times per sec, it will reconnect again after I disconnecting from device. If I disable the CCCD, then pressing the disconnect, it will not reconnect again. why..?

RE: Why the device will connect again when we diconnect from device?

MartinBL — Wed, 21 Jun 2017 09:21:19 GMT

What happens if you uninstall your app, connect to your device with nRF Connect, and disconnect again? Do you still experience that the phone keeps reconnecting by itself?

If it is something similar to the Spotify issue it shouldn't matter what app you use to connect. You just need to connect and disconnect once, with e.g. nRF Connect, and then Spotify (or maybe a different app) will continue the cycle in the background.

RE: Why the device will connect again when we diconnect from device?

berniechen — Wed, 21 Jun 2017 08:23:54 GMT

I test the google pixel with custom system image with no Spotify app, but it still has the same problem....

RE: Why the device will connect again when we diconnect from device?

MartinBL — Thu, 15 Jun 2017 17:31:45 GMT

We seem to have slightly different symptoms, but the solution presented here seems to work for me: Android BLE unexpectedly and repeatedly reconnects to peripheral.

Can you try to "Force Close" Spotify if you have it installed?

RE: Why the device will connect again when we diconnect from device?

berniechen — Thu, 15 Jun 2017 02:17:14 GMT

@Martin Børs-Lind

I haven't figured out the problem yet. And I think the one of solution is firmware. Device side can translate status to normal mode(don't try reconnect again) after received the signal of disconnect.
Indeed, mService.close() can't be comment. because I have two product. one of frequent of notify characteristic too fast, it will reconnect immediately after I disconnect and result in null object operation. so we need comment mService.close(). Another product still have reconnect issue, but the notify frequency is less than another product. I need un-comment mService.close() to release resource to let case of reconnection not occur.
Xperoa compact and Google Pixel

RE: Why the device will connect again when we diconnect from device?

MartinBL — Tue, 13 Jun 2017 12:07:48 GMT

Hi @berniechen. Have you made any progress on this? I have some similar issues, but haven't figured out the problem yet.

Is it so that after you have connected to your device once with your own app your phone keeps reconnecting by itself?
You have a workaround which is to remove mService.close() from your code?
What happens if you uninstall your app, connect to your device with nRF Connect, and disconnect again? Do you still experience that the phone keeps reconnecting by itself?
Have you tried this on more than one phone?

RE: Why the device will connect again when we diconnect from device?

Hung Bui — Tue, 06 Jun 2017 11:14:37 GMT

@Berniechen: I can't read what you paste, please put them in a text file and edit the question and put the file there. Don't you see that it's unreadable what you paste above.

Why would the phone reconnect ? In our code I don't think we have any reconnect. I don't think simply change the UUID cause the problem. Please try again with the stock example, then modify UUID and test.

RE: Why the device will connect again when we diconnect from device?

berniechen — Mon, 05 Jun 2017 06:10:52 GMT