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

[berniechen]

I modified the nordic uart apk from this website

github.com/.../Android-nRF-UART

and I do some revising below

MainActivity.java:
if (action.equals(WearableService.ACTION_GATT_DISCONNECTED)) {
    runOnUiThread(new Runnable() {
     public void run() {
     Log.d(tAg, "UART_DISCONNECT_MSG");
     mState = UART_PROFILE_DISCONNECTED;
     //mService.close(); <--- I comment this
     }
     });
 }

When I disconnect from device, I can see log on my phone Xperia X compact (android 7.0)

BluetoothGatt: cancelOpen() - device: F1:C1:E2:24:ED:57
BluetoothGatt: onClientConnectionState() - status=0 clientIf=5 device=F1:C1:E2:24:ED:57
BluetoothGatt: onClientConnectionState() - status=0 clientIf=5 device=F1:C1:E2:24:ED:57
BluetoothGatt: discoverServices() - device: F1:C1:E2:24:ED:57
BluetoothGatt: onSearchComplete() = Device=F1:C1:E2:24:ED:57 Status=0
BluetoothGatt: setCharacteristicNotification() - uuid: 6e400003-b5a3-f393-e0a9-e50e24dcca9e enable: true

I find It will connect again after I disconnect from the device and then do discoverServi

ce and finally disconnect, why???? The workaround method is uncomment the mService.close() to release the resource when MainActivity.java gets DISCONNECT broadcast.

Below is the screen shot of my phone(we only revised UUID for UartService, there are no revising at Uart apk). When I disconnect from device at 10:18:45 and then reconnect at 10:18:47 and then send one command(this device automatically notify data to apk per 3 second) and then finally disconnect.

Another product we develop is below, because it will reconnect, so the button still show Disconnect, not Connect, and we can't change button state anymore, because it has disconnect, we can't send disconnect command to it.

below is operate null pointer.

[berniechen]

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.

[berniechen]

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.