Android - Never get notification

RE: Android - Never get notification

Parita — Mon, 29 Jul 2019 13:19:47 GMT

getValue() is showing null value. Is there any process to get the byte value from nRF52 ble module

RE: Android - Never get notification

Christopher — Tue, 26 Jul 2016 11:53:51 GMT

Here are the required steps to enable a characteristic notifications (very similar for indications):

Get the characteristic from the connected device:

BluetoothGattCharacteristic char = gatt.getService(serviceUuid).getCharacteristic(charUuid);

You should maybe check if the characteristic has a CCCD and has the notification property.

Then, enable the notifications or indications:

gatt.setCharacteristicNotification(char, true);

Finally, write to the CCCD to enable notifications:

BluetoothGattDescriptor desc = char.getDescriptor(CCCD_UUID); desc.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE); boolean success = gatt.writeDescriptor(desc);

You can check the result of the GATT writeDescriptor operation to be sure it has been sent. Then, you can wait for the asynchronous onDescriptorWrite callback to be sure the value has been written to the remote device.

Be aware that it is not possible to queue GATT operations with the Android BLE stack. If the radio/stack is busy, you must wait on the operation callback before sending a new operation.

Nordic provides some Android source code examples on Github, have a look here for instance. You can see an example with a queue of operations.

RE: Android - Never get notification

Troud — Mon, 20 Jun 2016 09:42:49 GMT

Yes i've done that. I also try with the flag indication, but nothing... I've resolve the problem by threading the write. Each writing operation is made by a new thread, and with that solution i get notification.

RE: Android - Never get notification

Vyacheslav Lebets — Sun, 19 Jun 2016 22:39:25 GMT

Hi. First, You should enable notification sending 1 to cccd descriptor of desired characteristic.