CODEWITHSUNDEEP
javaandroidandroid-studiobluetooth-lowenergy
persiaprince
persiaprince

Reputation: 85

onDescriptorWrite() never called in BluetoothGattCallback

I would like to subscribe to multiple characteristics. Currently I'm doing this (mostly successfully) by using a timer between calling each writeDescriptor(descriptor). I would like to instead do this by utilizing the onDescriptorWrite() callback, but it is never being called.

I have the following call back.

private final BluetoothGattCallback mGattCallback = new BluetoothGattCallback() {
    @Override
    public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
        String intentAction;
        if (newState == BluetoothProfile.STATE_CONNECTED) {
            intentAction = ACTION_GATT_CONNECTED;
            mConnectionState = STATE_CONNECTED;
            broadcastUpdate(intentAction);
            Log.i(TAG, "Connected to GATT server.");
            // Attempts to discover services after successful connection.
            Log.i(TAG, "Attempting to start service discovery:" +
                    mBluetoothGatt.discoverServices());


        } else if (newState == BluetoothProfile.STATE_DISCONNECTED) {
            intentAction = ACTION_GATT_DISCONNECTED;
            mConnectionState = STATE_DISCONNECTED;
            Log.i(TAG, "Disconnected from GATT server.");
            broadcastUpdate(intentAction);
        }
    }

    @Override
    public void onServicesDiscovered(BluetoothGatt gatt, int status) {
        if (status == BluetoothGatt.GATT_SUCCESS) {
            broadcastUpdate(ACTION_GATT_SERVICES_DISCOVERED);
        } else {
            Log.w(TAG, "onServicesDiscovered received: " + status);
        }
    }

    @Override
    public void onCharacteristicRead(BluetoothGatt gatt,
                                     BluetoothGattCharacteristic characteristic,
                                     int status) {
        if (status == BluetoothGatt.GATT_SUCCESS) {
            broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic);
        }
    }

    @Override
    public void onCharacteristicChanged(BluetoothGatt gatt,
                                        BluetoothGattCharacteristic characteristic) {
        broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic);
    }
    @Override
    public void onDescriptorWrite(BluetoothGatt gatt, BluetoothGattDescriptor descriptor, int status) {
        super.onDescriptorWrite(gatt, descriptor, status);
        Log.d("onDescWrite", "yes");
        if(characteristics_with_notifications_or_indications.size() > 0) {
            characteristics_with_notifications_or_indications.remove(0);
            subscribeToCharacteristics();
        }
    }
};

It's initialized in my connect function.

mBluetoothGatt = device.connectGatt(this, false, mGattCallback);

This is my descriptor write

mBluetoothGatt.setCharacteristicNotification(characteristic, enabled);
BluetoothGattDescriptor descriptor = characteristic.getDescriptor(
            UUID.fromString(CESGattAttributes.CLIENT_CHARACTERISTIC_CONFIG));

descriptor.setValue(BluetoothGattDescriptor.ENABLE_INDICATION_VALUE);
mBluetoothGatt.writeDescriptor(descriptor);

I would like to know when I'm done doing a writeDescriptor() via the callback so I can subscribe to another characteristic. However, even when I've successfully subscribed to a characteristic and am receiving valid data, onDescriptorWrite() still does not get called.How can I get onDescriptorWrite() to be called?

Upvotes: 2

Views: 2426

Answers (1)

persiaprince
persiaprince

Reputation: 85

So I figured out the problem. The callback function wasn't being called because I had a list of all the characteristics which had notify/indicate properties. However, before I would write to my descriptor I would check for certain UUIDs. Well, I wasn't checking for one of the characteristics because I wasn't using it, and it happened to be one of the first ones on the list! So, I would never even write to the descriptor for the callback to be called.

Upvotes: 0

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