[Help]: Descriptor uuid is too short

[leijdekkers]

Requirements

• [X] I've looked at the README 'Common Problems' section

Have you checked this problem on the example app?

No

FlutterBluePlus Version

1.28.10

Flutter Version

latest

What OS?

Android

OS Version

ios 16

Bluetooth Module

na

What is your problem?

It looks like the descriptor value is too short. So i have a specific bluetooth device with the following characteristic and descriptor values

Characteristic: 02a6c0d1-0451-4000-b000-fb3210111989 Descriptor: 00002902-0000-1000-8000-00805f9b34fb

I do the following to get the characteristic and descriptor

// Get the specific characteristic BluetoothCharacteristic? characteristic = service?.characteristics.firstWhereOrNull((element) => element.characteristicUuid.toString() == "02a6c0d1-0451-4000-b000-fb3210111989");

// Get the descriptor BluetoothDescriptor? descriptor = characteristic?.descriptors.firstWhereOrNull((d) => d.uuid.toString() == "00002902-0000-1000-8000-00805f9b34fb");

When I look at characteristic?.descriptors values, it shows me the following:

remoteId = {DeviceIdentifier} FC:A8:9B:A0:C8:2E
serviceUuid = {Guid} 02a6c0d0-0451-4000-b000-fb3210111989
characteristicUuid = {Guid} 02a6c0d1-0451-4000-b000-fb3210111989
descriptorUuid = {Guid} 2902

The descriptorUuid only returns “2902” and it should be “00002902-0000-1000-8000-00805f9b34fb”

In older FlutterBluePlus versions it was working correctly. So not sure what has been changed but it is not correct currently.

Thanks Peter

Logs

na

[chipweinberger]

The descriptorUuid only returns “2902” and it should be “00002902-0000-1000-8000-00805f9b34fb”

yes there were changes related to this. we now return short names, aka 16-bit uuid, where possible.

2902 & 00002902-0000-1000-8000-00805f9b34fb are the same!

2909 is a "short name", part of the ble spec. they are equivalent. a 16 bit uuid can be converted to a 128 bit uuid by adding "-0000-1000-8000-00805f9b34fb" to the end.

if you want to compare the full name as a sting, use guid.uuid128

however it is more proper to compare Guid to Guid. this will do the conversions for you.

if (desc.uuid == Guid("2902"))

or

if (desc.uuid == Guid("00002902-0000-1000-8000-00805f9b34fb"))

^these are equivalent!