Why on onDeviceDiscovered the type is BluetoothDeviceEvent but when print the result is different?

[ValentinOsvaldo]

Hello

I have tried to use the onDeviceDiscovered function to save the devices as it finds them, but the type of the parameter returned by the callback is BluetoothDeviceEvent but when I print the result to the console, it returns something like this:

{
  "address": "example",
  "deviceClass": {
    "majorClass": 256,
    "deviceClass": 256
  },
  "extra": {
    "rssi": -81
  },
  "bonded": false,
  "id": "example",
  "name": "Totalplay"
}

I notice that there is an interface called BluetoothNativeDevice, very similar to what the onDeviceDiscovered listener prints. Is this really the type of value that it returns as a parameter in the listener?

As another question, I see that in types like BluetoothDevice there is the rssi as the value of the interface, but it is really printed normally within the value of extra. Is there something that makes it change?

Thanks for your help :D

[kenjdavidson]

1. You are correct, it looks like

   react-native-bluetooth-classic/android/src/main/java/kjd/reactnative/bluetooth/receiver/DiscoveryReceiver.java

   Line 52 in f47d8ff

   NativeDevice found = new NativeDevice(device);

   is actually creating a BluetoothNativeDevice, looks like this is a typing error. In the interim you can:

a) Attempt to just use event as BluetoothNativeDevice and see if it works.
b) Fix the issue and open a PR for it.

The response from that should actually be, something like:

BluetoothDeviceEvent: {
  eventType: BLUETOOTH_DEVICE,
  device: {
     address: ...
     etc...
  }
}

To match the rest of the event data.

3. This looks like another issue, the rssi is only in the extra map, I don't think it's ever placed within the main object. Although I don't think it really matters. For backward compatibility the line https://github.com/kenjdavidson/react-native-bluetooth-classic/blob/f47d8ff1d979321606f7474ec472319ba6d244c4/android/src/main/java/kjd/reactnative/bluetooth/receiver/DiscoveryReceiver.java#L53C23-L53C23 can be updated to set it in both places.

It would also need to be added to the Java version of NativeDevice in order to do so.

[ValentinOsvaldo]

I want to create a PR but to fix this typed issue there are to modify the https://github.com/kenjdavidson/react-native-bluetooth-classic/blob/main/src/BluetoothModule.ts#L484?

[kenjdavidson]

That line just returns the created subscription, it doesn't really do much with regards to the object returned from the subscription listener/handler.

[ValentinOsvaldo]

While I was changing my code I decided to try some use cases like connecting while the device is already connected but I noticed that it gives me this error

0

This is my code:

const connectDevice = (device: BluetoothNativeDevice): Promise<void> => {
    return new Promise(async (resolve, reject) => {
      try {
        const connectionSuccess = await RNBluetoothClassic.connectToDevice(
          device.address,
          {
            connectionType: 'binary',
            delimiter: '\r\n',
          },
        );

        if (!connectionSuccess)
          throw new Error(`Error al intentar conectar ${device.name}`);

        const readDevice = RNBluetoothClassic.onDeviceRead(
          device.address,
          onReceiveData,
        );

        const onDisconnect = RNBluetoothClassic.onDeviceDisconnected(
          (event: any) => {
            readDevice.remove();
            onDisconnect.remove();

            dispatch(removeDevice(event.address));

            ToastAndroid.show(`${event.name} se ha desconectado`, 3000);
          },
        );

        dispatch(
          addListener({
            address: device.address,
            listener: readDevice,
          }),
        );

        dispatch(setConnectedDevice(device));
        resolve();
      } catch (error) {
        reject(error);
      }
    });
  };

The connectToDevice method return a object, BluetoothDevice's connect method returns either true or false. How would I catch these exceptions?

[kenjdavidson]

Your screenshot and question are a little confusing:

• The screenshot shows an exception being thrown while attempting to set onReadDevice to a device which the native module doesn't have in it's connected devices collection. The error should have been caught in your catch(error) at the bottom, since you are wrapping the onReadDevice within that try/catch block.
• The reason behind this is that device.connect() you already have the device, so there is no reason to return the BluetoothDevice from that, a true/false seems acceptable. RNBluetoothClassic.connectToDevice(address) needs to return the full BluetoothDevice so that you can start working with it (if you choose) or you can choose not to and just keep the address for use. I tried to leave the option to use static methods or instance methods up to the developer.

I would say use the appropriate method for what you want to do?

[ValentinOsvaldo]

Sorry if my question is confusing...

My problem is the error on the screenshot doesn't catch the error because the connectToDevice method returns a object, I mean the request is success, so I want to catch the error but the object does not say anything to catch the error (in case the device is connected to another). In the connect method of BluetoothDevice returns a boolean, that helps me detect whether to continue with the process or not.

[ValentinOsvaldo]

I find other way to prevent the error:

await RNBluetoothClassic.connectToDevice(device.address, {
  connectionType: 'binary',
  delimiter: '\r\n',
});

const isConnect = await RNBluetoothClassic.isDeviceConnected(
  device.address,
);

if (!isConnect)
  throw new Error(`Failed to connect device ${device.name}`);

[kenjdavidson]

I'm still not sure why either:

• connectToDevice won't work, as it will either a) return a device or b) throw an exception if it cannot connect.

const device = await RNBluetoothClassic.connectToDevice(device.address, {
  connectionType: 'binary',
  delimiter: '\r\n',
});

• connect which would be done by using the connect method, which you've seen

const device = getBondedDevices().find(address -> address == "the address"); // or something else
const connected = device.connect();
if (connected).... 
else ....

As mentioned, the exception you're throwing is from attempting to onDeviceRead when the device is not connected. So you should have either gotten a connection exception or a false from the two above methods.