Trying to read in subscription callback fails

Version

Tell us which versions you are using:

• react-native-ble-manager: 3.3.0
• react-native: 0.44.0
• Android, Nexus 5X

Expected behaviour

Doing a read in the callback of a subscription should be succesful

Actual behaviour

The read always fails, so I have to retry it in the catch statement with a timeout, then it works. It seems that the BLE is “busy” and thus is not ready to read yet. I don’t know if it is the peripheral or the Android BLE manager that is not ready yet.

Steps to reproduce

1. Subscribe to a characteristic
2. In the callback for the subscribe event, read the same characteristic

Stack trace and console log

It just says, read failed.

[whitedogg13]

Hi @marcosinigaglia , I might spot a possible cause.

In line 404 @ Peripheral.java, we have codes like this:

if (gatt.writeDescriptor(descriptor)) {
   ...
   callback.invoke();
   ...
}

This call flow uses writeDescriptor in a synchronous manner. However, from Android doc https://developer.android.com/reference/android/bluetooth/BluetoothGatt.html, we can see the writeDescriptor just returns whether the operation is initialied and the actual result comes from onDescriptorWrite callback.

I will try to fix this and report it later 😃

[vikeri]

@whitedogg13 that’s great! Well done!