startNotification doesn't enable NOTIFY property

Version

Tell us which versions you are using:

• react-native-ble-manager v6.2.6
• react-native v0.53.0
• Android 7.0

Expected behaviour

When calling startNotification, as i can see from the native code (Android in particular, but i hope also iOS), the library should enable the NOTIFY char configuration descriptor value to 1 so the BLE device will start notifying data.

Actual behaviour

This doesn’t happen, and the BLE device stays with NOTIFY set to 0. If we enable first notify via another app then it works as it is already enabled.

Steps to reproduce

1. Connect to BLE device, retrieve services, make sure Notify is disabled by default in ble device
2. Call startNotification on any service/char which has notify disabled by default
3. No notifications incoming

Stack trace and console log

No error is thrown, no stacktrace either

Hope to get some help, thanks in advance!

[Girum]

If someone if still interested in this issue, here is a sample to enable multiple notifications on Android.

async startNotifications(deviceID) {
  try {
    await BleManager.startNotification(deviceID, ServiceDemo, Characteristic1);
    await BleManager.startNotification(device.id, ServiceDemo, Characteristic2);
    await BleManager.startNotification(device.id, ServiceDemo, Characteristic3);
  } catch (error) {
    warn('Could not start notifications for all characteristics:', error);
    // don't forget to throw the error again to reject the promise
    throw error;
  }
}

If you want to use the then style, you can do this instead.

startNotifications(deviceID) {
  return BleManager.startNotification(deviceID, ServiceDemo, Characteristic1)
    .then(() => BleManager.startNotification(deviceID, ServiceDemo, Characteristic2))
    .then(() => BleManager.startNotification(deviceID, ServiceDemo, Characteristic3))
    .catch(error => {
      warn('Could not start notifications for all characteristics:', error);
      // don't forget to throw the error again to reject the promise
      throw error;
    });
}

Hi! How can you render the notification data in the screen without load and "freeze"the screen because the re-render?

[drash-course]

If someone if still interested in this issue, here is a sample to enable multiple notifications on Android.

async startNotifications(deviceID) {
  try {
    await BleManager.startNotification(deviceID, ServiceDemo, Characteristic1);
    await BleManager.startNotification(device.id, ServiceDemo, Characteristic2);
    await BleManager.startNotification(device.id, ServiceDemo, Characteristic3);
  } catch (error) {
    warn('Could not start notifications for all characteristics:', error);
    // don't forget to throw the error again to reject the promise
    throw error;
  }
}

If you want to use the then style, you can do this instead.

startNotifications(deviceID) {
  return BleManager.startNotification(deviceID, ServiceDemo, Characteristic1)
    .then(() => BleManager.startNotification(deviceID, ServiceDemo, Characteristic2))
    .then(() => BleManager.startNotification(deviceID, ServiceDemo, Characteristic3))
    .catch(error => {
      warn('Could not start notifications for all characteristics:', error);
      // don't forget to throw the error again to reject the promise
      throw error;
    });
}