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yanshouwang / bluetooth_low_energy

A Flutter plugin for controlling the bluetooth low energy.
https://pub.dev/packages/bluetooth_low_energy
MIT License
50 stars 16 forks source link

Discovery mode misses some devices and shows duplicates on Linux #32

Closed acfsmith closed 10 months ago

acfsmith commented 11 months ago

I tried example on Linux. After I commented PeripheralManager I got this picture:

deviced-found

Some devices listed few times, others missing. Here is screenshot that shows actual devices discovered by OS at the same time:

real-devices

yanshouwang commented 11 months ago

Thanks for your report!

The repeated devices seems like a bug, it will be fixed in the next release.

The missing devices I guess maybe system cache, can you make sure that the missing devices were still advertising at that time?

acfsmith commented 11 months ago

Yes, I can guarantee that at least one of them (Tacx NEO) was actively advertising at that moment. I also tested it from MacOS and it appeared in the list as expected.

yanshouwang commented 11 months ago

Yes, I can guarantee that at least one of them (Tacx NEO) was actively advertising at that moment. I also tested it from MacOS and it appeared in the list as expected.

I just rememberd that I occured this issue before, seems the bluz.dart package can only discover peripherals which advertisement contains flag field with a General Discoverable Mode bit mask.

I dont' konw how to make the bluez package can discover devices without this flag for now, and the bluz.dart package has not updated for a long time, issues even not be answered there, no ideas how to resolve this for now.

I think the only way to make the device to be discovered is add the flag value to the device's advertisement.

Update:

I found an error in the codes when resolve the advertisement, after fixed that error I believe the missing devices can be discovered.

Can you clone this project and change to the 5.0.0 branch, then run the example in the bluetooth_low_energy_linux folder to see if the issues above are fixed?

acfsmith commented 11 months ago

I tested the 5.0.0 branch. Scanning works fine for me now. Thanks a lot!

yanshouwang commented 11 months ago

I tested the 5.0.0 branch. Scanning works fine for me now. Thanks a lot!

Glad to hear that, there are still some work(Android and iOS) to do before the 5.0.0 release, I will make a pre realease version once I finished that.

yanshouwang commented 11 months ago

The 5.0.0-dev.2 has pre released and should have fixed this issue.

acfsmith commented 11 months ago

Now it can easily detect devices in Linux. But the discovery callback behaviour has changed. Before this release, it called discovery callback for every discovered device after every advertisement. Now it calls discovery callback very rarely, so the signal strength isn't updated. Also, because of this, I can't tell when the device has finished advertising.

yanshouwang commented 11 months ago

Now it can easily detect devices in Linux. But the discovery callback behaviour has changed. Before this release, it called discovery callback for every discovered device after every advertisement. Now it calls discovery callback very rarely, so the signal strength isn't updated. Also, because of this, I can't tell when the device has finished advertising.

It's weird but I didn't change the discover logic at all, I tested and I can reproduce this, the RSSI didn't changed after added, but when I opened the system's bluetooth setting pannel, the RSSI will change for some time, after a few moment later the RSSI didn't change again until I reopened the bluetooth setting again...

Curious if this normal in the previous version?

EDIT

I noticed that the RSSI is updated but very slow, you can test it in the 5.0.0-dev.3 version, I added some useful info for debug.