Core Bluetooth Restoration Timing Issue

Question

I thought I had the whole bluetooth restoration thing working (acting as a central), then I tried the following:

1 - Peripheral sends single bluetooth packet every 1 second
2 - At random time, I kill app (either using the debugger stop, or another app to eat all the memory)
3 - Check if restoration took place

This worked about 80% of the time and the errors were seemingly random.

After two days I was able to reliably reproduce the problem:

1 - Peripheral sends two packets 1000 ms apart
2 - Kill the app programatically (kill(getpid(),SIGKILL) some delta after the first packet (100ms,200ms...) which is some delta before the next packet (900ms, 800ms)
|--PKT-------850ms------KILL--150ms--PKT--|
3 - Second packet arrives and wakes the app up

What I found is that if the time between app termination and the next packet arriving is greater than about 150ms, restoration takes place as it should 100% of the time.

If the time between app termination and the next packet arriving is less than about 150ms, if I open the app manually within 10 seconds, restoration takes place 100% of the time. If I open the app manually after more than 10 seconds, it's as though no restoration took place. Also, once the app is killed, I watch the bluetooth symbol in the status bar and after exactly 10 seconds the connection is dropped.

Testing took place on an iPhone 4s running 8.1 and then 8.2.

This seems like a bug... I can provide my code if that helps however I've stripped it back to the bare minimum delegate implementations. I've tried putting the central manager on a different queue to no avail. This is real issue for my product as it relies upon session-based, background bluetooth tracking. Any thoughts?

Answer 1

这似乎可以在iOS 9+中解决