BLE failing to connect after period when iPhone on charge

. I have an App that has been working reliably on older iPhones but fails on newer devices running iOS 12.


The App links to a device using BLE. The device priodically connects, exchanges data then disconnects, In the didDisconnectPeripheral method I tidy up then attempt to reconnect using connectPeripheral. Several minutes later, when the device advertises on BLE the magic of iOS automatically wakes up the App an re-establishes the connection. This has worked relaibly for years but recently users have reported that the connection dies and this MAY be after a period when the phone is on charge.


My guess is that the connectPeripheral request has been lost by iOS and so I never get the callback.


Does anyone have any ideas?

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larishi401
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The problem still persists in 12.0.1. After further analysis it appears that the BLE connection fails at around 03:00 (UK time) only when the charger is connected, irrespective of when the charger was connected. How weird is that?

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larishi401
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It is possible that your app is being terminated during some periodic maintenance cycle.


Do you have Bluetooth State Preservation/Restoration implemented in your app? That should restore your app state after such an event.


Bluetooth State Restoration is an opt-in feature explained more in detail here: https://developer.apple.com/library/archive/documentation/NetworkingInternetWeb/Conceptual/CoreBluetooth_concepts/CoreBluetoothBackgroundProcessingForIOSApps/PerformingTasksWhileYourAppIsInTheBackground.html#//apple_ref/doc/uid/TP40013257-CH7-SW5

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Gualtier Malde
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Thanks Gualtier


I will give this a go. Problem is it takes several days of testing to check. I will reply with the outcome


Bill


UPDATE:


Its been an interesting journey but I'm pleased to say the problem has gone away but I'm not sure why. My old development machine expired so I had to buy a new MacBook. After updating to the latest iOS I could get the latest XCode. This threw up a few build problems which I fixed. I also spotted that the entry in my .plist for Always On Location which I sorted.I already had the Bluetooth State Restoration enabled as suggested by Gualtier.

Anyway has been working for 2 days now so I think the problem has gone away.

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larishi401
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