I recently created an app that uses CoreBluetooth on iOS to connect to a thermal printer. Everything is going just fine except for one thing. I can see over 20 bluetooth devices but only one is a thermal printer. Is there a way for me to know if this peripheral is a thermal printer or not before connection so that i can display/hide it ? Thanks
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2Check the services it advertise? – Larme Jan 29 '19 at 14:42
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i tried it before, for some reason the list of services is nil – Ali Ysf Jan 29 '19 at 14:49
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2What does it advertise? Could you isolate the advertisement data of the peripheral you are targetting? – Larme Jan 29 '19 at 14:52
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how can i get the list before calling peripheral.discorverServices() since i tried that but did get the response in the delegate function didDiscoverServices – Ali Ysf Jan 29 '19 at 14:55
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You're thinking about this backwards. You don't fetch the list of services and then decide whether to connect. You decide what services you want and scan for those.
When you call scanForPeripherals(withServices:options:), you should almost always pass a list of services you support. If you're passing nil, then you're almost certainly calling it incorrectly unless you're building a general-purpose BLE scanner.
The same is true of discoverServices(_:). You very rarely pass nil there. You pass the list of services you know how to deal with. The .services property is available as a convenience when you know you've already fetched the services, but it's rarely that useful. If you call discoverServices(_:) when it's unnecessary, the system will send you cached data immediately.
Rob Napier
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1that was it, I've been working on connecting and printing properly for the better part of last week. the scanning part was one of my first code inserts thus i totally forgot that i can add arguments to the scan. thanks a lot – Ali Ysf Jan 29 '19 at 15:08