It's not possible to retrieve list of paired peripherals from iOS. Neither it's possible to check if specific peripheral is paired.
Retrieving peripheral which is paired
There are two cases which you need to consider:
Peripheral may be already connected in the system (iOS connects automatically with some peripherals in order to for example display battery level). In this case peripheral won't be broadcasting and detection using scanForPeripherals
won't work.
Peripheral is paired, but disconnected. In this case retrieveConnectedPeripherals(withServices:)
won't work.
Therefore to retrieve your peripheral you need to combine both things. First you need to check if it's in peripherals returned from retrieveConnectedPeripherals(withServices:)
. If not you should scanForPeripherals
.
If you want to retrieve peripheral which is out of range, you can try to use retrievePeripherals(withIdentifiers:)
, however it may return also not paired devices and it relies on peripheral's UUID
which you have to save after pairing.
Detecting if peripheral is paired
There is one way to detect if the specific peripheral is paired. You need to try to read from protected characteristic (which requires encryption - bonding). If you receive expected data, it means that user accepted pairing request. Otherwise you will receive empty response or none.
References
You can read more about Bluetooth in my articles:
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