Dynamic reading of BLE characteristic?

Thanks all for the info. It sounds as if I'm not missing an obvious onRead() at least, which was the thing I was wondering.

on Connect is useful to know. I figured another way (albeit a bit hacky) could be to write to the characteristic from the phone, which triggers the read operation which in turns updates the value with a notify.

As I mentioned I don't actually have a use for this right now - but am learning so just wanted to check the best way of doing this. So thanks for the suggestions - most helpful.