Question

I have a CTCallCenter instance created (alloc/init) after launch. The event handler is never called (neither an NSLog nor a breakpoint fire). If I ask it later about current calls it returns nil. If I call [[[CTCallCenter alloc] init] currentCalls] at the same time then it does return the calls.

As an example while a call is active (I brought the app back to the foreground and a timer later fired) here is a single NSLog showing the long lived CTCallCenter instance, what it returns for currentCalls and what a new transient instance returns:

CTCallCenter(0x1e5639c0): {
    server_connection: 0x1e5640e0   currentCalls: {(
)}  callEventHandler: 0xa0c90
}

(null) 

{(
    CTCall (0x1e5a0fb0) {
    callState: [CTCallStateIncoming]
    Call ID: [1EB2A082-4A12-48C2-A76C-2244F8F402EE]
}

)}

It is apparent there is a handler registered, and that the long lived instance thinks there are no calls. I’m happy to always use a transient instance to get the call list, but I really need the event handler to fire.

Answer 1

I have found the answer. The [[CTCallCenter alloc] init] must be run in the main queue. I was running it in a custom serial dispatch queue. Presumably the CTCallCenter code is doing something with the current queue or perhaps requiring a run loop.

If you do the alloc/init outside of the main queue then it will be correct if immediately called for currentCalls but that data never gets updated nor does the event handler fire. There is no mention of this in the documentation, nor are errors returned or exceptions raised.