//Header File
<CallKit/CXCallObserver.h>
CXCallObserver *callObserver = [[CXCallObserver alloc] init];
// If queue is nil, then callbacks will be performed on main queue
[callObserver setDelegate:self queue:nil];
// Don't forget to store reference to callObserver, to prevent it from being released
self.callObserver = callObserver;
// get call status
- (void)callObserver:(CXCallObserver *)callObserver callChanged:(CXCall *)call {
if (call.hasConnected) {
// perform necessary actions
}
}