Switching from CallKit UI to in-app UI

4
votes

I have a VoIP app. It used to work without CallKit, so it has its own in-app call UI. I'm now integrating CallKit UI to handle calls which happen when the app is not running, and have a question:

What is the recommended way to detect a moment when the CallKit UI is dismissed and is going to switch to the in-app UI?

Currently I see that the CallKit UI disappears in 2 cases:

  1. when the app process is not running, and the device is unlocked (e.g. on the home screen) and the call arrives, the CallKit UI appears at first, but if you accept the call (answer), then the CallKit UI disappears immediately, and the app appears.
  2. when the app process is not running, and the device is locked, the call arrives, the CallKit UI appears, you accept the call (answer), and then press the app icon in the CallKit UI, then again the CallKit UI disappears, and the app appears.

What is the recommended way to detect these conditions in order to spawn the in-app UI?

The reason why I don't want to have the in-app UI started all the time is performance and logic. I think it would be wasteful to show and update the controls and video views (the app has video support) while the CallKit UI is on top of the screen. It would be more logical to me if I could detect that the UI switch is needed, and create a UI at that point.

I have looked over the CallKit API, but found nothing for that purpose.

2
ioscallkit

2 Answers

3
votes

For the second use case, I have logic in AppDelegate like this:

func applicationWillEnterForeground(_ application: UIApplication) {
    maybeShowCallUi()
}

fileprivate func maybeShowCallUi() {
    if CallManager.shared.calls.count > 0 {
        print("One or more calls active.")
        DispatchQueue.main.async() { [weak self] in
            print("Trying to show in call UI.")
            self?.showInCallViewController()
        }
    } else {
        print("No calls active.")            
    }
}

My CallManager object is similar to the SpeakerBox sample code that Apple provided. It keeps track of all calls.

1
votes

After the user Answers the call, app call screen should be visible. For that, inside the following method write your code to make app call screen visible. 

    - (void)provider:(CXProvider *)provider performAnswerCallAction:(nonnull CXAnswerCallAction *)action {
        //show call screen here. 
      }