iphone - Is there inter-app communication when apps start in iOS? -

I'm relatively new to iOS app development and I'm just trying to find out some things that me, more Are the essence When do other applications start, how do apps know? The closest example I can imagine is what I am trying to ask, when the music is playing in the background and you open another app that has the sound and the music stops whether it takes a new app authority or what the difference app Is communication? How does communication work if communication happens? Like it is a message that can reach or what?

Sorry if he does not mean much, then I tried to expand what I could have done. I did not find anything on this on Apple's developer website thank you in advanced!

There is no inter-app communication, each app is living in its own world, and as far as Your app is concerned, this is the only app on the phone. The way communication goes, it is that an app talks to the system, and the system speaks to your app. The way the system sends a message to your app, it usually happens in the representative of the structure you are working on. In your example, opening your app to play the audio will send a message to the system, and the system will tell other apps to stop playback of audio. That other app does not know that this was your app that started the stop. Another example is the app representative will send your app message such as application: didFinishLaunchingWithOptions: , which in this method lets you initialize the app's custom or applicationWillResignActive: which is usually sent The user clicks the Home button or receives a phone call, so here you can save your game etc.

In fact, the iOS system is very complex, very complex so that in detail can be explained, I suggest reading excessively, some of it may be a little dry, but they are consistent with their initial initial methods. You can.