I've been searching for a way that if there's any way that an app can push / pull a message to / from another app, assuming that both apps have been installed. I have a feeling that probably that it is not possible, but would like to confirm with SO.
Basically, I'm going to develop two apps, app1 and app2. Let's assume that a user always downloads both of the apps (or, I've found previous discussions over SO that it is possible for an app to figure out if another target app is installed assume it makes Uri registration.) App1 would generate some information and have to pass to app2. One way to do it is that I can have an external server as a relay, and both apps can talk over network. However, is it possible to pass information locally from an app to another app, just like
Service in Android? It would be appreciated if you can give me a keyword or a link. I read it further. Thank you.
Your solution is the
App Groups Entitlement.
NSUserDefaults see: https://developer.apple.com/documentation/foundation/userdefaults#1664611