I'm programming in iOS not so long. I was mainly programming UI related stuff like animations, custom UIControls etc.
I need in my new app to: Display loading activity indicator and in the same time:
- load some remote data from server parse them and store in local core data
- load some data from local core data
- get user position from location service
After this I have all data needed to display next view controller and dismiss loading indicator.
Question is how can I do this all? I need to support iOS9, iOS10, 11, 12. I understand that this needs to be done in background threads and then I need to merge all data from each task and switch to next view controller. I can't use any external libraries like rx-swift or promise-kit. Maybe there is any experienced iOS developer who can give me some main guidelines how to approach to this kind of application flows? I can imagine there is a lot of ways I can do it some of them are better and some of them are worse. Any guidelines would be very helpful for me. Thanks.