How to follow swift events?

Question

iOS

Good morning.
I’m studying swift to the fullest and I don’t understand how to follow the events here.
Let's say I found a bunch of manuals on how to connect an apple, google map, but I didn’t find in any of them how, let’s say, to keep track of what was scrolling and the map changed the center or zoom.
The same story with AVFoundation, I wanted to make a music player, but did not understand how to make a duration slider. Those. show where the song is playing. Brains were only enough to set the timer and determine the current position.
I think there is a good solution for all this? Can I link to the norms of the article or documentation on this all?
Maybe someone has links to open source products: work with maps and the player? Only the final ones, and not for example, where there are a couple of buttons and they turn the music on / off. And if you switch to another controller, then everything breaks.
Also, a bunch of small questions pop up all the time, is there any chat, swift group, where there are more than one / two random guests? =)
thanks in advance

Answer 1

У всего есть delegate и именно методы delegate дергаются при каких-либо событиях.
По Mapkit за 5 секунд гуглится вот это stackoverflow.com/questions/5556977/determine-if-m...

- (void)mapView:(MKMapView *)mapView regionWillChangeAnimated:(BOOL)animated
- (void)mapView:(MKMapView *)mapView regionDidChangeAnimated:(BOOL)animated

Для AVFoundation тоже есть delegate.
Посмотреть какие методы есть у того или иного delegate можно нажав на него с зажатой клавишей Command.