@16:19 According to the Swift Proposal, "A global actor type can be a struct, enum, actor, or final class. It is essentially just a marker type that provides access to the actual shared actor instance via shared".
This has been a great series of videos as I have gotten used to enjoying from you. Having built several large apps there are certain things that are great candidates for global actors. In fact, most of the current singletons I use are to access a server somewhere and share the data throughout the app. Thanks for boiling this down to the essentials and presenting it so well.
Awesome content Nick! Regarding your question of whether to use a final class or structure for your singleton [16:50]? According to Stackoverflow answer 36788169 , classes are preferred to structures when working with singletons. One of the posts illustrates this with an example.
Paused at 17:50. For one time use actor MyNewDataManager I recommend putting it and MyFirstGlobalActor in the file and marking MyNewDataManager as fileprivate. That should keep it from being accidentally used.
This video explains well how the MainActor functionality is just built on top of the globalActor API, but with this simplistic example I've still no clue in which scenario I should create my own globalActor. Does anyone know a video or article with an more realistic example that clearly shows what problem this can solve?
Great series, very well explained. A question is have @10:50, globalactor must be singleton. @12:07, we are using a struct as globalactor and makes it singleton. I wonder why we use a struct (value type and not a reference type) as a singleton? Doesn't singleton negate the purpose of value type that can copy its value and make a new instance?
Since globalActors are by definition a single instance this leads me to believe they should be structs for access time reasons. Profile several use case or your particular use case may be the best answer here because there is a certain amount of optimizations going on internally. There was a WWDC video about this.
@@hashcat5721 I’ll what can find. My next few days are busy and since WWDC isnt fresh in my mind now its going to taking a bit of digging. In the mean time you may wantbto google WWDC GlobalActors, there cant be much out there on this.
16:50 What about using there`@globalActor actor MyNewDataManager { }` where init is private and all logic is in this actor? Isn't that a better solution?
I love your videos so much and there very useful. There is so little good tutorials on TH-cam, is there anyway you could make a video or two on implementing the camera in SwiftUI as a full screen.
This made a lot of sense, right until the point where I switched to Swift 6, now I’m struggling to understand all the weird errors that pops up. Understanding and working with GCD and all its weird quirks is much less complicated than swift concurrency at this point.
It is not running on the main thread. It's a mistake from the author. The viewModel.getData() method is awaited on a background thread. If the function, or the whole class was explicitly marked with @MainActor, then yeah, that would be running on the main thread and also blocking the UI.
In that case you would simply design a different class. There's a reason to use singletons (and reasons not to). It's YOUR job as a programmer to know how to apply the tools.
I'm becoming an intermediate Swift developer having followed your courses since January and written some fairly heavy apps. Now I'm starting to get my code Swift 6 ready, and learning more about actors, I'm wondering if, in the MVVM model, should all ViewModel classes be tagged at @MainActor?
Is there any reason why you can not/should not add @globalActor on MyNewDataManager and make it a singleton to avoid risking the issue you called out with multiple instances of it?
is @MainActor private lazy var mapView: MKMapView = { let mapView = MKMapView() mapView.translatesAutoresizingMaskIntoConstraints = false mapView.delegate = self mapView.showsCompass = false mapView.showsUserLocation = true return mapView }() this a valid usage? because it don't give any errors but also if I mark this with await, xcode warns me that no async process occurs
@16:19 According to the Swift Proposal, "A global actor type can be a struct, enum, actor, or final class. It is essentially just a marker type that provides access to the actual shared actor instance via shared".
This has been a great series of videos as I have gotten used to enjoying from you. Having built several large apps there are certain things that are great candidates for global actors. In fact, most of the current singletons I use are to access a server somewhere and share the data throughout the app. Thanks for boiling this down to the essentials and presenting it so well.
Dude, thanks a lot for making these videos. The quality and curation of content are spot on.
You're welcome! Thanks for the comment.
Every time I come to these videos I learn and understand more. Thank you so much Nick for these highly reliable videos.
Awesome content Nick! Regarding your question of whether to use a final class or structure for your singleton [16:50]? According to Stackoverflow answer 36788169 , classes are preferred to structures when working with singletons. One of the posts illustrates this with an example.
Paused at 17:50. For one time use actor MyNewDataManager I recommend putting it and MyFirstGlobalActor in the file and marking MyNewDataManager as fileprivate. That should keep it from being accidentally used.
thank you so much for this whole playlist i was having a hard time understanding stuff but these are so well explained that i understand it now
Another excellent video. Can't wait to watch the last 2 videos
This video explains well how the MainActor functionality is just built on top of the globalActor API, but with this simplistic example I've still no clue in which scenario I should create my own globalActor. Does anyone know a video or article with an more realistic example that clearly shows what problem this can solve?
Great series, very well explained. A question is have @10:50, globalactor must be singleton. @12:07, we are using a struct as globalactor and makes it singleton. I wonder why we use a struct (value type and not a reference type) as a singleton? Doesn't singleton negate the purpose of value type that can copy its value and make a new instance?
Thanks, Nick, for creating outstanding content.
Thanks, this video is perfect to better understand the use of MainActor
Since globalActors are by definition a single instance this leads me to believe they should be structs for access time reasons. Profile several use case or your particular use case may be the best answer here because there is a certain amount of optimizations going on internally. There was a WWDC video about this.
Can you give me a link to this point at WWDC ?
@@hashcat5721 I’ll what can find. My next few days are busy and since WWDC isnt fresh in my mind now its going to taking a bit of digging. In the mean time you may wantbto google WWDC GlobalActors, there cant be much out there on this.
16:50 What about using there`@globalActor actor MyNewDataManager { }` where init is private and all logic is in this actor? Isn't that a better solution?
Thank you for these amazing series. Really helps me as a Junior iOS developer
Do jr need this for entry level ?
@@natgenesis5038 none of the interviews asked me about global actors. But not bad to know I guess
I love your videos so much and there very useful. There is so little good tutorials on TH-cam, is there anyway you could make a video or two on implementing the camera in SwiftUI as a full screen.
A global actor can be a struct, enum, actor, or final class. (Source: SE-0316)
awsome as always
Is there a disadvantage of putting mainactor on published?
This made a lot of sense, right until the point where I switched to Swift 6, now I’m struggling to understand all the weird errors that pops up.
Understanding and working with GCD and all its weird quirks is much less complicated than swift concurrency at this point.
It needs to get way more Thumbs up.
Friends, 11K views and only 461 likes. More we give likes, more users will see such videos.
7:54 this is incredibly confusing, why is it running on the main thread, it is async? And are you treating main actor = main thread?
It is not running on the main thread. It's a mistake from the author. The viewModel.getData() method is awaited on a background thread. If the function, or the whole class was explicitly marked with @MainActor, then yeah, that would be running on the main thread and also blocking the UI.
Now I know how to use nonIsolated and Global Actors but I still don’t understand their use cases. 😢
Single Instance? Whats If I want to have separate instances per Account in a multi account app? Horrible api
Can you explain further? What specifically is a horrible api? What would you propose as an alternative?
In that case you would simply design a different class.
There's a reason to use singletons (and reasons not to).
It's YOUR job as a programmer to know how to apply the tools.
First
Good Boy 👏🏼
I'm becoming an intermediate Swift developer having followed your courses since January and written some fairly heavy apps. Now I'm starting to get my code Swift 6 ready, and learning more about actors, I'm wondering if, in the MVVM model, should all ViewModel classes be tagged at @MainActor?
Yes, I would
Is there any reason why you can not/should not add @globalActor on MyNewDataManager and make it a singleton to avoid risking the issue you called out with multiple instances of it?
is @MainActor private lazy var mapView: MKMapView = {
let mapView = MKMapView()
mapView.translatesAutoresizingMaskIntoConstraints = false
mapView.delegate = self
mapView.showsCompass = false
mapView.showsUserLocation = true
return mapView
}()
this a valid usage? because it don't give any errors but also if I mark this with await, xcode warns me that no async process occurs
Why nick doesn’t like to use singleton he didn’t give a reason why. Can somebody tell me ?
Explained here: th-cam.com/video/E3x07blYvdE/w-d-xo.html
"The @MainActor attribute should be placed before the @Published property wrapper. " -ChatGPT-