Learn everything you need to know about SwiftUI's new Bindable property wrapper. I will show you the problem that it solves, and why it doesn't replace @Binding by any means.
Thank you very much. I've watched a number of videos introducing @Bindable, but none have been so clear to explain its purpose (with such a simple example) as yours.
When I just thought that video could not be any better, you brought the issue with @Environment after 11 minutes on the table: AWESOME! Thank you so much for this video. I spent a whole day and night with that nightmare error message "can't find controller in the scope", which was exactly the situation that you describe here (in my case 'controller' is kind of a viewmodel). So, this video came to rescue me, although I found it very late. Thanks again !!! 🤩
Great content, keep going! The only thing - PLEASE remove the background music. That extra noise really makes it hard to listen to you, especially annoying if you watch at 1.5-2x speed (which I often do). Check how the Fireship channel does the narration without almost anything but his voice, and that's great. Thanks and good luck!
I second this comment as well. BG music is super distracting. That said, awesome video and keep them coming. Thanks for doing this. Please lower or remove background music on future videos
Thanks! I've uploaded a new video with the bg music far lower, it's the most recent one on the channel so feel free to take a look. The reason I've included it is because to me narration with complete silence is rather boring and lots of channels I watch do have very mild music playing in the background. I might end up removing it in future videos but I want to give it a few tries to see if there's a sweet spot.
Thanks! i do like to have some sound in the background instead of pure silence so in my latest video I brought the volume down by a lot. It's an ongoing experiment for the moment
Nice video, that I will come back to every time I mess up this. How can you use this without importing Observation? (Or SwiftData which also includes observation)
I'll probably do a re-record of this video at some point without the bg music. It's a shame that it's not possible to "update" a video without a full reupload
No, an environment object is an object that conforms to ObservableObject and lives in the environment. An @Bindable property allows you to bind to properties of an Observable instance because without it yu can't bind at all. The environment and @Bindable both solve very different problems so you can't replace one with the other
Probably because reference semantics are needed to ensure that you can actually observe a specific instance instead of having multiple separate copies that would get out of sync.
@State is no longer required with @Observable macro on your model/view model 🎉. Since the model is now observed, watching for changes, it will efficiently update the views the are using any property outputting change
That's true for the observation part. But if you want the observable model's state to correctly be persisted you need @State to prevent SwiftUI from making a new instance every time your view struct is initialized. Note that this is only the case if you _own_ the observable in the view. Views that receive the instance in their init can indeed use a plain let/var
10:33 One question, at line 11, you have @State on a class, should that not be @StateObject instead? And if not, if that's all done. Is there any longer a need for @StateObject?
If I understood it correctly from another source, it seems like before there was a memory leak with using @state with a class but now with iOS 17 that has been fixed and it's now recommended to use @state instead. However I'm not 100% sure so please double check yourself as well :)
@StateObject should be used for instances of ObservableObjects that you create in the view. So if a view creates an ObservableObject instance that you want to observe, you use @StateObject. When you're using the new @Observable macro, the SwiftUI view will observe your object no matter what. You use @State in order to make sure that the Observable instance you create persists when SwiftUI makes new instances of your view in response to model changes. Without @State you'd end up with fresh instances of your Observable every time a new view struct instance is created (which can be quite often)