Christian Selig

Small addendum to my previous code question, how do I use an @​Observable as a binding if the object I want to bind is optional? In this case, the object might not be immediately available as it comes in async, but once it comes in, I want it selectable

This code compiles, but the selection is never saved

There's probably a better way to structure this too, in that case I'm all ears!

Gist: https://gist.github.com/christianselig/792257d1270f0c6dd3ebd9fde062ed51

icecreamobserving.swift

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Feb 6, 2024 at 9:25pmIvory for Mac
Show threadBrian WebsterFeb 6, 2024
@christianselig I think what you're looking for is @Bindable https://developer.apple.com/documentation/swiftui/bindable/
Bindable | Apple Developer Documentation

A property wrapper type that supports creating bindings to the mutable properties of observable objects.

Apple Developer Documentation
Show threadsavaranFeb 6, 2024
@bwebster @christianselig this. And I just went through this same confusion. It’s very odd declaring a bindable inside a view body as a flow but solves the problem
Show threadChristian SeligFeb 6, 2024
@bwebster I think I understand Bindable in the context of initializing a new object with the Bindable object, but how would I use it here?
Show threadBrian WebsterFeb 6, 2024
@christianselig I think you should be able to just replace @State with @Bindable in that example? (not 100% sure as I've only used it a couple times myself)
Show threadChristian SeligFeb 6, 2024
@bwebster No dice :(
Show threadZach WaughFeb 6, 2024
@christianselig I think this may be an issue of the type of the .tag being `String` instead of `String?`, which you can fix by doing `.tag(Optional(iceCream))` or casting it to `String?`
Show threadNick Kohrn 🔭 💻Feb 6, 2024
@zachwaugh @christianselig I think this is what I had to do in a project when the picker value was optional.
Show threadChristian SeligFeb 6, 2024
@zachwaugh Aah that worked a charm, thank you!
Show threadMax MelzerFeb 6, 2024
@christianselig Are you aware of „Bindable“? You can also define a Bindable var inside your body callback to access stuff from the environment. https://developer.apple.com/documentation/swiftui/bindable
Bindable | Apple Developer Documentation

A property wrapper type that supports creating bindings to the mutable properties of observable objects.

Apple Developer Documentation
Show threadChristian SeligFeb 6, 2024
@maxmelzer How would I use it in this situation? I've tried a few different incantations to no avail
Show threadMax MelzerFeb 6, 2024
@christianselig Oooh, I think I figured it out. The problem is not about the Observable at all. The trick is that the type of your .tag must be exactly the type of your selection binding, including optionality. Try using „.tag(iceCream as String?)“, that should do the trick.
Show threadVincent FriedrichFeb 7, 2024
@maxmelzer @christianselig 🫠
Show threadMax MelzerFeb 6, 2024
@christianselig Ah, sorry, I see you already got that info. Thanks for the small puzzle, though! :)
Show threadDrew McCormackFeb 6, 2024
@christianselig Can’t you just make it non-optional and use a default instead? (I would go with “chocolate”😁)
Show threadNick LockwoodFeb 7, 2024
@drewmccormack @christianselig you could also just use an empty string/array too right?
Show threadRenaud LienhartFeb 6, 2024
@christianselig FYI the `.tag()` modifier is superfluous here — it provides the same identity as the `ForEach()` already provides
Show threadChristian SeligFeb 6, 2024
@layoutSubviews If I drop it though, it no longer works :(
Show threadRenaud LienhartFeb 6, 2024
@christianselig ah, right, because of the outer `if let`. My bad.
Show threadChristian SeligFeb 6, 2024
@layoutSubviews Oh all good, I'm appreciative that I now understand why it's needed :p
Show threadSteven HuangFeb 6, 2024
@christianselig @layoutSubviews Wait, I don’t understand! Please explain. 😊
Show threadRalph Waldo Pickle ChipsFeb 6, 2024
@christianselig the tag type needs to exactly match the selection binding type—there's no implicit optional promotion
Show threadPakk' Feb 6, 2024
@christianselig I think you need to add @Bindable
Show threadfruitcoder 🍒🍉Feb 6, 2024
@christianselig can you if let the Binding using the unwrap initializer and only the show the Picker?
Show threadDinesh HarjaniFeb 7, 2024
@christianselig say Christian, where can I steal your Xcode color theme from? :D
Show threadChristian SeligFeb 7, 2024
@dinesharjani It's called One Dark! I don't quite remember where I got it from but it looks like a popular one at least
Show threadDinesh HarjaniFeb 8, 2024
@christianselig thanks!
Show threadStijn WillemsFeb 7, 2024
@christianselig feel like UX wise you are missing a loading screen. Present that while the list loads. Then when list is loaded select the first item. No need for optionals then.