SwiftUI community shim version?

masters3d · July 18, 2021, 7:10am

hi,

Is anybody aware of any serious efforts to provide some sort of shim package that can bring features only available in newer releases back to the original 2019 version?

For example in SwiftUI (2020), LazyVGrid and LazyHGrid were introduced but these could be back deployed if somebody were to put a shim SwiftUI package that provided this functionality as long as we are not using new language features. For example, something like this article Backward Compatibility with SwiftUI - The SwiftUI Lab

I hear folks say that many times what stops them from using SwiftUI is that the need to support current plus two previous iOS version so this year seems to be an option for adoption for some folks.

Thanks!

DevAndArtist · July 18, 2021, 7:28am

Here is my version of a custom StateObject that works on iOS 13. It does however require one extra cycle per view lifecycle but that's a tiny price to pay, other than that it works and behaves the same and provides the same API surface:

gist.github.com

https://gist.github.com/DevAndArtist/231e9cc03b58c2c1c49c3496b5820fbd

CustomStateObject.swift

import SwiftUI
import Combine

/// The idea is to use State to create a storage object which will be
/// cached and restored by the framework. Then during the update phase we
/// re-inject the object into a nested ObservableObject and subscribe to the
/// ObjectType’s objectWillChange to forward to the _MessageForwarder’s
/// objectWillChange which is already subscribed by the framework as it’s an
/// inner dynamic property of our custom PW which is also a dynamic property.
@propertyWrapper

This file has been truncated. show original

Peter-Schorn · July 18, 2021, 7:44am

This article does not bring features only available in newer releases back to the original 2019 version. All it does is provide wrappers that use the new APIs when they are available or fall back on the older APIs. This is completely different from what the rest of your comment is about.

Given that SwiftUI is closed source, backwards-compatible implementations are going to be few and far between.