Скачать или смотреть How to Properly Wrap UIScrollView in SwiftUI and Update Published Properties

Discover how to effectively wrap a `UIScrollView` in SwiftUI, ensuring that your `Published` properties are updated correctly in your SwiftUI view.
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This video is based on the question https://stackoverflow.com/q/69250501/ asked by the user 'FE_Tech' ( https://stackoverflow.com/u/8409258/ ) and on the answer https://stackoverflow.com/a/69253772/ provided by the user 'Phil Dukhov' ( https://stackoverflow.com/u/3585796/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Properly Wrap UIScrollView in SwiftUI and Update Published Properties

When working with SwiftUI, you may encounter scenarios where you need to incorporate UIKit elements like UIScrollView to enhance your app's functionality. A common challenge is ensuring that SwiftUI detects changes in your Published properties when wrapping a UIScrollView. In this guide, we'll explore a practical solution to achieve this seamless integration.

The Problem

You might be trying to access the contentOffset property of a UIScrollView and bind it to a SwiftUI property using @ Published or @ Binding. However, SwiftUI may not respond to these property changes as expected. This can lead to unpredictable behaviour where the UI does not reflect the current state of your view model.

In the following sections, we will discuss the solution to this problem through a structured example.

Understanding the Current Structure

Let's break down the original implementation. You have a MyScrollView struct that conforms to UIViewRepresentable, allowing you to bring UIKit components into SwiftUI. Here's a simplified version of your current setup:

UIScrollView Implementation

[[See Video to Reveal this Text or Code Snippet]]

ContentView Example

Your ContentView implementation can be seen below:

[[See Video to Reveal this Text or Code Snippet]]

The Solution

The main issue in the original implementation is that the content closure isn't being refreshed when the view updates. To ensure that your content reflects state changes, we need to modify how we handle content in the updateUIView method.

Steps to Achieve Functionality

Store the Hosting Controller: Inside the Coordinator, store an instance of UIHostingController.

Update the UIView: In updateUIView, set the updated rootView for the hostingController.

Here’s how your MyScrollView should look after these modifications:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By following the outlined steps, you can successfully bind your UIScrollView content offset to your view model's Published properties, making the SwiftUI view responsive to changes. This approach enhances the interactivity of your SwiftUI apps while utilizing the power of UIKit components effectively.

Now you have a robust solution that can handle additional functionalities while keeping your SwiftUI app reactive and user-friendly.

With this guide, you should be able to successfully integrate UIScrollView into your SwiftUI app without missing a beat!