Fixing the SwiftUI Animation Bug on macOS Monterey with Xcode 13 Beta 3

Описание: Discover how to resolve the `SwiftUI` animation bug affecting `macOS Monterey` and `Xcode 13 Beta 3`. Follow our detailed guide to ensure your app runs smoothly!
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This video is based on the question https://stackoverflow.com/q/68446619/ asked by the user 'newswiftuser' ( https://stackoverflow.com/u/16324343/ ) and on the answer https://stackoverflow.com/a/68447626/ provided by the user 'workingdog support Ukraine' ( https://stackoverflow.com/u/11969817/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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SwiftUI Animation Bug on macOS Monterey: How to Fix It

If you're developing with SwiftUI on macOS Monterey and Xcode 13 Beta 3, you may have encountered an annoying animation bug. This problem can manifest when using the List view and trying to remove items with an animation applied. Specifically, you might see an error message stating, "Row index 0 out of row range (numberOfRows: 0)" when performing certain actions. In this guide, we'll thoroughly explore this issue and provide a clear solution to help you avoid it.

Understanding the Problem

When using withAnimation to remove items from a list, some developers have reported that attempting to resize the sidebar (or performing similar actions) can lead to erratic behavior and errors in the console. This is particularly true when all items in the list are cleared, leaving it empty.

Symptoms of the Bug

Error message in console: [General] Row index 0 out of row range (numberOfRows: 0) for <SwiftUIListCoreOutlineView: >

Inability to successfully resize the sidebar after clearing the list

The Minimal Reproducible Example

To better illustrate the issue, let's walk through a minimal example that demonstrates how to reproduce the bug:

Create a new SwiftUI macOS application.

Paste the following code into your ContentView:

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

Run the app and attempt to resize the sidebar.

Click the minus button on the toolbar to remove all items.

Observe that resizing the sidebar is now broken, along with console errors.

Solution to the Issue

Fortunately, there is a straightforward fix for this problem. You can modify your code to avoid using withAnimation when calling items.removeAll(). Here’s how you can implement this solution:

Updated Code without Animation

Replace the action in your button from this:

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

To this:

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

Alternative Solution

If you'd like to keep using animations, consider removing the animation from the items.removeAll() method as a last resort until you discover a more permanent solution while the issue is actively being worked on in the SwiftUI framework.

Conclusion

As you've seen, there is a known bug with SwiftUI when using withAnimation to manipulate lists in macOS Monterey while running Xcode 13 Beta 3. By avoiding the use of animations for clearing lists, you can prevent the console errors and unexpected behaviors.

Keep in mind that since Xcode is constantly being updated, staying tuned to the latest releases can reveal fixes for such bugs in the future. Happy coding, and may your SwiftUI apps run smoothly!