Скачать или смотреть Resolving the ForEach Loop Issue in SwiftUI for Navigation Links

Learn how to correctly handle multiple `NavigationLink`s in SwiftUI by assigning individual states for each item in a `ForEach` loop. Prevent unwanted navigation through your list with this guide.
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This video is based on the question https://stackoverflow.com/q/63012568/ asked by the user 'Kuhlemann' ( https://stackoverflow.com/u/12637422/ ) and on the answer https://stackoverflow.com/a/63012828/ provided by the user 'Asperi' ( https://stackoverflow.com/u/12299030/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Resolving the ForEach Loop Issue in SwiftUI for Navigation Links

When developing a SwiftUI application, you may encounter an issue where tapping on a contact in a list triggers the navigation for all items instead of just the selected one. This common problem happens due to the way state is managed in ForEach loops, particularly when used with NavigationLink. This guide will guide you through understanding the issue and provide a clear, organized solution.

Understanding the Problem

In your SwiftUI application, you have a ContactsView that displays a list of contacts using ForEach. You want to navigate to a detail view for the selected contact. Here’s the primary code causing the issue:

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The line isActive: self.$userViewModel.showContacts binds all NavigationLinks to a single state (one-to-many). This means that when the state changes (for example, when you tap on one of the contacts), it inadvertently activates every NavigationLink in the list, resulting in all detail views being presented in succession.

The Solution: Using Individual States

To ensure that tapping a contact opens the correct details view without triggering others, you need to implement a solution that assigns an individual state to each contact. You can do this using a @ State variable that tracks the currently selected contact by its ID.

Step-by-Step Implementation

Declare a Selected Contact ID State: Start by adding a @ State variable to your ContactsView. This will hold the ID of the selected contact.

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Modify the NavigationLink: Update your ForEach loop by removing the isActive binding and using the tag and selection properties instead. Each NavigationLink will now reference the contact.id as its tag.

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Set the Selected Contact ID: Finally, when a user taps on a contact, you’ll set the selectedContact state to the tapped contact’s ID. This allows SwiftUI to activate the corresponding NavigationLink while keeping others inactive.

Complete Code Example

Here’s how your ContactsView might look after implementing the changes:

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Conclusion

By following these steps, you can resolve the unwanted behavior of multiple NavigationLinks activating simultaneously in SwiftUI. By using a single state variable that tracks the selected contact's ID, you ensure that only the intended view is displayed when a contact is tapped. This approach not only improves the user experience but also adheres to best practices in state management within SwiftUI applications.

Feel free to implement this solution in your app and enjoy a smoother navigation experience!