Скачать или смотреть Fixing NavigationLink Label, Destination Initialization Issues in SwiftUI

Learn how to effectively use `NavigationLink` in your SwiftUI app to enable navigation with tap gestures while avoiding common pitfalls.
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This video is based on the question https://stackoverflow.com/q/75678396/ asked by the user '권정근' ( https://stackoverflow.com/u/15438259/ ) and on the answer https://stackoverflow.com/a/75678522/ provided by the user 'Jonas Lang' ( https://stackoverflow.com/u/17412749/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Fixing NavigationLink<Label, Destination> Initialization Issues in SwiftUI

When building a todo list app in SwiftUI, you may face an issue regarding the use of NavigationLink, particularly seeing the warning: "Result of 'NavigationLink Label, Destination ' initializer is unused." This problem typically arises when trying to implement multiple tap gestures on a list item for different behaviors. In this post, we’ll explore how to resolve this challenge and ensure that your navigation works seamlessly.

The Problem: Multiple Tap Gestures

In our case, the goal is to create a todo list where:

A double tap on a todo item marks it as completed.

A single tap on the same item should redirect the user to an edit screen (AddView).

Your initial attempt might look like this:

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

This structure raises a warning because NavigationLink is a view and should not be instantiated inside a closure where it isn't being returned or shown directly.

The Solution: Restructure Your NavigationLink

To properly utilize NavigationLink, we should structure it correctly in the list view. Instead of trying to nest it within tap gestures, we make NavigationLink the primary clickable area. Here's how you can modify your ListView:

Step-by-step Implementation

Open the List: Instead of placing the onTapGesture inside the NavigationLink, we want the entire ListRowView to be clickable.

Use a Function for Gesture Handling: Differentiate between single and double taps without nesting the NavigationLink.

Here's a revised version of how to implement this:

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

Explanation of the Code

NavigationLink: The NavigationLink wraps the ListRowView. This means whenever a user taps on the row, they will be taken to the AddView, unless it’s a double tap.

Double Tap Gesture: The .onTapGesture(count: 2) is placed directly on the ListRowView to handle double taps specifically. Using withAnimation ensures that marking the item as completed is visually appealing.

Conclusion

By correctly structuring your NavigationLink and separating the tap gestures, you can efficiently navigate to your AddView while still enabling completion actions on double taps. With these changes, you should no longer see the warning for unused NavigationLink and improve the user experience in your todo list application.

Try It Out!

Implement the provided solution in your SwiftUI app, and see how your dual functionality works seamlessly. Happy coding!