Скачать или смотреть How to Re-render Your Parent View After a Popup in SwiftUI

Discover how to effectively re-render your main view when changes are made in a popup settings view in SwiftUI using @ AppStorage.
---
This video is based on the question https://stackoverflow.com/q/77955517/ asked by the user 'Dany Jamous' ( https://stackoverflow.com/u/21073430/ ) and on the answer https://stackoverflow.com/a/77955625/ provided by the user 'Anshul' ( https://stackoverflow.com/u/3376425/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Render parent view again after pop up SwiftUI

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
How to Re-render Your Parent View After a Popup in SwiftUI

SwiftUI has brought a new paradigm to building user interfaces in iOS and macOS applications. However, some developers face challenges when trying to re-render parent views after a popup settings view has been modified. If you’ve ever wondered how to update your main view when values change in a settings popup, you’re in the right place.

In this guide, we’ll delve into exactly how changing a property in @ AppStorage impacts the re-rendering behavior of your SwiftUI views, and we'll provide an effective solution to ensure your main view updates properly.

Understanding the Problem

You have a main view and a settings view that share a property stored in @ AppStorage. When you make changes in your settings view, the concern is whether the main view will automatically re-render, and more specifically, if the onAppear method will be triggered again upon dismissing the settings view.

Key Points to Note:

Main View: Displays values computed using properties from @ AppStorage.

Settings View: A popup that allows you to change those properties.

Re-rendering Concern: Will the main view update and will onAppear be executed again?

The Solution

Automatic Updates with @ AppStorage

The great news is that if your main view relies on a property stored in @ AppStorage, it will update automatically when that property changes. Here’s how:

Automatic Observation:

@ AppStorage is a property wrapper that observes changes in UserDefaults.

Whenever you modify the @ AppStorage value from your settings view, SwiftUI triggers a re-render of any view that references that value.

Why onAppear Won't Trigger Again

While the main view updates because of the @ AppStorage change, it’s crucial to understand that the onAppear method will not be called again. This is because the main view remains in the view hierarchy (i.e., it hasn't been removed and re-added).

Alternative Approaches

To effectively manage behavior after you dismiss your settings view, consider these alternatives:

Custom Publisher: Instead of solely relying on onAppear, you can create a custom publisher that listens for changes in your settings view and notifies your main view to update accordingly.

Observable Object: Use an ObservableObject that your settings view modifies and that the main view observes. This can provide a more robust solution for managing state across your views.

Implementation Tips

Setup @ AppStorage: Ensure you have your property defined with @ AppStorage in your main view.

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

Using ZStack for Views:

You can leverage the ZStack to display your settings view on top of the main view.

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

Using ObservableObject:

Create an observable model that can be shared between your main and settings views for easier state management.

Conclusion

By understanding how @ AppStorage works and implementing the suggested alternatives, you can effectively manage re-rendering your main view after changes made in a popup settings view. Remember to consider using an ObservableObject or a custom publisher for more control over your view updates.

If you have further questions or need help with specific implementations, feel free to reach out! Happy coding in SwiftUI!