Скачать или смотреть How to Properly Display API Data in SwiftUI

Learn how to effectively display string data from an API call in SwiftUI. Avoid common pitfalls and ensure your views update as expected using the ObservableObject pattern.
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This video is based on the question https://stackoverflow.com/q/72681398/ asked by the user '3sr0 store' ( https://stackoverflow.com/u/19271131/ ) and on the answer https://stackoverflow.com/a/72682537/ provided by the user 'vadian' ( https://stackoverflow.com/u/5044042/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Properly Display API Data in SwiftUI: A Step-by-Step Guide

When building applications with SwiftUI, one common issue developers face is displaying data fetched from an API. Have you ever encountered a situation where you successfully retrieved data from an API but couldn't display it in your SwiftUI view? If so, you're not alone! In this post, we will discuss a specific example, the problem related to displaying the string data from an API, and how to effectively solve it.

The Problem

In our case, a developer tried to fetch API data using an ObservableObject class and then access that data in a SwiftUI view. The process seemed to be working correctly; however, the string values were not showing up in the view. The developer's code included the following structure:

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

Why It Didn't Work

The main problem in this code is that the developer is creating a new instance of the Api class inside the onAppear closure. Thus, the getDataModelApi method is called on this new instance, and the original model3 instance remains unaffected. As a result, the title string doesn't update and the view remains empty.

The Solution

To solve this issue, we need to reference the existing instance of Api (model3) that is already in use by the view. Here is the step-by-step fix:

Step 1: Update the onAppear Closure

Instead of creating a new instance of the Api class, you should call the getDataModelApi() method on the model3 instance that is already tied to your view. Here’s the updated code for the ContentView:

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

Step 2: Testing the Solution

After updating this code, make sure to run your app again. Observe that the Text component named model3.title will now correctly display the string value fetched from your API when the view appears.

Additional Best Practices

While this solution resolves the immediate display problem, here are a few best practices to keep in mind when working with APIs in SwiftUI:

Error Handling: Always implement error handling for your API calls to manage any potential issues gracefully.

Loading States: Consider adding loading indicators to inform users when data is being fetched.

Data Updates: Take advantage of @ Published properties to automatically update the views when data changes.

Conclusion

Fetching data from an API and displaying it in SwiftUI can be a delightful process, but it comes with its challenges. By ensuring you reference the correct instances of your ObservableObject, you can effectively manage and display your data. If you run into issues, remember to check how you're passing data around and if your API calls are being executed on the correct instance.

Implement the solution discussed above, and you’ll have a functioning SwiftUI view that displays string data from an API without any hiccups! Happy coding!