How to Efficiently Fetch User Names in a SwiftUI Nested API Call

Explore how to handle nested API calls in SwiftUI and retrieve user names effectively within your questions interface.
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SwiftUI Nested API JSON Call: Fetching User Names Dynamically

When developing a SwiftUI project that requires retrieving data from an API, you may run into challenges with nested API calls. One common scenario involves displaying a list of questions, where each question has a senderId that must be used to fetch additional user information. This can be tricky, especially when you're constrained by the structure of an existing API. In this guide, we'll explore how to efficiently handle such a situation in SwiftUI.

The Problem

In your project, you are using QuestionApiCall().getAllQuestions to obtain a list of Question objects. Each Question object contains essential data like the content of the question and a senderId, which you need to use to fetch the corresponding user name through UserByApiCall(id: senderId).getUserById. The main challenge is calling the user API for each question while ensuring smooth loading and rendering of your interface.

Key Challenges:

Making multiple API calls without causing performance issues.

Ensuring user names are displayed as soon as data is fetched.

Handling states correctly in SwiftUI for responsive UI updates.

The Solution

To implement this solution, we will place the responsibility of fetching the user name within the QuestionView component. This localized approach allows each question to independently handle its API call, which maintains clarity and modularity in your code.

Step 1: Modify the QuestionView

First, let’s update the QuestionView to include a state variable for the user name. This variable will store the fetched name and ensure that your view updates correctly once the name is retrieved.

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Step 2: Set up the onAppear Method

Next, in the onAppear method of QuestionView, we'll add a function to call the user API. When the view appears, it will check if the name is already fetched and, if not, will make the API call to obtain the name using the senderId.

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

Step 3: Update the View with LazyVStack

Finally, let's make one more adjustment in the main view where you display the questions. Instead of using a VStack, you should use a LazyVStack, which will help optimize performance by loading only the elements currently visible on the screen.

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Summary of Steps

Define a @ State variable in QuestionView for the user name.

Implement an onAppear method to fetch the user name using the relevant API call.

Switch from VStack to LazyVStack for better performance.

Conclusion

By delegating the responsibility of fetching user names to the QuestionView, you can efficiently manage nested API calls in SwiftUI. This not only simplifies the overall architecture of your application but also enhances responsiveness and user experience.

Remember, optimizing API calls and managing state properly are crucial for building smooth and engaging SwiftUI applications. Implement these strategies in your next project to see noticeable improvements in performance and usability.