How to Dynamically Build Rich Text with FutureBuilder in Flutter

Discover how to handle asynchronous data retrieval in Flutter using FutureBuilder and improve your UI code for a better user experience.
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How to Dynamically Build Rich Text with FutureBuilder in Flutter

Building a responsive and interactive UI in your Flutter applications can sometimes become quite challenging, especially when dealing with asynchronous data retrieval. In this guide, we will explore a specific problem: how to dynamically build rich text that fetches user display names based on tagged mentions in a comment. We’ll also address common issues you might face with FutureBuilder and provide a clear step-by-step solution.

The Problem

Imagine you have a comment section in your Flutter app where users can mention others by using the '@ ' symbol (like @ username). Your goal is to dynamically replace these mentions with the corresponding user display names fetched asynchronously. However, you run into an issue where your FutureBuilder keeps returning null, causing an error in your app.

The error message you receive is:

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

Solution Overview

Here, we’ll improve the way you use FutureBuilder and enhance your code to ensure a smooth user experience.

Here's how you can modify your builder method:

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

2. Persist the Future in State

To avoid recreating the future every build cycle (which can cause unnecessary data fetching), keep the Future as a field in your state class. When the underlying data changes (e.g., the comment text), you should set the future accordingly. For instance:

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

3. Separate Data Retrieval from UI Code

It’s a good practice to separate your async data fetching logic from your UI code. Move the data retrieval code out of the build function. Here’s a better approach for the FutureBuilder:

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

4. The Data Retrieval Function

Lastly, you need to create a function that actually retrieves the user display names. This function will look like this:

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

Putting It All Together

By following these steps, you will not only resolve the issue with your FutureBuilder returning null, but you'll also create a more efficient and streamlined codebase that enhances the overall user experience.

Conclusion

By following the guidelines laid out in this post, you will be able to dynamically build rich text and handle user mentions without any hiccups. Happy coding!