Скачать или смотреть Resolving Form Validation not Hitting Function Call in Flutter

Explore common issues with form validation in Flutter and learn how to effectively call asynchronous functions when a form is valid.
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This video is based on the question https://stackoverflow.com/q/75606723/ asked by the user 'Spencer Martel' ( https://stackoverflow.com/u/19841598/ ) and on the answer https://stackoverflow.com/a/75606849/ provided by the user 'Md. Yeasin Sheikh' ( https://stackoverflow.com/u/10157127/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Troubleshooting Form Validation in Flutter

As a developer working with Flutter, you might encounter some tricky situations when implementing form validation and asynchronous function calls. One common issue that arises is the async function not firing after your form has been validated. If you find yourself hitting the print statement but not seeing the expected result from your async function, you are not alone. This post will guide you through understanding and resolving this problem in a clear and concise manner.

The Problem: Async Function Not Firing

In the provided code snippet, the developer is trying to validate a form and call an asynchronous function if the form is valid. However, the intent to execute the async function is not being met. Here’s the relevant portion of the code:

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

While the developer correctly checks if the form is valid, they mistakenly create an inline function without invoking it. This can lead to confusion, as the function intended to execute the sign-in logic is simply defined but never called.

The Solution: Refactor the Code

To resolve the issue, you must correctly call the asynchronous function right after confirming that the form is valid and eliminate unnecessary nesting. Here’s how to refactor your code:

Step 1: Simplify the Tap Handler

You need to directly place the async logic inside the onTap parameter. Here’s the corrected version of the code:

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

Key Changes Made

Direct Async Function Call: Instead of creating a nested function with () async {} that is never called, place the async logic directly in the onTap method.

Validation and Loading State Handling: The validated state is checked, and loading states (using isLoading) are updated seamlessly within a single flow.

Conclusion

By restructuring your code to ensure that the async function is executed properly, you can effectively resolve the issue of the function not firing after validation. This not only clears up confusion but also enhances the readability and maintainability of your code.

Feel free to utilize this pattern in your future Flutter projects for managing form validation and async operations. Happy coding!