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Learn how to implement a `domain-based email validation` in your Flutter app's login form to ensure users enter valid emails ending with your specified domain.
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How to Add a Specific Domain Validator in Your Flutter Form

In developing efficient forms within Flutter applications, it's crucial to ensure that inputs meet specific requirements. For instance, if you have a login page that should only accept emails from a particular domain, configuring a custom email validator is essential. In this guide, we'll explore how to implement a domain-specific email validation in your Flutter app's form.

The Problem

You might find yourself in a situation where you want to restrict email inputs to a specific domain, such as @ abc.net, within your Flutter login page. The standard text input validation may not suffice, necessitating a custom solution. Fortunately, Flutter allows you to implement this with ease.

Example of Current Code

To lay the groundwork, here’s a snippet of the code you may have already started with for your email input:

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Now, let's enhance this code to add domain-specific validation.

The Solution

Method 1: Simple String Check

The first method for validating the email based on a specific domain is quite straightforward. You can use the endsWith method to check whether the email input ends with @ your_domain.com. Here's how you can modify the validator function:

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This method effectively ensures that only emails ending with @ abc.net will be accepted.

Method 2: Regular Expressions (RegEx)

For a more robust solution, especially if you plan to account for more complex email validation, you can use Regular Expressions. Regular expressions provide a powerful way to define patterns. Here’s how you can implement this:

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Explanation of the Regular Expression

^ and $ denote the start and end of the string, respectively.

[a-zA-Z0-9._%+ -]+ matches the local part of the email.

@ abc.net ensures that the domain matches exactly with abc.net, whereas the backslash (\) is used to escape the dot (.).

Validation Testing

You can also test the regex using some examples:

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In this case, you can see that emails like sdfsdf@ abc.net are valid, while others are rejected.

Conclusion

Adding a specific domain validator in your Flutter form is an excellent way to ensure that you're collecting valid data from users. By leveraging simple string checks and regular expressions, you can easily enforce domain restrictions for your email inputs. Adjusting your validation logic thus not only enhances your application's integrity but also improves user experience by guiding users toward appropriate input.

Remember to replace @ abc.net with the specific domain name you require. Happy coding!