Skip to main content

The new Form, FormField auto-validation API

Summary

#

The previous auto validation API for the Form and FormField widgets didn't control when auto validation should occur. So the auto validation for these widgets always happened on first build when the widget was first visible to the user, and you weren't able to control when the auto validation should happen.

Context

#

Due to the original API not allowing developers to change the auto validation behavior for validating only when the user interacts with the form field, we added new API that allows developers to configure how they want auto validation to behave for the Form and FormField widgets.

Description of change

#

The following changes were made:

  • The autovalidate parameter is deprecated.
  • A new parameter called autovalidateMode, an Enum that accepts values from the AutovalidateMode Enum class, is added.

Migration guide

#

To migrate to the new auto validation API you need to replace the usage of the deprecated autovalidate parameter to the new autovalidateMode parameter. If you want the same behavior as before you can use: autovalidateMode = AutovalidateMode.always. This makes your Form and FormField widgets auto validate on first build and every time it changes.

Code before migration:

dart 
class MyWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return FormField(
      autovalidate: true,
      builder: (FormFieldState state) {
        return Container();
      },
    );
  }
}

Code after migration:

dart 
class MyWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return FormField(
      autovalidateMode: AutovalidateMode.always,
      builder: (FormFieldState state) {
        return Container();
      },
    );
  }
}

Timeline

#

Landed in version: 1.21.0-5.0.pre
In stable release: 1.22

References

#

API documentation:

Relevant issues:

Relevant PRs:

Unless stated otherwise, the documentation on this site reflects Flutter 3.35.5. Page last updated on 2025-10-28. View source or report an issue.