Autovalidate of TextFormField is deprecated in Flutter

autovalidate is replaced by autovalidateMode

Auto validation is deprecated and replaced by an enum. So you should migrate to the new version.

All you need to do is replace autovalidate: true with autovalidateMode: AutovalidateMode.always

The different supported modes are

1. AutovalidateMode.always
2. AutovalidateMode.disabled
3. AutovalidateMode.onUserInteraction

Example:

Code before migration:

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

Code after migration:

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

autovalidate is deprecated from Flutter v1.19

Replace autovalidate with autovalidateMode.

autovalidateMode can have one of the below 3 values:

1. autovalidateMode: AutovalidateMode.disabled: No auto validation will occur.

2. autovalidateMode: AutovalidateMode.always: Used to auto-validate FormField even without user interaction.

3. autovalidateMode: AutovalidateMode.onUserInteraction: Used to auto-validate FormField only after each user interaction.

I suggest try all the above values one by one and use the one that fulfills ur requirement.