Getting Started

Master validator is meant to be used when working with forms generally. The library provides a set of pre-written validator functions which you can give as a value to the validator argument of your text form field widget

Import master_validator package

import 'package:master_validator/master_validator.dart';

Usage

Basic Required Field Validation

Use Validators.Required() to make a field required.

TextFormField(
    validator: Validators.Required(
        errorMessage : "This field cannot be left empty",
    )
),

Email Validation :

TextFormField(
    validator: Validators.Required(
        next : Validators.Email(),
    ),
),

Using Multiple Validators (Chaining Validators)

All validators take a next argument in which you can specify another validator (a custom function, or another predefined validator) like :

TextFormField(
    validator: Validators.Required(
        next : Validators.Email(
            next : Validators.Maxlength(50)
        ),
    ),
),

Finally

Finally, to validate your form, just call validate method from your form's key :

// supply the Form widget with the key
Form(
    key : _formKey,
    child : Column(),
)

// validate form inside some function
if (_formKey.currentState!.validate()) {
    showSnackbar("Form is valid");
} else {
    showSnackbar("Form is invalid");
}

Extra

Master Validator by default also adds up the following extensions to String class :

isEmail
isInteger
isDouble
isValidDirectoryName
isValidURL
hasLengthBetween(min,max) All of these returns a boolean value which can be used as :

String email = "someone@org.com";

if(email.isEmail){
    print("Valid Email");
}

For detailed usage, check example

Last modified: 05 January 2024