the_validator 1.0.1

  • Readme
  • Changelog
  • Example
  • Installing
  • 81

The Validator #

A simple & lightweight form and data validation package for flutter

How to use #

The Validator can be used directly on a TextFormField validator parameter TextFormField(validator:

The Validator can also be used as a stand alone validator Validatror.isPassword('SecretPass', shouldContainCapitalLetter: true)

Sample Usage (FieldValidator) #

    controller: _emailController,
    decoration: InputDecoration(labelText: "Email"),
    controller: _passwordController,
        validator: FieldValidator.password(
        minLength: 8,
        shouldContainNumber: true,
        shouldContainCapitalLetter: true,
        shouldContainSpecialChars: true,
        errorMessage: "Password must match the required format",
        isNumberNotPresent: () { return "Password must contain number"; },
        isSpecialCharsNotPresent: () { return "Password must contain special characters"; },
        isCapitalLetterNotPresent: () { return "Password must contain capital letters"; }
        decoration: InputDecoration(labelText: "Email"),

Then make a call to .validate() to perform

  onPressed: () {
    // validate() inputed data
    if (_formKey.currentState.validate()) {

          .showSnackBar(SnackBar(content: Text("Yay! we got it right!")));
  child: Text("Submit"),                  

Sample Usage 2 (Validator) #

var password = 'Secret'
var confirmPassword = 'secret'
if (Validator.isPassword(password, shouldContainCapitalLetter: true)) {
  if (Validator.isEqualTo(password, confirmPassword)) {
    print("Go ahead & grant access")
  } else {
    print("Password mis match")

Error messages #

By default The Validator will give you a nice default error based on the the type of validation you specify for field or an input. But you can also override the default message

Default Error Messages

FieldValidator.alphaNumeric() will output Field must contain both alphabets and numbers

User Defined Error Message

FieldValidator.alphaNumeric(message: 'Your username must contain both numbers & alphabets')

[1.0.1] #

  • stops email validation from accepting e.g myemail@gmail as a valid email
  • set custom error message on individual password validation rules

[1.0.0] #

  • Fixed failing validation on password form fields
  • MinLength & MaxLength validation fix
  • Version 1 ready

[0.0.2] #

  • Added test for minLength()
  • Updated the readme & info

[0.0.1] #

  • Initial Release
  • TODO (Features):
  • Add Url Validation
  • Add Date Validation
  • Add Credit card Validation


// import 'package:example/FormScreen.dart';
import 'package:flutter/material.dart';

import 'FormScreen.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        // This is the theme of your application.
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
      home: FormScreen(),

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;

  _MyHomePageState createState() => _MyHomePageState();

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  void _incrementCounter() {
    setState(() {
      // This call to setState tells the Flutter framework that something has
      // changed in this State, which causes it to rerun the build method below
      // so that the display can reflect the updated values. If we changed
      // _counter without calling setState(), then the build method would not be
      // called again, and so nothing would appear to happen.

  Widget build(BuildContext context) {
    // This method is rerun every time setState is called, for instance as done
    // by the _incrementCounter method above.
    // The Flutter framework has been optimized to make rerunning build methods
    // fast, so that you can just rebuild anything that needs updating rather
    // than having to individually change instances of widgets.
    return Scaffold(
      appBar: AppBar(
        // Here we take the value from the MyHomePage object that was created by
        // the method, and use it to set our appbar title.
        title: Text(widget.title),
      body: Center(
        // Center is a layout widget. It takes a single child and positions it
        // in the middle of the parent.
        child: Column(
          // Column is also a layout widget. It takes a list of children and
          // arranges them vertically. By default, it sizes itself to fit its
          // children horizontally, and tries to be as tall as its parent.
          // Invoke "debug painting" (press "p" in the console, choose the
          // "Toggle Debug Paint" action from the Flutter Inspector in Android
          // Studio, or the "Toggle Debug Paint" command in Visual Studio Code)
          // to see the wireframe for each widget.
          // Column has various properties to control how it sizes itself and
          // how it positions its children. Here we use mainAxisAlignment to
          // center the children vertically; the main axis here is the vertical
          // axis because Columns are vertical (the cross axis would be
          // horizontal).
          children: <Widget>[
              'You have pushed the button this many times:',
              style: Theme.of(context).textTheme.display1,
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.

Use this package as a library

1. Depend on it

Add this to your package's pubspec.yaml file:

  the_validator: ^1.0.1

2. Install it

You can install packages from the command line:

with Flutter:

$ flutter pub get

Alternatively, your editor might support flutter pub get. Check the docs for your editor to learn more.

3. Import it

Now in your Dart code, you can use:

import 'package:the_validator/the_validator.dart';
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Learn more about scoring.

We analyzed this package on Mar 27, 2020, and provided a score, details, and suggestions below. Analysis was completed with status completed using:

  • Dart: 2.7.1
  • pana: 0.13.6
  • Flutter: 1.12.13+hotfix.8

Health suggestions

Fix lib/the_validator.dart. (-0.50 points)

Analysis of lib/the_validator.dart reported 1 hint:

line 10 col 7: This class (or a class which this class inherits from) is marked as '@immutable', but one or more of its instance fields are not final: ErrorLabel.text


Package Constraint Resolved Available
Direct dependencies
Dart SDK >=2.1.0 <3.0.0
flutter 0.0.0
Transitive dependencies
collection 1.14.11 1.14.12
meta 1.1.8
sky_engine 0.0.99
typed_data 1.1.6
vector_math 2.0.8
Dev dependencies