# flutter_form_builder

**Repository Path**: free_pan/flutter_form_builder

## Basic Information

- **Project Name**: flutter_form_builder
- **Description**: No description available
- **Primary Language**: Unknown
- **License**: MIT
- **Default Branch**: dependabot/pub/flutter_lints-3.0.0
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2023-11-06
- **Last Updated**: 2023-11-06

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# Flutter Form Builder

This package helps in creation of data collection forms in Flutter by removing the boilerplate needed to build a form, validate fields, react to changes and collect final user input.

Also included are common ready-made form input fields for FormBuilder. This gives you a convenient way of adding common ready-made input fields instead of creating your own FormBuilderField from scratch.

[![Pub Version](https://img.shields.io/pub/v/flutter_form_builder?logo=flutter&style=for-the-badge)](https://pub.dev/packages/flutter_form_builder)
[![GitHub Workflow Status](https://img.shields.io/github/actions/workflow/status/flutter-form-builder-ecosystem/flutter_form_builder/base.yaml?branch=main&logo=github&style=for-the-badge)](https://github.com/flutter-form-builder-ecosystem/flutter_form_builder/actions/workflows/base.yaml)
[![Codecov](https://img.shields.io/codecov/c/github/flutter-form-builder-ecosystem/flutter_form_builder?logo=codecov&style=for-the-badge)](https://codecov.io/gh/flutter-form-builder-ecosystem/flutter_form_builder/)
[![CodeFactor Grade](https://img.shields.io/codefactor/grade/github/flutter-form-builder-ecosystem/flutter_form_builder?logo=codefactor&style=for-the-badge)](https://www.codefactor.io/repository/github/flutter-form-builder-ecosystem/flutter_form_builder)
___

- [Features](#features)
- [Inputs](#inputs)
  - [Parameters](#parameters)
- [Use](#use)
  - [Setup](#setup)
  - [Basic use](#basic-use)
  - [Specific uses](#specific-uses)
    - [Validate and get values](#validate-and-get-values)
    - [Building your own custom field](#building-your-own-custom-field)
    - [Programmatically changing field value](#programmatically-changing-field-value)
    - [Programmatically inducing an error](#programmatically-inducing-an-error)
    - [Conditional validation](#conditional-validation)
    - [Implement reset, clear or other button into field](#implement-reset-clear-or-other-button-into-field)
- [Support](#support)
  - [Contribute](#contribute)
  - [Questions and answers](#questions-and-answers)
  - [Donations](#donations)
- [Roadmap](#roadmap)
- [Ecosystem](#ecosystem)
- [Thanks to](#thanks-to)

## Features

- Create a form with several type of inputs
- Get values from form by easy way
- Apply validators to inputs fields
- React to form fields changes and validations

| Complete Form | Sign Up | Dynamic Fields | Conditional Form |
|---|---|---|---|
| ![Gif demostration with all fields](https://raw.githubusercontent.com/flutter-form-builder-ecosystem/flutter_form_builder/main/screenshots/complete_form.gif) | ![Gif demostration sign up form](https://raw.githubusercontent.com/flutter-form-builder-ecosystem/flutter_form_builder/main/screenshots/signup.gif) | ![Gif demostration dynamic fields](https://raw.githubusercontent.com/flutter-form-builder-ecosystem/flutter_form_builder/main/screenshots/dynamic_fields.gif) | ![Gif demostration conditional fields](https://raw.githubusercontent.com/flutter-form-builder-ecosystem/flutter_form_builder/main/screenshots/conditional_fields.gif) |

## Inputs

The currently supported fields include:

- `FormBuilderCheckbox` - Single checkbox field
- `FormBuilderCheckboxGroup` - List of checkboxes for multiple selection
- `FormBuilderChoiceChip` - Creates a chip that acts like a radio button.
- `FormBuilderDateRangePicker` - For selection of a range of dates
- `FormBuilderDateTimePicker` - For `Date`, `Time` and `DateTime` input
- `FormBuilderDropdown` - Used to select one value from a list as a Dropdown
- `FormBuilderFilterChip` - Creates a chip that acts like a checkbox
- `FormBuilderRadioGroup` - Used to select one value from a list of Radio Widgets
- `FormBuilderRangeSlider` - Used to select a range from a range of values
- `FormBuilderSlider` - For selection of a numerical value on a slider
- `FormBuilderSwitch` - On/Off switch field
- `FormBuilderTextField` - A Material Design text field input

### Parameters

In order to create an input field in the form, along with the label, and any applicable validation, there are several attributes that are supported by all types of inputs namely:

| Attribute | Type  | Default | Required | Description |
|-----------|-------|---------|-------------|----------|
| `name` | `String` |  | `Yes` | This will form the key in the form value Map |
| `initialValue` | `T` | `null`  | `No` | The initial value of the input field |
| `enabled` | `bool` | `true` | `No` | Determines whether the field widget will accept user input. |
| `decoration` | `InputDecoration` | `InputDecoration()` | `No` | Defines the border, labels, icons, and styles used to decorate the field. |
| `validator` | `FormFieldValidator<T>` | `null` | `No` | A `FormFieldValidator` that will check the validity of value in the `FormField` |
| `onChanged` | `ValueChanged<T>` | `null` | `No` | This event function will fire immediately the the field value changes |
| `valueTransformer` | `ValueTransformer<T>` | `null` | `No` | Function that transforms field value before saving to form value. e.g. transform TextField value for numeric field from `String` to `num` |
The rest of the attributes will be determined by the type of Widget being used.

## Use

### Setup

No specific setup required: only install the dependency and use :)

### Basic use

```dart
final _formKey = GlobalKey<FormBuilderState>();

FormBuilder(
    key: _formKey,
    child:  FormBuilderTextField(
        name: 'text',
        onChanged: (val) {
            print(val); // Print the text value write into TextField
        },
    ),
)
```

See [pub.dev example tab](https://pub.dev/packages/flutter_form_builder/example) or [github code](example/lib/main.dart) for more details

### Specific uses

#### Validate and get values
  
  ```dart
  final _formKey = GlobalKey<FormBuilderState>();

  FormBuilder(
    key: _formKey,
    child: Column(
      children: [
        FormBuilderTextField(
          key: _emailFieldKey,
          name: 'email',
          decoration: const InputDecoration(labelText: 'Email'),
          validator: FormBuilderValidators.compose([
            FormBuilderValidators.required(),
            FormBuilderValidators.email(),
          ]),
        ),
        const SizedBox(height: 10),
        FormBuilderTextField(
          name: 'password',
          decoration: const InputDecoration(labelText: 'Password'),
          obscureText: true,
          validator: FormBuilderValidators.compose([
            FormBuilderValidators.required(),
          ]),
        ),
        MaterialButton(
          color: Theme.of(context).colorScheme.secondary,
          onPressed: () {
            // Validate and save the form values
            _formKey.currentState?.saveAndValidate();
            debugPrint(_formKey.currentState?.value.toString());

            // On another side, can access all field values without saving form with instantValues
            _formKey.currentState?.validate();
            debugPrint(_formKey.currentState?.instantValue.toString());
          },
          child: const Text('Login'),
        )
      ],
    ),
  ),
  ```

#### Building your own custom field

To build your own field within a `FormBuilder`, we use `FormBuilderField` which will require that you define your own field.
Read [this article](https://medium.com/@danvickmiller/building-a-custom-flutter-form-builder-field-c67e2b2a27f4) for step-by-step instructions on how to build your own custom field.

```dart
var options = ["Option 1", "Option 2", "Option 3"];
```

```dart
FormBuilderField(
  name: "name",
  validator: FormBuilderValidators.compose([
    FormBuilderValidators.required(),
  ]),
  builder: (FormFieldState<dynamic> field) {
    return InputDecorator(
      decoration: InputDecoration(
        labelText: "Select option",
        contentPadding:
            EdgeInsets.only(top: 10.0, bottom: 0.0),
        border: InputBorder.none,
        errorText: field.errorText,
      ),
      child: Container(
        height: 200,
        child: CupertinoPicker(
          itemExtent: 30,
          children: options.map((c) => Text(c)).toList(),
          onSelectedItemChanged: (index) {
            field.didChange(options[index]);
          },
        ),
      ),
    );
  },
),
```

#### Programmatically changing field value

You can either change the value of one field at a time like so:

```dart
_formKey.currentState.fields['color_picker'].didChange(Colors.black);
```

Or multiple fields value like so:

```dart
_formKey.currentState.patchValue({
  'age': '50',
  'slider': 6.7,
  'filter_chip': ['Test 1'],
  'choice_chip': 'Test 2',
  'rate': 4,
  'chips_test': [
    Contact(
        'Andrew', 
        'stock@man.com', 
        'https://d2gg9evh47fn9z.cloudfront.net/800px_COLOURBOX4057996.jpg',
    ),
  ],
});
```

#### Programmatically inducing an error

##### Using form state key or field state key

```dart
final _formKey = GlobalKey<FormBuilderState>();
final _emailFieldKey = GlobalKey<FormBuilderFieldState>();
...
FormBuilder(
  key: _formKey,
  child: Column(
    children: [
      FormBuilderTextField(
        key: _emailFieldKey,
        name: 'email',
        decoration: const InputDecoration(labelText: 'Email'),
        validator: FormBuilderValidators.compose([
          FormBuilderValidators.required(),
          FormBuilderValidators.email(),
        ]),
      ),
      ElevatedButton(
        child: const Text('Submit'),
        onPressed: () async {
          if(await checkIfEmailExists()){
            // Either invalidate using Form Key
            _formKey.currentState?.fields['email']?.invalidate('Email already taken');
            // OR invalidate using Field Key
            _emailFieldKey.currentState?.invalidate('Email already taken');
          }
        },
      ),
    ],
  ),
),
```

When use `invalidate` and `validate` methods, can use two optional parameters configure the behavior
when invalidate field or form, like focus or auto scroll. Take a look on method documentation for more details

##### Using InputDecoration.errorText

Declare a variable to hold your error:

```dart
String _emailError;
```

Use the variable as the `errorText` within `InputDecoration`

```dart
FormBuilderTextField(
  name: 'email',
  decoration: InputDecoration(
    labelText: 'Email',
    errorText: _emailError,
  ),
  validator: FormBuilderValidators.compose([
      FormBuilderValidators.required(),
      FormBuilderValidators.email(),
  ]),
),
```

Set the error text

```dart
RaisedButton(
  child: Text('Submit'),
  onPressed: () async {
    setState(() => _emailError = null);
    if(await checkIfEmailExists()){
      setState(() => _emailError = 'Email already taken.');
    }
  },
),
```

#### Conditional validation

You can also validate a field based on the value of another field

```dart
FormBuilderRadioGroup(
  decoration: InputDecoration(labelText: 'My best language'),
  name: 'my_language',
  validator: FormBuilderValidators.required(),
  options: [
    'Dart',
    'Kotlin',
    'Java',
    'Swift',
    'Objective-C',
    'Other'
  ]
    .map((lang) => FormBuilderFieldOption(value: lang))
    .toList(growable: false),
  ),
  FormBuilderTextField(
    name: 'specify',
    decoration:
        InputDecoration(labelText: 'If Other, please specify'),
    validator: (val) {
      if (_formKey.currentState.fields['my_language']?.value ==
              'Other' &&
          (val == null || val.isEmpty)) {
        return 'Kindly specify your language';
      }
      return null;
    },
  ),
```

#### Implement reset, clear or other button into field

If you can add some button to reset specific field, can use the `decoration` parameter like this:

```dart
List<String> genderOptions = ['Male', 'Female', 'Other'];

FormBuilderDropdown<String>(
  name: 'gender',
  initialValue: 'Male',
  decoration: InputDecoration(
    labelText: 'Gender',
    suffix: IconButton(
      icon: const Icon(Icons.close),
      onPressed: () {
        _formKey.currentState!.fields['gender']
            ?.reset();
      },
    ),
    hintText: 'Select Gender',
  ),
  items: genderOptions
      .map((gender) => DropdownMenuItem(
            alignment: AlignmentDirectional.center,
            value: gender,
            child: Text(gender),
          ))
      .toList(),
),
```

Or reset value like this:

```dart
class ClearFormBuilderTextField extends StatefulWidget {
  const ClearFormBuilderTextField({super.key});

  @override
  State<ClearFormBuilderTextField> createState() =>
      _ClearFormBuilderTextFieldState();
}

class _ClearFormBuilderTextFieldState
    extends State<ClearFormBuilderTextField> {
  final ValueNotifier<String?> text = ValueNotifier<String?>(null);
  final textFieldKey = GlobalKey<FormBuilderFieldState>();

  @override
  Widget build(BuildContext context) {
    return FormBuilderTextField(
      autovalidateMode: AutovalidateMode.always,
      name: 'age',
      key: textFieldKey,
      onChanged: (value) {
        text.value = value;
      },
      decoration: InputDecoration(
        labelText: 'Age',
        suffixIcon: ValueListenableBuilder<String?>(
          valueListenable: text,
          child: IconButton(
            onPressed: () => textFieldKey.currentState?.didChange(null),
            tooltip: 'Clear',
            icon: const Icon(Icons.clear),
          ),
          builder: (context, value, child) =>
              (value?.isEmpty ?? true) ? const SizedBox() : child!,
        ),
      ),
    );
  }
}
```

## Support

### Contribute

You have some ways to contribute to this packages

- Beginner: Reporting bugs or request new features
- Intermediate: Implement new features (from issues or not) and created pull requests
- Advanced: Join to [organization](#ecosystem) like a member and help coding, manage issues, dicuss new features and other things

 See [contribution file](https://github.com/flutter-form-builder-ecosystem/.github/blob/main/CONTRIBUTING.md) for more details

### Questions and answers

You can question or search answers on [Github discussion](https://github.com/flutter-form-builder-ecosystem/flutter_form_builder/discussions) or on [StackOverflow](https://stackoverflow.com/questions/tagged/flutter-form-builder)

### Donations

Donate or become a sponsor of Flutter Form Builder Ecosystem

[![Become a Sponsor](https://opencollective.com/flutter-form-builder-ecosystem/tiers/sponsor.svg?avatarHeight=56)](https://opencollective.com/flutter-form-builder-ecosystem)

## Roadmap

- [Solve open issues](https://github.com/flutter-form-builder-ecosystem/flutter_form_builder/issues), [prioritizing bugs](https://github.com/flutter-form-builder-ecosystem/flutter_form_builder/labels/bug)

## Ecosystem

Take a look to [our awesome ecosystem](https://github.com/flutter-form-builder-ecosystem) and all packages in there

## Thanks to

[All contributors](https://github.com/flutter-form-builder-ecosystem/flutter_form_builder/graphs/contributors)