base on Simple form maker for Flutter Framework # 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. [](https://pub.dev/packages/flutter_form_builder) [](https://github.com/flutter-form-builder-ecosystem/flutter_form_builder/actions/workflows/base.yaml) [](https://codecov.io/gh/flutter-form-builder-ecosystem/flutter_form_builder/) [](https://www.codefactor.io/repository/github/flutter-form-builder-ecosystem/flutter_form_builder) ___ ## Call for Maintainers > We are looking for maintainers to contribute to the development and maintenance of Flutter Form Builder Ecosystem. Is very important to keep the project alive and growing, so we need your help to keep it up to date and with new features. You can contribute in many ways, we describe some of them in [Support](#support) section. - [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 | |---|---|---|---| |  |  |  |  | ## 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 Note: Validators are in a separate package ([form_builder_validators](https://pub.dev/packages/form_builder_validators)). ```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', '[email protected]', '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 ElevatedButton( 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 [](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) ", Assign "at most 3 tags" to the expected json: {"id":"9895","tags":[]} "only from the tags list I provide: [{"id":77,"name":"3d"},{"id":89,"name":"agent"},{"id":17,"name":"ai"},{"id":54,"name":"algorithm"},{"id":24,"name":"api"},{"id":44,"name":"authentication"},{"id":3,"name":"aws"},{"id":27,"name":"backend"},{"id":60,"name":"benchmark"},{"id":72,"name":"best-practices"},{"id":39,"name":"bitcoin"},{"id":37,"name":"blockchain"},{"id":1,"name":"blog"},{"id":45,"name":"bundler"},{"id":58,"name":"cache"},{"id":21,"name":"chat"},{"id":49,"name":"cicd"},{"id":4,"name":"cli"},{"id":64,"name":"cloud-native"},{"id":48,"name":"cms"},{"id":61,"name":"compiler"},{"id":68,"name":"containerization"},{"id":92,"name":"crm"},{"id":34,"name":"data"},{"id":47,"name":"database"},{"id":8,"name":"declarative-gui "},{"id":9,"name":"deploy-tool"},{"id":53,"name":"desktop-app"},{"id":6,"name":"dev-exp-lib"},{"id":59,"name":"dev-tool"},{"id":13,"name":"ecommerce"},{"id":26,"name":"editor"},{"id":66,"name":"emulator"},{"id":62,"name":"filesystem"},{"id":80,"name":"finance"},{"id":15,"name":"firmware"},{"id":73,"name":"for-fun"},{"id":2,"name":"framework"},{"id":11,"name":"frontend"},{"id":22,"name":"game"},{"id":81,"name":"game-engine "},{"id":23,"name":"graphql"},{"id":84,"name":"gui"},{"id":91,"name":"http"},{"id":5,"name":"http-client"},{"id":51,"name":"iac"},{"id":30,"name":"ide"},{"id":78,"name":"iot"},{"id":40,"name":"json"},{"id":83,"name":"julian"},{"id":38,"name":"k8s"},{"id":31,"name":"language"},{"id":10,"name":"learning-resource"},{"id":33,"name":"lib"},{"id":41,"name":"linter"},{"id":28,"name":"lms"},{"id":16,"name":"logging"},{"id":76,"name":"low-code"},{"id":90,"name":"message-queue"},{"id":42,"name":"mobile-app"},{"id":18,"name":"monitoring"},{"id":36,"name":"networking"},{"id":7,"name":"node-version"},{"id":55,"name":"nosql"},{"id":57,"name":"observability"},{"id":46,"name":"orm"},{"id":52,"name":"os"},{"id":14,"name":"parser"},{"id":74,"name":"react"},{"id":82,"name":"real-time"},{"id":56,"name":"robot"},{"id":65,"name":"runtime"},{"id":32,"name":"sdk"},{"id":71,"name":"search"},{"id":63,"name":"secrets"},{"id":25,"name":"security"},{"id":85,"name":"server"},{"id":86,"name":"serverless"},{"id":70,"name":"storage"},{"id":75,"name":"system-design"},{"id":79,"name":"terminal"},{"id":29,"name":"testing"},{"id":12,"name":"ui"},{"id":50,"name":"ux"},{"id":88,"name":"video"},{"id":20,"name":"web-app"},{"id":35,"name":"web-server"},{"id":43,"name":"webassembly"},{"id":69,"name":"workflow"},{"id":87,"name":"yaml"}]" returns me the "expected json"