The Complete Guide to Integrating Flutter Multiselect in Your Flutter App

Flutter has become a go-to framework for developing cross-platform applications with a single codebase. While Flutter provides a rich set of UI components, there are times when developers need to implement features that are not available out of the box.

One such feature is the ability to select multiple items from a list, commonly known as multi-select. The Flutter Multiselect package is a custom widget that fills this gap, offering a customizable and feature-rich solution for implementing multi-select widgets in a Flutter project.

Understanding Multi-Select Widgets in Flutter

Multi-select widgets are essential UI components that allow users to make multiple selections from a set of options. In Flutter, creating multi-select widgets can be challenging as the default widget library does not include a dedicated multi-select component. This is where the Flutter Multiselect package comes into play, providing developers with a ready-to-use multi-select widget that can be easily integrated and customized within their Flutter applications.

The Need for Custom Widgets in User Interfaces

Custom widgets are a cornerstone of creating a unique and functional user interface. They allow developers to tailor the UI components to the specific needs of their application. In multi-select widgets, customization can range from the visual design, such as choicechip style widgets, to the behavior, such as auto scroll or implementing more than one animation for a dynamic user experience.

The Flutter Multiselect package provides the functionality to create custom items within the dropdown and offers many customization options. Developers can design their button, define onTap function behavior, and utilize the onConfirm parameter to handle the selected values.

Implementing Flutter Multiselect in Your Flutter Project

Integrating the Flutter Multiselect package into your Flutter project allows you to offer users a seamless way to select multiple options from a list. This is particularly useful when you have a list of items like car brands or models and want to provide a multi-select option.

Getting Started with Flutter Multiselect

To kick things off with Flutter Multiselect, you must add the package to your project's pubspec.yaml file. This is the first step in bringing multi-select capabilities to your Flutter application.

Here's how you add the package to your pubspec.yaml file:

Copy
1dependencies:
2  flutter_multiselect: ^1.0.0
3

Once you've added the package, run the following command to get the package:

Copy
1flutter pub get
2

After fetching the package, import it in the Dart file where you want to use the multi-select widget:

Copy
1import 'package:flutter_multiselect/flutter_multiselect.dart';
2

With the package successfully imported, you can create multi-select widgets within your Flutter project.

Creating Multi Select Widgets with Flutter Multiselect

Creating multi-select widgets for a list of cars is straightforward with Flutter Multiselect. You can customize the widget to fit the look and feel of your app and configure it to handle the selected values appropriately.

Here's an example of how you might set up a multi-select widget for selecting car brands:

Copy
1MultiSelect(
2  autovalidate: false,
3  titleText: 'Select Car Brands',
4  validator: (value) {
5    if (value == null || value.isEmpty) {
6      return 'Please select one or more car brands';
7    }
8    return null;
9  },
10  dataSource: [
11    {"display": "Toyota", "value": "Toyota"},
12    {"display": "Ford", "value": "Ford"},
13    {"display": "BMW", "value": "BMW"},
14    // Add more car brands here
15  ],
16  textField: 'display',
17  valueField: 'value',
18  filterable: true,
19  required: true,
20  onSaved: (value) {
21    print('The selected car brands are $value');
22  }
23)
24

In this code snippet, dataSource is populated with a list of car brands, where a display and value pair represent each brand. The textField and valueField parameters tell the widget which fields to use for display and the underlying value, respectively. The validator ensures that the user makes at least one selection, and the onSaved callback is where you can handle the selected values, such as storing them or using them in another part of your application.

Advanced Customization and Usage of Flutter Multiselect

Once you have integrated the basic multi select functionality into your Flutter project, you should take advantage of the advanced customization options offered by the Flutter Multiselect package. These features allow you to create a more tailored user experience by building custom items for selection or leveraging additional form field features.

Leveraging FormField Features in Multi Select

The Flutter Multiselect widget also behaves like any other form field in Flutter, meaning it can take advantage of form field features. This includes using a Form widget to group multiple form fields, validating the entire form simultaneously, and using form-saving capabilities.

Here's an example of how you might use the Flutter Multiselect within a Form:

Copy
1Form(
2  key: _formKey,
3  child: Column(
4    children: <Widget>[
5      MultiSelect(
6        // Other properties...
7        onSaved: (value) {
8          // Handle the selected values
9        },
10        validator: (value) {
11          if (value == null || value.isEmpty) {
12            return 'Please select one or more car models';
13          }
14          return null;
15        },
16        // Other properties...
17      ),
18      ElevatedButton(
19        onPressed: () {
20          if (_formKey.currentState.validate()) {
21            _formKey.currentState.save();
22            // Process data
23          }
24        },
25        child: Text('Submit'),
26      ),
27    ],
28  ),
29)
30

In this example, the Form widget uses a GlobalKey to keep track of the form state. The MultiSelect widget is used as one of the form fields, complete with validation and saving logic. When the submit button is pressed, the form's current state is validated, and if the validation passes, the form's save method is called, which in turn calls the onSaved callback of each form field.

Conclusion

The Flutter Multiselect package is essential to any Flutter developer's toolkit, offering a customizable and user-friendly solution for implementing multi-select functionality. Its ease of integration and extensive customization options empower developers to create interfaces that efficiently cater to a wide range of use cases.

By leveraging this package, you can enhance the interactivity of your Flutter applications, providing users with a seamless multi-selection experience that feels both intuitive and native to the platform. Whether for simple forms or complex data filtering, Flutter Multiselect delivers a robust and flexible widget that will elevate the quality of your Flutter projects.