How to Create Flutter Forms?

Introduction

Mobile applications rely on user input for various purposes, be it logging in, submitting data, or providing feedback. To create a smooth and engaging user experience, developers need a reliable way to collect and validate user input. This is where Flutter Forms come to the rescue.

Flutter Forms offer a comprehensive set of tools and widgets that simplify the process of building interactive and responsive forms. In this article, we will explore the features and benefits of Flutter Forms, demonstrate how to handle form submissions, and style forms, and provide best practices for designing user-friendly forms.

Flutter Forms

Flutter provides a set of tools, widgets, and libraries that make it easier to create and handle forms within a Flutter application. It offers widgets such as Form, TextFormField, and DropdownButtonFormField that handle common form elements and come with built-in validation and error-handling capabilities. Additionally, developers can customize the appearance of form elements and leverage third-party libraries for extended functionalities. Testing support is also provided to ensure the proper functioning of form validation and user interactions.

Handling Form Submissions

Handling form submissions involves creating a form widget, defining form fields, validating input, and processing the form data. Here's a step-by-step guide on how to handle form submissions in Flutter:

Step - 1: Create a Form with a GlobalKey

The Form widget acts as a container for grouping and validating multiple form fields. When creating the form, provide a GlobalKey that uniquely identifies the Form and allows validation of the form in a later step.

Step - 2: Add a TextFormField with validation logic

The TextFormField widget renders a material design text field and can display validation errors when they occur. Validate the input by providing a validator function to the TextFormField.

Step - 3: Create a button to validate and submit the form

Create a button widget, such as ElevatedButton, that triggers the validation and submission of the form when pressed. Inside the onPressed callback, call the validate() method on the GlobalKey assigned to the Form. If the form is valid, process the form data or perform other necessary operations.

Styling the Form

When creating a form in Flutter, it’s important to not only focus on its functionality but also its appearance. A well-designed form can improve the user experience and make it easier for users to enter and submit information.

1. Spacing and Padding:

   Add spacing and padding to form fields to improve readability, using SizedBox and Padding widgets.

2. Colors:

   Choose colors that align with your app's theme and create a visually pleasing form. You can customize the colors of the form fields, labels, hints, and buttons using the color and decoration properties.

3. Fonts:

   Choose appropriate font sizes and styles for your form to ensure readability. You can modify the font properties of the form fields using the style property.

4. Labels and Hints:

   Provide clear labels and helpful hints for each form field. You can customize the labels and hints using the labelText and hintText properties of the InputDecoration class.

5. Input Types:

   Choose appropriate input types for each form field to improve user experience. Use input types like keyboardType, inputFormatters, or specific input widgets for fields like dates or dropdown menus.

Creating a Form

Example

Code Explanation

• MyFormPage represents the form page and contains the form fields and a submit button.
• To manage the form's state, a special key called _formKey is used.
• Inside the form, TextFormField widgets are used for the name and email fields, allowing users to enter their information.
• A button is provided to submit the form, and when pressed, the data is logged to the console. This allows developers to test and debug the form easily.

Creating a Form with Validation

Example

Code Explanation

• The validator property of each TextFormField is used to validate the input values. If the field is empty or does not match the required format (for email), an error message is returned.
• The Submit button is wrapped in a Container and ElevatedButton widget. When clicked, it checks if the form is valid based on the validation logic. If valid, the _submitForm function is called.
• The _submitForm function is currently set to print a message, but you can replace it with your logic to handle the form submission.

Overall, this code sets up a basic form with validation for the Name and Email fields, ensuring that the user provides the required information before submitting the form.

Best Practices for Form Design

When designing forms, it's important to consider the user experience and ensure that the form is intuitive, user-friendly, and encourages successful completion. Here are some best practices for form design:

1. Keep it simple:

Minimize the number of form fields and only ask for essential information. Users are more likely to complete shorter forms.

2. Use clear and concise labels:

Clearly label each form field using descriptive text that is easy to understand. Avoid technical jargon or ambiguous terms.

3. Provide inline validation:

Validate user input as they fill out the form by providing real-time feedback. Highlight errors immediately and offer suggestions for correction.

4. Use placeholder text sparingly:

Placeholder text within form fields can be useful for providing examples or guidance, but it should not replace clear labels. Placeholder text should disappear when the user starts typing.

5. Prioritize accessibility:

Ensure that your form is accessible to users with disabilities. Use proper form field labeling, provide clear instructions, and allow for keyboard navigation.

6. Use appropriate input controls:

Choose the right input controls for each field type. For example, use dropdown menus for selecting options, radio buttons for mutually exclusive choices, and date pickers for date input.