Creating Masked Text Inputs in Flutter with flutter_masked_text

Welcome to another Flutter development blog post! Today, we will explore the flutter_masked_text plugin, which provides a convenient way to create masked text inputs in your Flutter applications. Masked text inputs are particularly useful when you want to enforce a specific format for user input, such as phone numbers, credit card numbers, or dates.

Getting Started

To get started with flutter_masked_text, you need to add the package as a dependency in your pubspec.yaml file:

dependencies:
  flutter_masked_text: ^x.x.x  # Replace with the latest version
  

Once you have added the package, run flutter pub get to fetch the latest version of the package from the pub.dev repository.

Creating a Masked Text Input

Now that we have the package installed, let's create a masked text input. First, import the necessary classes:

import 'package:flutter/material.dart';
import 'package:flutter_masked_text/flutter_masked_text.dart';
  

Next, define a TextEditingController and a mask for your desired format. For example, if you want to create a masked input for a phone number, you can use the following code:

TextEditingController controller = MaskedTextController(mask: '(000) 000-0000');
  

With the controller in place, you can now use it in a TextField widget:

TextField(
  controller: controller,
  decoration: InputDecoration(
    labelText: 'Phone Number',
  ),
)
  

The mask property specifies the format of the input, where 0 represents a digit. Any other characters in the mask will be fixed and cannot be changed by the user.

Common Questions

1. How can I create a masked input for a credit card number?

To create a masked input for a credit card number, you can use the following mask: '0000 0000 0000 0000'. This mask enforces a 16-digit format with spaces after every 4 digits.

TextEditingController controller = MaskedTextController(mask: '0000 0000 0000 0000');
  

2. Can I customize the placeholder character used in the mask?

Yes, you can customize the placeholder character by setting the placeholder property of the MaskedTextController. For example, if you want to use an underscore (_) as the placeholder, you can do the following:

TextEditingController controller = MaskedTextController(mask: '00/00/0000', placeholder: '_');
  

3. How can I retrieve the raw unmasked text from the controller?

You can get the unmasked text from the controller using the text property. For example:

String unmaskedText = controller.text;
  

By accessing the text property, you will obtain the raw unmasked input without any formatting characters.

Advanced Usage

The flutter_masked_text package offers additional features and customization options for masked text inputs. Let's explore some of these advanced techniques:

Custom Validation

By default, flutter_masked_text provides basic validation based on the mask format. However, you can also implement custom validation logic using the validator parameter of the TextField widget.

TextField(
  controller: controller,
  decoration: InputDecoration(
    labelText: 'Phone Number',
  ),
  validator: (value) {
    // Custom validation logic here
    if (value.isEmpty) {
      return 'Phone number is required';
    }
    // Add more validation rules if needed
    return null;
  },
)
  

Masked Form Fields

If you have multiple masked text inputs in a form, you can use the Form widget along with TextFormField to simplify the validation and submission process.

final GlobalKey _formKey = GlobalKey();

// ...

Form(
  key: _formKey,
  child: Column(
    children: [
      TextFormField(
        controller: controller1,
        decoration: InputDecoration(
          labelText: 'Phone Number',
        ),
        validator: (value) {
          // Custom validation logic for the phone number
          // ...
        },
      ),
      TextFormField(
        controller: controller2,
        decoration: InputDecoration(
          labelText: 'Email Address',
        ),
        validator: (value) {
          // Custom validation logic for the email address
          // ...
        },
      ),
      // Add more form fields if needed
    ],
  ),
)

// ...

ElevatedButton(
  onPressed: () {
    if (_formKey.currentState.validate()) {
      // Submit the form if all fields are valid
    }
  },
  child: Text('Submit'),
)
  

Conclusion

In this blog post, we have learned how to use the flutter_masked_text plugin to create masked text inputs in Flutter. We explored the process of setting up the package, creating a masked input, addressing common questions regarding customizations and retrieving unmasked text, and delved into advanced usage scenarios.

Masked text inputs are a powerful tool in ensuring consistent and valid user input. With the help of flutter_masked_text, you can easily implement masked inputs in your Flutter applications, saving time and effort.

For more information and detailed usage instructions, check out the official documentation of the flutter_masked_text package.