Custom Input Formatter

A Flutter package providing advanced input formatters for various number formats including amounts, phone numbers, credit cards, and more. This formatter offers flexible formatting options with customizable separators and grouping patterns.

Features

The package provides comprehensive formatting support for various numeric input types:

  • Amount formatting with thousand separators
  • Phone number formatting with customizable patterns
  • Credit card number formatting (4-digit groups)
  • Social security number formatting
  • Bank account number formatting
  • Date formatting (DD MM YYYY)
  • Time formatting (HH MM SS)
  • Postal code validation
  • Generic number formatting with custom patterns

Installation

Add this to your package's pubspec.yaml file:

dependencies:
  custom_input_formatter: ^2.0.0

Basic Usage

Format Types

The formatter supports multiple predefined format types:

TextField(
  inputFormatters: [
    CustomNumberInputFormatter(
      formatType: FormatType.amount,
    ),
  ],
  keyboardType: TextInputType.number,
)

Available format types include:

  • FormatType.amount - For currency amounts (e.g., "1 000 000")
  • FormatType.phoneNumber - For phone numbers (e.g., "07 98 87 66 77")
  • FormatType.creditCard - For credit card numbers (e.g., "4242 4242 4242 4242")
  • FormatType.socialSecurity - For social security numbers (e.g., "123-45-6789")
  • FormatType.bankAccount - For bank account numbers
  • FormatType.date - For dates (e.g., "31 12 2024")
  • FormatType.time - For time (e.g., "23 59 59")
  • FormatType.postalCode - For postal codes
  • FormatType.number - For generic numbers

Advanced Usage

Custom Formatting Patterns

You can create custom formatting patterns by specifying the separator and group size:

// Custom grouping pattern (e.g., XX-XXX-XX)
TextField(
  inputFormatters: [
    CustomNumberInputFormatter(
      separator: '-',
      groupBy: 2,
      maxLength: 7,
    ),
  ],
)

Bank Account Number Formatting

TextField(
  inputFormatters: [
    CustomNumberInputFormatter(
      formatType: FormatType.bankAccount,
      // Will automatically use the pattern: XXXX XXXX XXXX XXXX XXXX XXX
    ),
  ],
)

Date Input Formatting

TextField(
  inputFormatters: [
    CustomNumberInputFormatter(
      formatType: FormatType.date,
      // Will automatically format as: DD MM YYYY
    ),
  ],
)

Properties

The CustomNumberInputFormatter class accepts the following properties:

Property Type Default Description
separator String ' ' Character used to separate groups
groupBy int 3 Number of characters in each group
maxLength int? null Maximum length (excluding separators)
formatType FormatType FormatType.number Type of formatting to apply

Default Maximum Lengths

Each format type comes with predefined maximum lengths:

  • Credit Card: 16 digits
  • Social Security: 9 digits
  • Postal Code: 5 digits
  • Date: 8 digits (DDMMYYYY)
  • Time: 6 digits (HHMMSS)

Format-Specific Grouping Patterns

Pre-configured grouping patterns for specific formats:

  • Credit Card: 4, 4, 4, 4
  • Social Security: 3, 2, 4
  • Bank Account: 4, 4, 4, 4, 4, 3
  • Date: 2, 2, 4
  • Time: 2, 2, 2

Examples

Amount Formatting

// Input: "1000000"
// Output: "1 000 000"
TextField(
  inputFormatters: [
    CustomNumberInputFormatter(
      formatType: FormatType.amount,
    ),
  ],
)

Credit Card Input

// Input: "4242424242424242"
// Output: "4242 4242 4242 4242"
TextField(
  inputFormatters: [
    CustomNumberInputFormatter(
      formatType: FormatType.creditCard,
    ),
  ],
)

Social Security Number

// Input: "123456789"
// Output: "123-45-6789"
TextField(
  inputFormatters: [
    CustomNumberInputFormatter(
      formatType: FormatType.socialSecurity,
    ),
  ],
)

Best Practices

  1. Always specify the appropriate keyboard type:
keyboardType: TextInputType.number
  1. Consider combining with other formatters for additional validation:
inputFormatters: [
  FilteringTextInputFormatter.digitsOnly,
  CustomNumberInputFormatter(
    formatType: FormatType.amount,
  ),
],
  1. Handle empty and invalid inputs appropriately in your form validation logic.

Contribution

Contributions are welcome! Please feel free to submit a Pull Request.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Libraries

custom_input_formatter