number_editing_controller

A Flutter TextEditingController that automatically formats numbers, decimals, and currencies as the user types. Built with full locale support.

Developed by nerdy.pro.

Features

• As-you-type formatting for integers, decimals, and currency amounts
• Locale-aware grouping and decimal separators (e.g. 1,234.56 in English, 1.234,56 in German)
• Currency support with automatic symbol placement based on locale
• Extracts the numeric value via controller.number
• Negative number support with optional allowNegative flag
• Custom separators for decimal and grouping characters

Getting started

Install the package:

flutter pub add number_editing_controller

Usage

Create a controller and assign it to a TextField:

final controller = NumberEditingTextController.currency(currencyName: 'USD');

TextField(
  controller: controller,
  keyboardType: TextInputType.numberWithOptions(decimal: true, signed: true),
)

Read the numeric value at any time:

final value = controller.number; // e.g. 1234.56

Integer input

final controller = NumberEditingTextController.integer();

Decimal input

final controller = NumberEditingTextController.decimal();

Currency input

final controller = NumberEditingTextController.currency(currencyName: 'EUR');

Configuration options

All constructors accept the following parameters:

Parameter	Description
locale	Locale for number formatting (e.g. 'en', 'de', 'ja'). Defaults to the current locale.
allowNegative	Whether to allow negative numbers. Defaults to true.
groupSeparator	Custom digit grouping symbol (e.g. ',', '.', ' ').
value	Initial numeric value.

The currency() constructor also accepts:

Parameter	Description
currencyName	ISO 4217 currency code (e.g. 'USD', 'EUR', 'JPY').
currencySymbol	Custom currency symbol (e.g. '$', '€', '₺').
decimalSeparator	Custom decimal separator symbol.

The decimal() constructor also accepts:

Parameter	Description
minimalFractionDigits	Minimum number of decimal digits to display.
maximumFractionDigits	Maximum number of decimal digits allowed.
decimalSeparator	Custom decimal separator symbol.

Examples

// US Dollar with locale
final usd = NumberEditingTextController.currency(
  currencyName: 'USD',
  locale: 'en',
);

// Euro in German locale
final eur = NumberEditingTextController.currency(
  currencyName: 'EUR',
  locale: 'de',
);

// Positive-only integer
final positive = NumberEditingTextController.integer(
  allowNegative: false,
);

// Decimal with precision control
final precise = NumberEditingTextController.decimal(
  minimalFractionDigits: 2,
  maximumFractionDigits: 4,
  locale: 'en',
);

A working example app is available in the example directory.

Disposing the controller

Like any TextEditingController, dispose of it when it is no longer needed:

@override
void dispose() {
  controller.dispose();
  super.dispose();
}