amount_localizer

Locale-aware amount formatter for Flutter, with a small native bridge that reads the device's true Region setting (iOS) / format-locale country (Android) — the setting that actually drives the numeric keyboard's decimal key.

Flutter's PlatformDispatcher.instance.locale only exposes the language locale. On an English-language iPhone with Region = Brazil, Dart sees en_US, but the numeric keyboard emits , for the decimal. This plugin closes that gap so amount fields format and parse against the correct locale.

What's inside

• AmountInputLocale — canonical enum of numeric formats (1,234.56 / 1.234,56 / 1 234,56 / Indian lakhs / …), with country and Locale resolvers.
• AmountLocalizer — cached intl-backed formatter with sensible banking defaults and a .localizedAmount extension on Object. Also owns the one-shot native bridge via `AmountLocalizer.ensureInitialized`.

Setup

Add the dependency:

dependencies:
  amount_localizer: ^2.0.0

Or:

flutter pub add amount_localizer

Initialize once, early in main() (before runApp):

import 'package:amount_localizer/amount_localizer.dart';

await AmountLocalizer.ensureInitialized();

Idempotent and best-effort — any native failure is swallowed and the plugin falls back to Flutter's language locale. Never throws.

Formatting

100.5.localizedAmount;                       // "100.50" on en_US, "100,50" on pt_BR
AmountLocalizer.format(1234.5);              // "1,234.50" / "1.234,50" / …
AmountLocalizer.tryFormat(json['amount']);   // safe; returns fallback ("—") on failure

Channel

Method channel: com.sri.amount_localizer/region, single method getFormatRegion returning an ISO 3166-1 alpha-2 country code (or null).