Generates a localizations delegate from an online Google Sheet file.

Add the following to your pubspec.yaml:

dependencies:
  flutter_sheet_localization: ^1.0.0

dev_dependencies:
  flutter_sheet_localization_generator: ^1.0.0
  build_runner: ^1.3.1

Create a sheet with your translations (following the bellow format, an example sheet is available here) :

Make sure that your sheet is shared :

Extract from the link the DOCID and SHEETID values : https://docs.google.com/spreadsheets/d/<DOCID>/edit#gid=<SHEETID>) :

Declare the following AppLocalizationsDelegate class with the SheetLocalization annotation pointing to your sheet in a lib/localization.dart file :

import 'package:flutter/widgets.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter_sheet_localization/flutter_sheet_localization.dart';

part 'localizations.g.dart';

@SheetLocalization("DOCID", "SHEETID") // <- See 1. to get DOCID and SHEETID
class AppLocalizationsDelegate extends LocalizationsDelegate<AppLocalizations> {
  const AppLocalizationsDelegate();

  @override
  bool isSupported(Locale locale) =>
      AppLocalizations.languages.containsKey(locale);
  @override
  Future<AppLocalizations> load(Locale locale) =>
      SynchronousFuture<AppLocalizations>(AppLocalizations(locale));
  @override
  bool shouldReload(AppLocalizationsDelegate old) => false;
}

Run the following command to generate a lib/localization.g.dart file :

flutter packages pub run build_runner build

Update your Flutter app with your newly created delegate :

MaterialApp(
    locale: AppLocalizations.languages.keys.first, // <- Current locale
    localizationsDelegates: [
    const AppLocalizationsDelegate(), // <- Your custom delegate
    GlobalMaterialLocalizations.delegate,
    GlobalWidgetsLocalizations.delegate,
    ],
    supportedLocales:
        AppLocalizations.languages.keys.toList(), // <- Supported locales
    // ...
);

final labels = AppLocalizations.of(context);
print(labels.dates.month.february);
print(labels.templated.hello(firstName: "World"));
print(labels.templated.contact(Gender.male, lastName: "John"));

You can see an example sheet here.

The file should have :

• A first header row
  • Column 0 : "Key"
  • then each supported language code ("en", "fr", ...)
• Following rows for labels
  • Column 0 : the label key (can be a hierarchy, separated by dots)
  • then each translation based on language code of the column

It is pretty common to have variants of a label based on a condition (for example: Genders, Plurals, ...).

Simply duplicate your entries and end them with (<ConditionName>.<ConditionCase).

Example :

Key	fr	en
example.man(Gender.male)	homme	man
example.man(Gender.female)	femme	woman

See example for more details.

The conditionals can be used the same way for plurals :

Example :

Key	fr	en
example.man(Plural.zero)	hommes	man
example.man(Plural.one)	homme	man
example.man(Plural.multiple)	hommes	men

From your Dart code, you can then define a function :

Plural plural(int count) {
  if (count == 0) return Plural.zero;
  if (count == 1) return Plural.one;
  return Plural.multiple;
}

See example for more details.

You can insert a {{KEY}} template into a translation value to have dynamic labels.

A Dart function will be generated to be used from your code.

/// Sheet
values.hello, "Hello {{first_name}}!"

/// Code
print(labels.values.hello(firstName: "World"));

See example for more details.

I find the Flutter internationalization tools not really easy to use, and I wanted a simple tool for sharing translations. Most solutions also use string based keys, and I wanted to generate pure dart code to improve performance.