Flutter Q & A


How do you localize strings in a Flutter application?

Localizing strings in a Flutter application is crucial for creating multilingual and user-friendly apps. Flutter provides a straightforward approach to achieve this through the Flutter Internationalization (i18n) package. Here’s a detailed explanation of how to localize strings in Flutter:


To begin, create a ‘lib/l10n’ directory in your Flutter project to store localization-related files. Inside this directory, add a file named ‘app_localizations.dart’ that defines the ‘AppLocalizations’ class. This class extends ‘LocalizationsDelegate’ and contains methods for loading the correct localization file based on the user’s locale.


Next, create JSON files for each supported language, such as ‘en.json’ for English and ‘es.json’ for Spanish. These files will reside in the ‘lib/l10n’ directory and contain key-value pairs, where the keys represent the original English strings and the values are their translated counterparts.


For example, in ‘en.json’:

  "greeting": "Hello, World!",
  "welcome": "Welcome to my app!"
And in 'es.json':
  "greeting": "¡Hola, Mundo!",
  "welcome": "Bienvenido a mi aplicación"

Utilize the ‘intl’ package to format dynamic content within localized strings, such as date and number formatting. Import the ‘flutter_localizations’ package in your app’s main file and configure it to use your ‘AppLocalizations’ delegate.


Finally, use the ‘AppLocalizations’ class to access localized strings throughout your app. For instance:




This approach ensures that your Flutter app adapts seamlessly to different languages, providing a personalized experience for users worldwide. Regularly update the localization files as your app evolves, maintaining a commitment to inclusivity and accessibility.

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Full Stack Systems Analyst with a strong focus on Flutter development. Over 5 years of expertise in Flutter, creating mobile applications with a user-centric approach.