Adding your own localized messages

Once the flutter_localizations package is added, use the
following instructions to add localized text to your application.

Add the intl package as a dependency,
using the version pinned by flutter_localizations with any:

    
$ flutter pub add intl:any

Then in the pubspec.yaml file, enable the generate flag. 
This is added to the section of the pubspec that is specific to Flutter, 
and usually comes later in the pubspec file.

    
# The following section is specific to Flutter.
flutter:
  generate: true # Add this line

Add a new yaml file to the root directory of the Flutter project 
called l10n.yaml with the following content:

    
arb-dir: lib/l10n
template-arb-file: app_en.arb
output-localization-file: app_localizations.dart