Flutter Framework localizations
This package contains the localizations used by the Flutter framework itself.
See the localization README for more detailed information about the localizations themselves.
Adding a new string to localizations
If you (someone contributing to the Flutter framework) want to add a new
string to the MaterialLocalizations
, WidgetsLocalizations
or the
CupertinoLocalizations
objects (e.g. because you've added a new widget
and it has a tooltip), follow these steps (these instructions are for
MaterialLocalizations
, but apply equally to CupertinoLocalizations
and WidgetsLocalizations
, with appropriate name substitutions):
-
String get showMenuTooltip;
to the localizations class
MaterialLocalizations
, inpackages/flutter/lib/src/material/material_localizations.dart
;String aboutListTileTitle(String applicationName);
to the same localization class.
-
Implement a default return value in
DefaultMaterialLocalizations
in the same file as in step 1.@override String get showMenuTooltip => 'Show menu';
@override String aboutListTileTitle(String applicationName) => 'About $applicationName';
For messages with parameters, do also add the function to
GlobalMaterialLocalizations
inpackages/flutter_localizations/lib/src/material_localizations.dart
, and add a raw getter as demonstrated below:/// The raw version of [aboutListTileTitle], with `$applicationName` verbatim /// in the string. @protected String get aboutListTileTitleRaw; @override String aboutListTileTitle(String applicationName) { final String text = aboutListTileTitleRaw; return text.replaceFirst(r'$applicationName', applicationName); }
-
Add a test to
test/material/localizations_test.dart
that verifies that this new value is implemented. -
Update the
flutter_localizations
package. To add a new string to theflutter_localizations
package, you must first add it to the English translations (lib/src/l10n/material_en.arb
), including a description."showMenuTooltip": "Show menu", "@showMenuTooltip": { "description": "The tooltip for the button that shows a popup menu." },
"aboutListTileTitle": "About $applicationName", "@aboutListTileTitle": { "description": "The default title for the drawer item that shows an about page for the application. The value of $applicationName is the name of the application, like GMail or Chrome.", "parameters": "applicationName" },
Then you need to add new entries for the string to all of the other language locale files by running:
dart dev/tools/localization/bin/gen_missing_localizations.dart
Which will copy the English strings into the other locales as placeholders until they can be translated.
Finally you need to re-generate lib/src/l10n/localizations.dart by running:
dart dev/tools/localization/bin/gen_localizations.dart --overwrite
If you got an error when running this command, this issue might be helpful.
TL;DR: If you got the same type of errors as discussed in the issue, run this instead:
dart dev/tools/localization/bin/gen_localizations.dart --overwrite --remove-undefined
There is a localization README file with further information in the
lib/src/l10n/
directory. -
If you are a Google employee, you should then also follow the instructions at
go/flutter-l10n
. If you're not, don't worry about it.
Updating an existing string
If you or someone contributing to the Flutter framework wants to modify an existing string in the MaterialLocalizations objects, follow these steps:
-
Modify the default value of the relevant getter(s) in
DefaultMaterialLocalizations
below. -
Update the
flutter_localizations
package. Modify the out-of-date English strings inlib/src/l10n/material_en.arb
.You also need to re-generate
lib/src/l10n/localizations.dart
by running:dart dev/tools/localization/bin/gen_localizations.dart --overwrite
This script may result in your updated getters being created in newer locales and set to the old value of the strings. This is to be expected. Leave them as they were generated, and they will be picked up for translation.
There is a localization README file with further information in the
lib/src/l10n/
directory. -
If you are a Google employee, you should then also follow the instructions at
go/flutter-l10n
. If you're not, don't worry about it.