Flutter 常量文件与提供者 package

Question

I'm having trouble figuring out the best way to set up some constants (mainly strings). Currently I'm using a constants.dart file that just has the const variables defined in there and import it whenever it's needed. No class or anything, just a blank dart file. This works, however, I recently implemented localization using the Flutter Intl plugin in Android Studio. I got everything to work and can do something like this S.of(context).settings and it gets the translation from the correct file. My problem comes with some constant list of strings I have in my constants.dart file. I use them in many places for option selects. They look like this:

const playType = [
  'RP/Story Focused',
  'Battle/Combat Focused',
  'Puzzles and Challenges',
  'Exploration/Travel',
];
const length = [
  'One Shot',
  '2-5 Sessions',
  '5-10 Sessions',
  'On-going Campaign',
];

I cant change the the strings to the Intl reference because there is not context to be passed. Not sure how to set up a class that is loaded but not sure how to set that up and use the Provider package to serve it up.

EDIT: heres the Constants file. Calling this with the provider is fine. The issue comes when I need to use the localization on the strings in the lists

import 'package:scryer/generated/l10n.dart';

class Constants {
  Constants._();
  static final instance = Constants._();

  static List<String> playType = [
    S.of(context).rpstoryFocused,//need a reference to a context
    'Battle/Combat Focused',
    'Puzzles and Challenges',
    'Exploration/Travel',
  ];
  static const length = [
    'One Shot',
    '2-5 Sessions',
    '5-10 Sessions',
    'On-going Campaign',
  ];
}

Heres how I call the constants on the actual page. Its a button that on press goes to a new screen that is either a multiselect checkbox list or single select radiobutton list. I pass the constants as an argument for the list

MaterialPageRoute(builder: (context) {
  return MultiSelectScreen(
    args: MultiSelectArguments(
      label: S.of(context).selectPreferredPlayStyle,
      options: playType, //this is the constants list reference
      selections:
        profile.playType,
    ),
  );
})

The easy solution is to not use a constant and just create the lists in these spots, only used like twice i think, but better practice is to pull it out since its being used multiple times

Answer 1

you can try.

class Constants {
   final BuildContext context;
   Constants(@required this.context);
 //  static final instance = Constants._();     // to make class a singleton

static  const playType = [
    'RP/Story Focused',
    'Battle/Combat Focused',
    'Puzzles and Challenges',
    'Exploration/Travel',
  ];
static const length = [
    'One Shot',
    '2-5 Sessions',
    '5-10 Sessions',
    'On-going Campaign',
 ];

}

Then, at the root of your project you should provide this class like;

void main() {

/** WidgetsFlutterBinding.ensureInitialized() is required in Flutter v1.9.4+ before using any plugins if the code is executed before runApp. */
  WidgetsFlutterBinding.ensureInitialized();

     runApp( Provider( 
       create: (context) => Constants(context),
       child: MyApp(),
       ),
   );

}

You will be able to access these constants in any BuildContext anywhere down the widget tree as follows;

final Contants constants = Provider<Constants>.of(context);

you get the length constant like; constants.length