flutter 다중 언어 처리, json 파일 블랙스크린 불러오는 문제 해결

zh.json : {
"appNam":"    ",
"appVersion": "    "
}
en.json : {  
"appNam":"app name",
"appVersion": "app version"
}

main() {
    runApp(MyApp());
}
class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home:splashPage(),//     
      localizationsDelegates:MyLocalizationsDelegate()
    )
  }
}
//      map
class MyLocalizations {
    static MyLocalizations instance;
    Map globalLocalMap;
}
//        delegate，flutter        load  
class MyLocalizationsDelegate extends LocalizationsDelegate {
  MyLocalizations local = MyLocalizations();
  @override
  Future load(Locale locale) async {
      local.globalLocalMap = json.decode(await rootBundle.loadString(zh.json));
      MyLocalizations.instance = local;
      return SynchronousFuture(MyLocalizations.instance);
  }
}

zh.dart :
var zh = {
"appNam":"    ",
"appVersion": "    "
};
en.dart :
var en = {
"appNam":"app name",
"appVersion": "app version"
}

class MyLocalizationsDelegate extends LocalizationsDelegate {
  MyLocalizations local = MyLocalizations();
  @override
  Future load(Locale locale) async {
      if ("en" == locale.languageCode) {
          local.globalLocalMap = en;//   en，  en.dart       map
      } else if ("zh" == locale.languageCode) {
          local.globalLocalMap = zh;
      } else {
          local.globalLocalMap = zh;//          app   ，     
      }
      MyLocalizations.instance = local;
      return SynchronousFuture(MyLocalizations.instance);
  }
}