多供应商颤振

Question

Hi I'm trying to get multiproviders to work in my app where I want to be able to share a set of data across all the child widget. in This case I'm reading file on the filesystem to load a set of data (settings).

FileService.readSettings

static Future<Settings> readSettings() async
  {
    try {
      final directory = await getApplicationDocumentsDirectory();
      final file = File('${directory.path}/settings.txt');

      String loadedstring = await file.readAsString();
      Settings settings = (jsonDecode(loadedstring) as Settings);


      return settings; 

    } catch (e) {
      print("Couldn't read file");
    }
  }

_getSetting main.dart file

Future<Settings> _getSettings(BuildContext context) async
  {
    Settings settings = await FileService.readSettings();

    return settings;

  }

My Build method snippet in main.dart

@override
  Widget build(BuildContext context) {

    return ChangeNotifierProvider(
      create: (context) => UserData(),
      child: MultiProvider(
        providers: [
          ChangeNotifierProvider<Settings>(
            create: (context)  => _getSettings(context)
          ),

        ],

I haven't composed the create method properly. I'm getting :

Error: A value of type 'Future' can't be assigned to a variable of type 'Settings'.

I'm not sure how to wait for it to load.

Answer 1

You can use FutureBuilder

  @override
  Widget build(BuildContext context) {
    return FutureBuilder(
      future: _getSettings(context),
      builder: (context, snapshot) {
        return ChangeNotifierProvider(
            create: (context) => UserData(),
            child: MultiProvider(
              providers: [
                ChangeNotifierProvider<Settings>(
                  create: (context)  => snapshot.data
                ),