How to save a list of objects locally in Flutter? - flutter

Question

I have a page from which I need to save data locally as a list. To save, I use SharedPrefs, there, through the model, I save the data as a list. But I ran into a problem that I can not specify the format for receiving data List, tell me how can I save data as a list and receive data as a list?
class RecentlySearchedModel {
String name;
String address;
RecentlySearchedModel({
required this.name,
required this.address,
});
factory RecentlySearchedModel.fromJson(Map<String, dynamic> json) {
return RecentlySearchedModel(
name: json['name'] as String,
address: json['address'] as String,
);
}
Map<String, dynamic> toJson() {
return {
'name': name,
'address': address,
};
}
}
repository
#override
Future setResentlySearched({required List<RecentlySearchedModel> searchedList}) async {
final SharedPrefs prefs = SharedPrefs();
await prefs.setString(_name, jsonEncode( ))
}
#override
Future<List<RecentlySearchedModel>?> getResentlySearched() async {
final SharedPrefs prefs = SharedPrefs();
final data = await prefs.getString(_name);
if (data == null) return null;
return List<RecentlySearchedModel>.fromJson(
jsonDecode(data),
);
}

Answer 1

update your repository like this.
#override
Future setResentlySearched({required List<RecentlySearchedModel> searchedList}) async {
final SharedPrefs prefs = SharedPrefs();
await prefs.setString(_name, jsonEncode(searchedList.toJson());
}
#override
Future<List<RecentlySearchedModel>?> getResentlySearched() async {
final SharedPrefs prefs = SharedPrefs();
final data = await prefs.getString(_name);
if (data == null) return null;
Iterable l = json.decode(data);
List<RecentlySearchedModel> posts = List<RecentlySearchedModel>.from(l.map((model)=> RecentlySearchedModel.fromJson(model)));
return posts;
}

Answer 2

i havent try to complie, but its should be like this
Future setResentlySearched({required List<RecentlySearchedModel> searchedList}) async {
List<Map<String,dynamic>> listItem = searchedList.map((e)=> e.toJson()).toList();
String jsonString = jsonEncode(listItem);
final SharedPrefs prefs = SharedPrefs();
await prefs.setString(_name, jsonString)
}
and get it back
Future<List<RecentlySearchedModel>?> getResentlySearched() async {
final SharedPrefs prefs = SharedPrefs();
final data = await prefs.getString(_name);
if (data == null) return null;
return (jsonDecode(data) as List).map((e)=> RecentlySearchedModel.fromJson(e)).toList();
}