How to Save List in SharedPreferences in Flutter-CodePudding

Hello all at first I want to mention that I've tried a lot of solutions here but it didn't work for me.

I bring the list from the database through the following code:

 var listCat = [];
  Future getdata() async {
    apiURL = '***************.php';
    var response = await http.post(Uri.parse(apiURL));
    var responsebody = jsonDecode(response.body);
    if (responsebody.length >0){
      for (int i = 0; i < responsebody.length; i  ) {
        listCat.add(responsebody[i]['name']  ':'   responsebody[i]['image'].toString());
      }
      return responsebody;
    }else{
  

    }
  }

As is obvious in the code above I am trying to get the name and image and this is not a problem right now I want to store this listCat in SharedPreferences until I recall it from all pages of the app

I have the following class to save SharedPreferences:

class APIPreferences {
  static SharedPreferences ? _preferences;
  static const _keyMuinCat = 'MuinCat';



  static Future init() async => _preferences = await SharedPreferences.getInstance();


  static Future setMuinCat(String MuinCat) async => await _preferences!.setString(_keyMuinCat, MuinCat);



  static String? getMuinCat() => _preferences!.getString(_keyMuinCat);



}

Then I save what I need to save by the following line:

APIPreferences.setMuinCat(listCat.toString());

Then I can bring pre-stored data from any location where I need it through the following code:

CatList = APIPreferences.getMuinCat() ?? '';

I tried to do the following thing now to save the list in the first code above:

var listCat = [];
  Future getdata() async {
    apiURL = '***************.php';
    var response = await http.post(Uri.parse(apiURL));

    var responsebody = jsonDecode(response.body);

    if (responsebody.length >0){

      for (int i = 0; i < responsebody.length; i  ) {
        listCat.add(responsebody[i]['name']  ':'   responsebody[i]['image'].toString());
        APIPreferences.setMuinCat(listCat.toString());

      }

      return responsebody;
    }else{


    }
  }

But it didn't work. I don't really know how to deal with it.

How can I save it and then bring it to use with ListView.

CodePudding user response：

To save the list in shared preferences you need to pass as jsonEncode(yourList data) and when you will fecth the shared list you will again jsonDecode(your list)

await prefs.setString('YOUR KEY', json.encode(YOURMAP()));

CodePudding user response：

instead of:

_preferences!.setString(_keyMuinCat, "some string");

use:

_preferences!.setStringList(_keyMuinCat, ["some", "strings", "in", "list"]);

So in your code, the setMuinCat method needs to be:

static Future setMuinCat(List<String> muinCat) async => await _preferences!.setStringList(_keyMuinCat, muinCat);

and then you call it like this:

APIPreferences.setMuinCat(listCat);