How to solve SharedPreferences not working in flutter

user_11004139 0
Viewed 7637

I am using SharedPreferences to save the response from API. I want to use when my apps is offline or switch to another tab, the data will not reload again. But it not working. It only working when I online. But if I online I switch the page the data will reload again. If I offline the data will not come out.

flutter
3 Answers

Ruturn the data in finally : 

Future<PagesData> sendPagesDataRequest(int page) async {
  SharedPreferences prefs = await SharedPreferences.getInstance();

  try {
    // your codes ...
  } finally {
    String myDataValue = prefs.getString('myData');
    return pagesDataFromJson(myDataValue);
  }
}
user_127854900

From the code, I see that when you are online you get the data and it gets parsed, but when you are offline and you are doing all the stuff in the try-catch block, so when you go offline there is socket Exception that occurs in a catch block that you have not handled.

SharedPreferences prefs = await SharedPreferences.getInstance();
        String myDataValue = prefs.getString('myData');
        final project = pagesDataFromJson(myDataValue);

if you call this in the catch you might be able to get the data when you are offline.

But this is just a fix check this link which will tell you if internet is there or no : https://pub.dev/packages/data_connection_checker

or youcan refer this video :

https://www.youtube.com/watch?v=u_Xyqo6lhFE

So it would not load the data from the prefrences because when you get the exception it directly goes to the catch without leaving the below code.

user_120000530

Fetch data from the API

Future<String> fetchPagesData(int page) {
  String url = Uri.encodeFull("https://API_URL?page=$page");
  return http.get(url).body;
}

Set SharedPreferences data

Future<String> setPagesData(int page, String value) async {
  SharedPreferences prefs = await SharedPreferences.getInstance();
  prefs.setString('myData$page', value);
}

Get SharedPreferences data

Future<PagesData> getPagesData(int page) async {
  SharedPreferences prefs = await SharedPreferences.getInstance();
  return prefs.getString('myData$page');
}

Catch while offline

Future<PagesData> sendPagesDataRequest(int page) async {
  try {
    fetchPagesData(page).then((value) => setPagesData(page, value));
//   } on SocketException {
// no network connection   
  } catch (e) {}

  return getPagesData(page);
}
user_127854900
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