shared preference is deleted when application is closed

Question

i am building a log in screen using flutter and save user data in shared preference if it is right then i tested the saved data in the second screen and it has been already saved when the app is closed and open again i check the shared pref but it becomes null that's my saveData & getData Functions

String namePref,phonePref, typePref,statePref;
Future saveDataPref(String name,String phone, String type, String state )async{
  SharedPreferences pref = await SharedPreferences.getInstance();
  pref.setString('phone', phone);
  pref.setString('name', name);
  pref.setString('type', type);
  pref.setString('state', state);
  pref.commit();
  print('pref stored');
  print('${pref.getString('phone')}');
}

Future getDataPref() async{
  SharedPreferences pref = await SharedPreferences.getInstance();
  phonePref = pref.getString('phone');
  namePref = pref.getString('name');
  typePref = pref.getString('type');
  statePref = pref.getString('state');
}

i should mention two things "commit" function is deprecated the second one is that the code was working with the deprecated commit but it is not now i removed all the changes i have done but it still not working on my device and other devices and don't know understand why ! if there is no solution, is there any alternative to shared preference in flutter ? that's where i use saveDataPref()

Future login(BuildContext context) async {
  String password = passwordController.text;
  String phone = phoneController.text;
  print("entered login function");
  //check if the user is registered
  Map<String, User> users = new Map<String, User>();
  users = await getUserDataFromFireStore();
  if (await userCheck(phone)) {
    // user is registered check if it is the right password
    if (users[phone].password == password) {
      // check if the user have an order

saveDataPref( users[phone].phone, users[phone].name, "user", users[phone].ordered);

      if (users[phone].ordered == "true") {
        Navigator.push(
            context, MaterialPageRoute(builder: (context) => OrderBinding()));
        return;
      } else {
        Navigator.push(
            context,
            MaterialPageRoute(
                builder: (context) => UserApp(
                      userName: users[phone].name,
                      userPhone: users[phone].phone,
                    )));
        return;
      }
    } else {
      ShowDialogue(
          "تم إدخال كلمة السر بشكل خاطئ من فضلك تأكد من كلمة السر", context);
    }
  }

  Map<String, Driver> drivers = new Map<String, Driver>();
  drivers = await getDriverDataFromFireStore();
  if (await DriverCheck(phone)) {
    // user is registered check if it is the right password
    if (drivers[phone].password == password) {
      //check if driver account is activated
      if (drivers[phone].activation == "true") {
        saveDataPref(drivers[phone].phone, drivers[phone].name, "driver",
            drivers[phone].activation);
        Navigator.push(
            context, MaterialPageRoute(builder: (context) => DriverApp()));
      } else {
        ShowDialogue(
            "لم يتم تفعيل حسابكم بعد يرجى الانتظار وسيتم التواصل معكم قريباً",
            context);
      }
    } else {
      ShowDialogue(
          "تم إدخال كلمة السر بشكل خاطئ من فضلك تأكد من كلمة السر", context);
    }
  } else {
    ShowDialogue(
        "لم يتم تسجيل هذا المستخدم من فضلك قم بانشاء حساب اولا", context);
  }
}

here i check if the login data is right i tested the function and i works it opens saveDataPref() and i use retrieve data from another screen and it works but when closing the app and open it again i use getDataPref() but the retrieved data is null here where i use getDataPref() to check if the user is already register so go tu UserApp screen and if not open home screen

checkSigned() {
  getDataPref();
  print("${phonePref}");
  print("${namePref}");
  if (phonePref != null) {
    print("${phonePref}");

    if (phonePref != "") {
      print("${phonePref}");

      return new UserApp(
        userName: namePref,
        userPhone: phonePref,
      );
    } else {
      return new MyHomePage();
    }
  } else {
    return new MyHomePage();
  }
}

void main() {
  runApp(new MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: 'Generated App',
      theme: new ThemeData(
        primarySwatch: Colors.lightGreen,
        primaryColor: const Color(0xFF8BC34A),
        accentColor: const Color(0xFF8BC34A),
        canvasColor: const Color(0xFFEEEEEE),
      ),
      home: checkSigned(),
    );
  }
}

I don't use commit(). Just setString() and it works great. Are you calling pref.clear() anywhere in your app? — Sebastian, Sep 13 '18 at 20:58
i deleted it but still not working i used remove in another screen and deleted the function and still not working — Ahmed El Sayed, Sep 13 '18 at 21:29
i updated the question with the places i use saveDataPref() and getDataPref() , it is a global method in the main class file — Ahmed El Sayed, Sep 14 '18 at 09:48
i think the value is stored in cache like mentioned here: https://stackoverflow.com/questions/51215064/flutter-access-stored-sharedpreference-value-from-other-pages/ how can i save it to device memory not to the cache? — Ahmed El Sayed, Sep 15 '18 at 11:04

score 3 · Answer 1 · answered Sep 24 '20 at 02:44

3

I came to the conclusion that i was using prefs.clear() in my app somewhere due to which the data was getting lost. Make sure there is no prefs.clear() written in any of your activity.

answered Sep 24 '20 at 02:44

Abdullah Arshad

156
2
6

score 1 · Answer 2 · answered Aug 05 '21 at 06:29

Make sure you are not calling pref.clear(); anywhere in your code.

loadUserId() async {
SharedPreferences pref = await SharedPreferences.getInstance();
setState(() {
  userId = pref.getString("userId");
});}

And finaly call the above function inside your initState() like this:

@override
    void initState() {
     super.initState();
      loadUserId();
 }

score 0 · Accepted Answer · edited Nov 27 '20 at 11:36

0

I found the solution in here:

Flutter: Shared Preferences null on Startup

And note that, shared preference will not work if you called it outside the main class as I did before. You should call it inside initState(). This works:

@override
  void initState() {
    super.initState();
    readFile('phone');
    SharedPreferences.getInstance().then((SharedPreferences sp) {
      sharedPreferences = sp;
      ph = sp.getString('phone');
      setState(() {});
    });
  }

edited Nov 27 '20 at 11:36

Akif

7,098
7
27
53

answered Sep 16 '18 at 17:09

Ahmed El Sayed

499
1
8
17

1

It still not working for me : [shared preferecences do not persist](https://stackoverflow.com/questions/54523760/flutter-sharedpreference-do-not-persist). – Jérémy Feb 05 '19 at 22:15

score 0 · Answer 4 · answered Jun 07 '23 at 07:39

0

Removed the Line

SharedPreferences.setMockInitialValues({});

code working

answered Jun 07 '23 at 07:39

Arjun Singh

57
4

shared preference is deleted when application is closed

4 Answers4

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