SharedPreferences in Flutter not persisting?

Question

I'm trying to implement a "Remember Me" functionality by using SharedPreferences. Unfortunately, no matter what I do, it doesn't seem like the login details are persisting. I'm using SharedPreferences on my Sign In screen as below by invoking it in the initState method (through to my GetX controller):

  final SignInController controller = Get.put(SignInController());
 
  @override
  void initState() {
    // TODO: implement initState
    controller.loadRememberMeDetails();
    super.initState();
  }

...

Row(
 children: [
                                        SizedBox(
                                          height: 24.0,
                                          width: 24.0,
                                          child: GetBuilder<SignInController>(
                                            builder: (s) => Checkbox(
                                              value: s.isChecked,
                                              onChanged: s.handleRememberMe,
                                            ),
                                          ),
                                        ),
                                        SizedBox(width: 5.0),
                                        Material(
                                            color: Colors.transparent,
                                            child: InkWell(
                                              onTap: () {
                                                controller.handleRememberMe(
                                                    !controller.isChecked);
                                              },
                                              child: Text(
                                                "Remember Me",
                                                style: TextStyle(
                                                    color: Colors.black,
                                                    fontSize: 15),
                                              ),
                                            ))
                                      ],
                                    ),

I invoke the following to save it:

  void handleRememberMe(bool? value) async {
    SharedPreferences prefs = await SharedPreferences.getInstance();
    await prefs.setBool("remember_me", value!);
    await prefs.setString('email', emailController.text);
    await prefs.setString('password', passwordController.text);

    print("Remember me: ${emailController.text} ${passwordController.text}");

    isChecked = value!;
    update();
  }

initState() invokes the following method on initialisation:

 void loadRememberMeDetails() async {
    try {
      SharedPreferences prefs = await SharedPreferences.getInstance();
      var email = prefs.getString("email") ?? "";
      var password = prefs.getString("password") ?? "";
      var rememberMe = prefs.getBool("remember_me") ?? false;

      if (rememberMe) {
        isChecked = true;
        emailController.text = email;
        passwordController.text = password;
        update();
      }
    } catch (e) {
      print(e);
    }
  }

However, email, etc local variables show null.

Any ideas on how to fix?

Answer 1

You can use GetStorage to achieve that, is easier to use, adapting to your code, it can be like this:

1. In your main.dart:

main() async {
  await GetStorage.init();
  runApp(App());
}

2. Then call your storage space in initState:

  @override
  void initState() {
    // TODO: implement initState
    final box = GetStorage();
    controller.loadRememberMeDetails();
    super.initState();
  }

3. And in your functions:

 void handleRememberMe(bool? value){
   box.write('remember_me', value!.toString());
   box.write('email', emailController.text);
   box.write('password', emailController.text);
   print("Remember me: ${emailController.text} ${passwordController.text}");
   isChecked = value!;
   update();
 }


void loadRememberMeDetails(){
   try {
     
     var email = box.read("email")??"";
     var password = box.read("password")??"";
     var rememberMe = box.read("remember_me") == "true" ? true : false;

     if (rememberMe) {
       isChecked = true;
       emailController.text = email;
       passwordController.text = password;
       update();
     }
   } catch (e) {
     print(e);
   }
 }