SetState and Shared Preferences returning null-CodePudding

I am having trouble identifying as to why setState() is returning null on my shared preferences getString method. I am calling an async function outside of the initState and the constantly printing null when i check the return string of getString on page load. I have checked that setString is saving the correct string to the key. Here is my code:

       void initState() {
        super.initState();
        retrieve();
   
      }

       retrieve() async {
       final prefs = await SharedPreferences.getInstance();
       setState(() {
        name = prefs.getString("displayName");

        print(name);
       });
     }

Here is where I setString(in the register user page):

          try {
            UserCredential result =
                await FirebaseAuth.instance.createUserWithEmailAndPassword(
              email: _emailController.text,
              password: _passwordController.text,
            );
            final user = FirebaseAuth.instance.currentUser;
            final name = _usernameController.text;
            // if (user != null) {
            await user?.updateDisplayName(name);
            Navigator.pushNamed(context, homeRoute);

            print(name);

CodePudding user response：

You should set ,username via shared preference before accessing it.

final prefs = await SharedPreferences.getInstance();

In register page.(where you want to set name via SharedPreference before accessing it)

await prefs.setString('displayName', 'name');

After setting it in registeration you can access like above

name = prefs.getString("displayName");

CodePudding user response：

When SharedPreferences return null value it means you have not set value with your key yet. So firstly set something like this:

final prefs = await SharedPreferences.getInstance().reload();

await prefs.setString('displayName', 'Mark');

then try to call it.