Assigning the sharedPreference value to a variable within the build - flutter

Question

I have successfully stored a value as a string in the localStorage as below:
var acceptedCompany = jsonEncode('${item.company!.name!}');
print('storedCompany: $acceptedCompany'); // succesfully prints value as 'abc'
await sharedPref.save('savedCompany', acceptedCompany);
And now I want to read the stored value from another screen and assign it to a variable which I can then bind to my Text() widget. I have successfully accessed the value within my console. However when I try to assign the stored value to a variable, I get an error:
"Instance of Future<dynamic>"
Here is how am getting back the stored value:
class _SideBarState extends State < SideBar > {
SharedPref sharedPref = SharedPref();
var savedCompany;
String key = 'storedCompany';
#override
#override
void didChangeDependencies() {
getCompany();
super.didChangeDependencies();
}
getCompany() async {
savedCompany = await sharedPref.read(key);
print('getComp: $savedCompany'); // this returns the stored value i.e 'abc' but I can't assign this to the Text widget
}
#override
Widget build(BuildContext context) {
var savedCompany2 = getCompany();
print('getComp2: $savedCompany2'.toString()); // generates an error 'Instance of Future<dynamic>'
return Text($savedCompany2);
}
}
My SharedPref Class looks like this:
read(key) async {
final prefs = await SharedPreferences.getInstance();
final value = prefs.getString(key) ? ? 0;
// print('retrievedValue: ' + '$value');
return value;
}
save(key, value) async {
final prefs = await SharedPreferences.getInstance();
// prefs.setString(key, json.encode(value));
prefs.setString(key, value);
// print('savedToken:' + '$key');
}
How can I access the sharedPreference value and assign it to the variable that I can then bind to the Text widget?

Answer 1

To overcome the problem, you can either set the value after the initState or using FutureBuilder.
FutureBuilder:
class SideBar extends StatefulWidget {
const SideBar({Key? key}) : super(key: key);
#override
State<SideBar> createState() => _SideBarState();
}
class _SideBarState extends State<SideBar> {
SharedPref sharedPref = SharedPref();
String key = 'storedCompany';
Future<String> getCompany() async {
return await sharedPref.read(key);
}
#override
Widget build(BuildContext context) {
return FutureBuilder<String>(
future: getCompany(),
builder: (BuildContext context, AsyncSnapshot<String> snapshot) {
if (snapshot.hasData) {
return Text('Result: ${snapshot.data}');
} else if (snapshot.hasError) {
return Text('Error: ${snapshot.error}');
} else {
return Center(child: CircularProgressIndicator());
}
},
);
}
}
After initState():
class SideBar extends StatefulWidget {
const SideBar({Key? key}) : super(key: key);
#override
State<SideBar> createState() => _SideBarState();
}
class _SideBarState extends State<SideBar> {
SharedPref sharedPref = SharedPref();
String key = 'storedCompany';
String? _companyName;
Future<void> getCompany() async {
var name = await sharedPref.read(key);
setState(() {
_companyName = name;
});
}
#override
void initState() {
super.initState();
getCompany();
}
#override
Widget build(BuildContext context) {
if(_companyName == null) return Center(child:CircularProgressIndicator());
return Text(_companyName!);
}
}