How do I use sharedPreferences with booleans?

Question

I am currently learning sharedPreferences and trying to set and get values to check if a button has been clicked or not.

This is my class for sharedPreferences

class UserSimplePrefences {
  static SharedPreferences? _preferences;
  static const _keyButton = 'buttonStatus';

  static Future init() async {
    _preferences = await SharedPreferences.getInstance();
  }

  static Future setButtonStatus(bool btnStatus) async {
    await _preferences?.setBool(_keyButton, btnStatus);
  }

  static bool? getButtonStatus() {
    return _preferences?.getBool(_keyButton);
  }
}

here in my main.dart I have a button.

bool? onLineStatus;
//
void initState() {
    super.initState();
    WidgetsBinding.instance?.addObserver(this);
    onLineStatus = UserSimplePrefences.getButtonStatus() !;
    displayToastMessage(onLineStatus.toString(), context);
}

//
@override
  Widget build(BuildContext context) {
//
RaisedButton(

    onPressed: () async {
        if (UserOnline! =true) {
        UserOnline = true;
        await UserSimplePrefences.setButtonStatus(true);
        displayToastMessage("You are Online now", context);
    } else {
        UserOnline =false;
        await UserSimplePrefences.setButtonStatus(false);
        displayToastMessage("You are Offline now", context);

    }}
),
}

UserOnline is to toggle the button, works fine without SharedPreferences. In more simple language, when I hit the button i.e Online and close the app and reopen the app sometime later I want the init statement to be called with the toast message as true and similarly when I click offline I want the init statement to call the toast false.

Issue: My toast message is always true. `

Answer 1

add setState to your onPressed

onPressed: () async {
        if (UserOnline! =true) {
        UserOnline = true;
        await UserSimplePrefences.setButtonStatus(true);
        displayToastMessage("You are Online now", context);
        setState(() {});
    } else {
        UserOnline =false;
        await UserSimplePrefences.setButtonStatus(false);
        displayToastMessage("You are Offline now", context);
        setState(() {});
    }}