Question 78338 in Flutter Question posted in
The official Flutter documentation can be found here.

Unwanted changing of bool and persisting it in storage | Flutter

I am using ListView.builder to create list of Card‘s.

return ListView.builder(
  itemBuilder: (BuildContext context, index) {
     return ListTile(
        title: MyCard(
          cardId: index,
),);},);

In MyCard class i persist boolean shouldRemind in storage by using shared_preferences plugin.

class MyCard extends StatefulWidget {
  const MyCard({
    super.key,
    required this.cardId,
  });

  @override
  State<MyCard> createState() => _CardState();
  final int cardId;
}

class _CardState extends State<MyCard> {
  bool shouldRemind = false;

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

  loadData() async {
    SharedPreferences prefs = await SharedPreferences.getInstance();
    setState(() {
      shouldRemind = prefs.getBool('boolSwitcherKey') ?? false;
    });
  }

  saveBool() async {
    SharedPreferences prefs = await SharedPreferences.getInstance();
    await prefs.setBool('boolSwitcherKey', shouldRemind);
  }

  @override
  Widget build(BuildContext context) {
    return Card(
      color: shouldRemind
          ? const Color.fromARGB(255, 108, 0, 0)
          : const Color.fromRGBO(32, 32, 32, 1),
      child: SizedBox(
          height: 180,
          child: Row(
            mainAxisAlignment: MainAxisAlignment.spaceEvenly,
            children: [
              ElevatedButton.icon(
                  onPressed: () {
                    setState(() {
                      if (shouldRemind == true) {
                        shouldRemind = false;
                      } else {
                        shouldRemind = true;
                      }
                      saveBool();
                    });
                  },
                  icon: const Icon(Icons.alarm),
                  label: const Text("prr prr")),
              Text(shouldRemind.toString())
            ],
          )),
    );
  }
}

Problem is bool shouldRemind, after it is changed by clicking button, it is only one of it, so every single copy of MyCard getting value equal to that what i changed before, i think that is the reason it look like this :
video

I want to have unique bool to every widget, so that after rendering my user another Card value of bool won’t change.

Tags:

2

Answers


  1. 0

    While every card have cardId, you can use it to save and retrieve from SharedPreferences

    '${widget.cardId} boolSwitcherKey'

    loadData() async {
    SharedPreferences prefs = await SharedPreferences.getInstance();
    setState(() {
      shouldRemind = prefs.getBool('${widget.cardId} boolSwitcherKey') ?? false;
    });
  }

  saveBool() async {
    SharedPreferences prefs = await SharedPreferences.getInstance();
    await prefs.setBool('${widget.cardId} boolSwitcherKey', shouldRemind);
  }
    Login or Signup to reply.
  2. 0

    Well with

     await prefs.setBool('boolSwitcherKey', shouldRemind);

    you overwrite the same boolean every single time. You could use the index of the current element or the id of your card to create a unique key.

    await prefs.setBool('boolSwitcherKey' + widget.cardId, shouldRemind);

    and the same to get the bool

    shouldRemind = prefs.getBool('boolSwitcherKey' + widget.cardId) ?? false;
    Login or Signup to reply.
Please signup or login to give your own answer.

Back To Top
Search