FutureBuilder conflict with Notifylistener


I have a method like this in my provider file to update a list of items from server :

Future<void> getServerMeals(String userName, String date) async {
    final QueryBuilder<ParseObject> parseQuery =

      ..whereContains('eatenBy', userName)
      ..whereEqualTo('eatenDate', date);

    final ParseResponse apiResponse = await parseQuery.query();

    if (apiResponse.success && apiResponse.results != null) {
      List<dynamic>? apiRes = apiResponse.results;

      List<dynamic> newMeals = apiRes!
          .map((e) => EatenItem(
                id: e['objectId'],
                eatenCal: e['eatenCal'],
                eatenTitle: e['eatenTitle'],
                eatenImageUrl: e['eatenImg'],
                userId: e['objectId'],
      _eatenMeals = newMeals;

and in my main screen I’ve wrapped that list into the FutureBuilder it works fine and return a list:

          height: MediaQuery.of(context).size.height * 0.6,
          margin: EdgeInsets.only(left: 30, right: 30),
          child: FutureBuilder(
            builder: (ctx, snapshot) {
              if (snapshot.connectionState == ConnectionState.waiting) {
                return Center(
                  child: CircularProgressIndicator(),

              return ListView.builder(
                itemCount: mealsList.eatenMeals.length,
                itemBuilder: (ctx, index) =>
            future: Provider.of<EatenMeals>(context)
                .getServerMeals(currentUser.username, now),

but when I’ve added notifylistener() in my method my future builder list stuck on waiting state and won’t update list what’s wrong here


The problem is that you are creating your future in your build method.

That means on every build, you create this future again.

That is a minor nuisance and a bug in your program, until you also add that the future itself triggers a rebuild, which means it will run, trigger a rebuild, the rebuild will wait for a new future, that will run, trigger a rebuild, create yet again a new future… you get it. It’s an endless circle of running a future only to rebuild and run it again.

You have to create your Future outside of the build method. The build method can be triggered many times. Only reference a Future<> type variable in your build method and assign that variable in another method, maybe init or in some setState call when someone clicks a button.

Answered By – nvoigt

Answer Checked By – Katrina (FlutterFixes Volunteer)

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