Display data from sqlite to simpledialog in flutter

I want to display data from sqlite to SimpleDialog widget

showDialog(
  context: context,
  barrierDismissible: true,
    builder: (BuildContext context) {
      return SimpleDialog(
        title: const Text('Select Category '),
        children: <Widget>[
          dbHelper.getCategories().then((val) {
            for (var item in val) {
              SimpleDialogOption(
                onPressed: () {
                  Navigator.pop(context);
                },
                child: const Text('Food'),
              );
            }
          }),
      ],
    );
});

While doing this I am getting the below error:

type 'Future' is not a subtype of type 'Widget'

You are trying to add SimpleDialogOption widgets to children, but you need to await for the future to complete before adding them.

type 'Future' is not a subtype of type 'Widget'

This error should give you a hint: it expects widgets, and you are giving it a future (dbHelper.getCategories().then((val) returns a Future).

What works is awaiting for your categories before displaying the dialog. For this you can use a FutureBuilder:

FutureBuilder(
  future: dbHelper.getCategories(),
  builder: (BuildContext context, AsyncSnapshot snapshot) {
    if (snapshot.hasData) {
      showDialog(
        context: context,
        barrierDismissible: true,
        builder: (BuildContext context) {
          return SimpleDialog(
            title: const Text('Select Category '),
            children: [
              for (var item in snapshot.data) {
                SimpleDialogOption(
                  onPressed: () { Navigator.pop(context); },
                  child: const Text('Food'),
                );
              }
            }