Listview not showing on startup but shows after rebuilding/refreshing - Flutter - flutter

Question

I need some help please. On startup, everything loads except the listview. When I do anything on the page the listview appears. Feels like a refresh/rebuild issue. How do I tell it to refresh the listview? I don't know where to maybe use setState (doesn't work in Scaffold)
Widget build(BuildContext context) {
return Scaffold(
appBar: _buildBar(context),
body: HouseLayout(),
);}
class HouseLayout extends StatefulWidget {
#override
HouseLayoutState createState() {
return HouseLayoutState();
}
}
class HouseLayoutState extends State<HouseLayout> with TickerProviderStateMixin {
#override
Widget build(BuildContext context) {
int y = 0;
return Scaffold(
appBar: AppBar(
centerTitle: true,
title: Text(taal.HuisTitle,
style: TextStyle(
fontWeight: FontWeight.normal,
color: Colors.white,
fontSize: 28,
)),
backgroundColor: Color.fromRGBO(61, 147, 243, 1.0)),
body: Stack(alignment: Alignment.bottomLeft, children: [
Column(children: [
Expanded(
flex: 10,
child: ListView.builder(
shrinkWrap: true,
itemBuilder: (context, indexA) {
var kasNaam = kaste[indexA];
return Padding(
padding: EdgeInsets.all(0.0),
child: Column(children: <Widget>[
Card(
color: Color.fromRGBO(96, 166, 243, 1.0),
child: Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
Padding(
padding: const EdgeInsets.all(8.0),
child: Text(
'$kasNaam',
style: TextStyle(
fontWeight: FontWeight.normal,
color: Colors.white,
fontSize: 20,
),
),
),
Container(
child: Row(
children: [
IconButton(
icon: Icon(Icons.edit,
color: Colors.white),
onPressed: () {
setState(() {
_editKasDialog(indexA);
});
}),
IconButton(
icon: Icon(Icons.delete,
color: Colors.white),
onPressed: () {
setState(() {
for (int i = 0;
i < kruideniers.length;
i++) {
if (kruideniers[i].kas ==
kaste[indexA]) {
y++;
}
}
if (y != 0) {
_deleteNotPossibleDialog(y);
}
if (y == 0) {
_deleteKasConfirmDialog(indexA);
}
});
}),
],
),
),
]),
),
_isSearching
? _buildSearchList(context, kasNaam)
: _bouKruideniersLys(context, kasNaam),
]),
);
},
itemCount: kaste.length,
)),
Container(height: 40),
]),
Container(color: Color.fromRGBO(61, 147, 243, 1.0), height: 40),
Positioned(
bottom: 0,
right: 0,
child: Stack(children: [
Container(width: 300, height: 350),
Positioned(...),
Positioned(...),
Positioned(...),
Positioned(...),
Positioned(...),
Container(width: 5, height: 5),
Padding(
padding: const EdgeInsets.all(8.0),
child: FloatingActionButton(
elevation: 5,
shape: CircleBorder(),
backgroundColor: Color.fromRGBO(16, 124, 243, 1.0),
child: SizedBox(
width: 56,
height: 56,
child: Icon(Icons.shopping_cart,
size: 35, color: Colors.white)),
splashColor: Colors.yellow,
onPressed: () {
setState(() {
Navigator.pushNamed(context, '/shop');
});
},
heroTag: null)),
],
),
),
]),
)
]));
}
Any help will be great! Thanks
I read kaste list from a txt file:
List<String> kaste = [];
void readFileH() async {
final fileH = await findFileH();
List<String> contents = await fileH.readAsLines();
String kas;
for (int i = 0; i < contents.length; i++) {
kas = contents[i].substring(0, contents[i].indexOf("#"));
contents[i] = contents[i].replaceRange(0, contents[i].indexOf("#") + 1, "");
kaste.add(kas);
}
kaste.sort();
}

Answer 1

Hi the problem is that the data is null when flutter render the ListView because the data isn't loaded, you need to use a wrap your ListView into a future builder, while the data is loading you can put a image or a circular progress indicator, when the data is loaded you render the elements into a ListView