Can not read properties of null, ListView.Builder - flutter

Question

I have this problem in flutter, I want to fetch API with listview builder but they show this error after 2 seconds i got my data
//listviewBuilder
return Container(
height: 380,
child: ListView.builder(
padding: EdgeInsets.symmetric(vertical: 8.0),
scrollDirection: Axis.horizontal,
itemCount: listtest.length,
itemBuilder: (context, index) {
return index == listtest[index]
? SizedBox(width: 10)
: Card(
margin: EdgeInsets.only(right: 8.0),
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.all(Radius.circular(10.0))),
child: Container(
height: 400,
width: 370,
decoration: BoxDecoration(
color: Colors.white,
borderRadius: BorderRadius.circular(10.0),
),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
GestureDetector(
onTap: () {
Navigator.pushNamed(context, 'HouseDetails');
},
child: Container(
height: 260,
decoration: BoxDecoration(
image: DecorationImage(
fit: BoxFit.fill,
image: AssetImage(images[index])),
borderRadius: BorderRadius.only(
topLeft: Radius.circular(10.0),
topRight: Radius.circular(10.0),
)),
),
),
Container(
padding: EdgeInsets.all(8.0),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Text(
listtest[index]['name'].toString(),
style: kh4,
),
SizedBox(
height: 2,
),
Text(
addresses[index],
style:
TextStyle(color: Colors.grey, fontSize: 10),
maxLines: 1,
overflow: TextOverflow.ellipsis,
),
SizedBox(
height: 2,
),
IntrinsicHeight(
child: Row(
children: [
Text(
'3 ',
style: TextStyle(
fontWeight: FontWeight.bold,
fontSize: 12),
),
Text(
'bds ',
style: TextStyle(fontSize: 12),
),
VerticalDivider(
width: 1,
color: Colors.grey,
),
Text(
' 5 ',
style: TextStyle(
fontWeight: FontWeight.bold,
fontSize: 12),
),
Text(
'baths ',
style: TextStyle(fontSize: 12),
),
VerticalDivider(
width: 1,
color: Colors.grey,
),
Text(
' 1750 ',
style: TextStyle(
fontWeight: FontWeight.bold,
fontSize: 12),
),
Text(
'sqft',
style: TextStyle(fontSize: 12),
),
],
),
),
Row(
crossAxisAlignment: CrossAxisAlignment.center,
children: [
Column(
crossAxisAlignment:
CrossAxisAlignment.start,
children: [
SizedBox(
height: 7,
),
Text(
'Starting Price',
style: TextStyle(
fontSize: 12,
),
),
Text(
prices[index],
style: TextStyle(
color: primaryColor,
fontWeight: FontWeight.bold,
fontSize: 11),
)
],
),
Spacer(),
HeartContainer(index)
],
)
],
),
)
],
),
),
);
}),
);

Answer 1

It seems to me listtest can be null. You should make sure you take that into account.
Try replacing listtest.length with listtest?.length ?? 0
and
listtest[index] with listtest?.elementAt(index)