How to fix this Error Unexpected null value? - flutter

Question

I am getting the following error while rendering in my FutureBuilder:
======== Exception caught by rendering library =====================================================
The following TypeErrorImpl was thrown during paint(): Unexpected null value.
Here is my code:
file1.dart
DataCell(IconButton(
icon: Icon(Icons.info_outline),
onPressed: () {
showDialog(
context: context,
builder: (BuildContext context) {
return VendorDetailBox(document.data()['uid']);
});
},
)),
]);
file.dart
Widget build(BuildContext context) {
return FutureBuilder(
future: _services.vendors.doc(widget.uid).get(),
builder:
(BuildContext context, AsyncSnapshot<DocumentSnapshot> snapshot) {
if (snapshot.hasError) {
return Center(child: Text('Something Went Wrong'));
}
if (snapshot.connectionState == ConnectionState.waiting) {
return Center(child: CircularProgressIndicator());
}
return Dialog(
child: Container(
height: MediaQuery.of(context).size.height,
width: MediaQuery.of(context).size.width * .3,
child: ListView(children: [
Row(
crossAxisAlignment: CrossAxisAlignment.end,
children: [
SizedBox(
height: 100,
width: 100,
child: Image.network(
snapshot.data['url'],
fit: BoxFit.cover,
),
),
ListView(children: [
SizedBox(
width: 20,
),
Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Text(
snapshot.data['name'],
style: TextStyle(
fontWeight: FontWeight.bold, fontSize: 25),
),
Text(
snapshot.data['dialog'],
),
]),
]),
],
),
Divider(
thickness: 4,
),
Column(
children: [
Padding(
padding: const EdgeInsets.only(top: 10.0),
child: Row(
children: [
Expanded(
child: Container(
child: Text("Contact Numbers",
style: VendorDetailTextStyle),
),
),
Container(
child: Padding(
padding:
const EdgeInsets.only(left: 10.0, right: 10),
child: Text(':'),
),
),
Expanded(
child: Container(
child: Text(snapshot.data['mobile']),
),
),
],
),
),
Padding(
padding: const EdgeInsets.only(top: 10.0),
child: Row(
children: [
Expanded(
child: Container(
child: Text("Email", style: VendorDetailTextStyle),
)),
Container(
child: Padding(
padding:
const EdgeInsets.only(left: 10.0, right: 10),
child: Text(':'),
),
),
Expanded(
child: Container(
child: Text(snapshot.data['email']),
),
),
],
),
),
Padding(
padding: const EdgeInsets.only(top: 10.0),
child: Row(
children: [
Expanded(
child: Container(
child:
Text("address", style: VendorDetailTextStyle),
)),
Container(
child: Padding(
padding:
const EdgeInsets.only(left: 10.0, right: 10),
child: Text(':'),
),
),
Expanded(
child: Container(
child: Text(snapshot.data['address']),
),
),
],
),
),
// Padding(
// padding: const EdgeInsets.only(top: 10.0),
// child: Row(
// children: [
// Expanded(
// child: Container(
// child: Text("Created At",
// style: VendorDetailTextStyle),
// )),
// Container(
// child: Padding(
// padding:
// const EdgeInsets.only(left: 10.0, right: 10),
// child: Text(':'),
// ),
// ),
// Expanded(
// child: Container(
// child:
// Text(snapshot.data['Created At'].toString()),
// ),
// ),
// ],
// ),
// ),
],
),
]),
),
);
});
}