Flutter error : Got the error on length and map - flutter

Question

I Got the error on length and map after upgrading flutter.
And the same code is running in the old project.
when I print only snapshot.data then data is not showing.
class _TabPageState extends State<TabPage> {
var response;
var medicineSubCategoryApi;
#override
void initState() {
super.initState();
fetchData(widget.medicineCatUniqId);
}
fetchData(var medicineCatUniqId) async {
var api = Uri.parse($baseUrl/productSubCatApi.php?a2rTokenKey=$a2rTokenKey&pcat=$medicineCatUniqId');
response = await http.get(
api,
);
print("medicineCatApiLnk " + api.toString());
print("medicineCat" + response.body);
medicineSubCategoryApi = jsonDecode(response.body);
print("medicineCatString" + medicineSubCategoryApi.toString());
return medicineSubCategoryApi;
// setState(() {});
}
#override
Widget build(BuildContext context) {
return MaterialApp(
home: FutureBuilder(
future: fetchData(medicineSubCategoryApi),
// initialData: medicineSubCategoryApi,
builder: (context, snapshot) {
if (snapshot.hasData) {
print(snapshot.data.length.toString());
print(snapshot.data.toString());
// API data will be stored as snapshot.data
return DefaultTabController(
length: snapshot.data.length,
child: Scaffold(
appBar: AppBar(
title: const Text('Tabbed AppBar'),
bottom: TabBar(
isScrollable: true,
tabs: snapshot.data
.map<Widget>((choice) => Tab(
text: choice['psubCatName'],
// icon: Icon(choice),
))
.toList(),
),
),
body: TabBarView(
physics: NeverScrollableScrollPhysics(),
children: snapshot.data.map<Widget>((choice) {
return Padding(
padding: const EdgeInsets.all(20.0),
child: ChoicePage(
choice: choice,
),
);
}).toList(),
),
),
);
} else if (snapshot.hasError) {
return Text('Error');
} else {
return Text('Loading');
}
}),
);
}
}
class ChoicePage extends StatelessWidget {
const ChoicePage({Key? key, this.choice}) : super(key: key);
final choice;
#override
Widget build(BuildContext context) {
final TextStyle? textStyle = Theme.of(context).textTheme.headline4;
return Card(
color: Colors.white,
child: Center(
child: Column(
mainAxisSize: MainAxisSize.min,
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
Text(
choice['psubCatName'],
style: textStyle,
),
],
),
),
);
}
}
when I print This thing I got then coming error.
class _TabPageState extends State<TabPage> {
var response;
var medicineSubCategoryApi;
#override
void initState() {
super.initState();
// for loading
fetchData(widget.medicineCatUniqId);
}
fetchData(var medicineCatUniqId) async {
var api = Uri.parse('$baseUrl/productSubCatApi.php?a2rTokenKey=$a2rTokenKey&pcat=$medicineCatUniqId');
response = await http.get(
api,
);
print("medicineCatApiLnk " + api.toString());
print("medicineCat" + response.body);
// in double quotes drink is key value of json
medicineSubCategoryApi = jsonDecode(response.body);
print("medicineCatString" + medicineSubCategoryApi.toString());
return medicineSubCategoryApi;
// setState(() {});
}
#override
Widget build(BuildContext context) {
return MaterialApp(
home: FutureBuilder(
future: fetchData(medicineSubCategoryApi),
// initialData: medicineSubCategoryApi,
builder: (context, snapshot) {
if (snapshot.hasData) {
print(snapshot.data.length.toString());
print(snapshot.data.toString());
return Column(
crossAxisAlignment: CrossAxisAlignment.center,
children: [
Text(snapshot.data.length.toString()),
Text(snapshot.data.toString()),
],
);
// API data will be stored as snapshot.data
}).toList(),
),
),
);
} else if (snapshot.hasError) {
return Text('Error');
} else {
return Text('Loading');
}
}),
);
}
}

Answer 1

try this
print(snapshot.data!.length!.toString());
print(snapshot.data!.toString());
it can solve the problem if you were not using Flutter 2.0 before