How to access an item from a json through FutureBuilder? - flutter

Question

i'm getting a json and would like to access certain items.
The method below returns the json I need to access.
search(cpf) async {
try {
final response = await http.get(
Uri.parse(BaseUrl.baseUrl + 'api/produtor/serach/$data'));
if (response.statusCode == 200) {
final jsonMap = jsonDecode(response.body) as Map<String, dynamic>;
final user = User.fromJson(jsonMap);
return user;
} else {
throw Exception("Error");
}
} catch (e) {
throw Exception(e.toString());
}
}
I created this example to try to access the items.
Future? _list;
#override
void initState() {
super.initState();
_list = widget.produtorServices.buscaProdutorPorCPF("56039891653");
}
Widget build(BuildContext context) {
return new Scaffold(
body: Container(
child: FutureBuilder(
future: widget.produtorServices.buscaProdutorPorCPF("56039891653"),
builder: (BuildContext context, AsyncSnapshot snapshot) {
if (snapshot.connectionState != ConnectionState.done) {
return const Center(child: CircularProgressIndicator());
}
if (snapshot.hasError) {
return Text("${snapshot.error}");
}
if (!snapshot.hasData) {
return Text("Null returned");
}
final user = snapshot.data as Produtor;
return Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Text('${user.id}: ${user.name}'),
],
); //Text(snapshot.data!.ip);
},
),
),
);
}
}
Here is json
[
{
"user":{
"roles":[
"622f533b5ee724631428f469"
],
"_id":"622f78fbf297571510cb4e32",
"nome":"XXXX",
"email":"teste#teste.com"
}
}
]
How do I add eg a text widget and access the json item?
I've already tried to solve using the model too. I declare User user and then I try to access the variable like this: user.name
But I get the error:
Error: Exception: Expected a value of type 'Map<String, dynamic>', but got one of type 'List'
I appreciate if anyone can help me analyze this!

Answer 1

You create two data classes to hold your JSON object.
class Users {
List<User> users;
Users({
required this.users,
});
factory Users.fromJson(Map<String, dynamic> json) => Users(
users: (json['users'] as List<dynamic>)
.map((e) => User.fromJson(e as Map<String, dynamic>))
.toList(),
);
}
class User {
List<String>? roles;
String? id;
String? nome;
String? email;
User({
this.roles,
this.id,
this.nome,
this.email,
});
factory User.fromJson(Map<String, dynamic> json) => User(
roles: (json['roles'] as List<dynamic>?)?.map((e) =>
e as String).toList(),
id: json['id'] as String?,
nome: json['nome'] as String?,
email: json['email'] as String?,
);
}
Then in your search method:
if (response.statusCode == 200) {
final jsonMap = jsonDecode(response.body) as Map<String, dynamic>;
final users = Users.fromJson(jsonMap);
return users;
} else {
throw Exception("Error");
}
In your FutureBuilder:
if (snapshot.connectionState != ConnectionState.done) {
return const Center(child: CircularProgressIndicator());
}
if (snapshot.hasError) {
return Text("${snapshot.error}");
}
if (!snapshot.hasData) {
return Text("Null returned");
}
final userList = snapshot.data as Users;
return Column(
mainAxisAlignment: MainAxisAlignment.center,
children: List<Text>.generate(
userList.users.length,
(index) {
final user = userList.users[index];
return Text('${user.id}: ${user.nome}, ${user.email}, ${user.roles}');
},
),
); //Text(snapshot.data!.ip);