In my project i accessed my model with api request. but when i run it it throws "Null check operator used on a null value" i've used the same method before and it works fine. i don't know what happened on this one.
my model
class Client {
List<Clients>? clients;
Client({this.clients});
Client.fromJson(Map<String, dynamic> json) {
if (json['clients'] != null) {
clients = <Clients>[];
json['clients'].forEach((v) {
clients!.add(new Clients.fromJson(v));
});
}
}
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = new Map<String, dynamic>();
if (this.clients != null) {
data['clients'] = this.clients!.map((v) => v.toJson()).toList();
}
return data;
}
}
class Clients {
int? id;
String? name;
String? address;
String? tinNo;
String? status;
String? createdAt;
String? updatedAt;
List<Phones>? phones;
Clients(
{this.id,
this.name,
this.address,
this.tinNo,
this.status,
this.createdAt,
this.updatedAt,
this.phones});
Clients.fromJson(Map<String, dynamic> json) {
id = json['id'];
name = json['name'];
address = json['address'];
tinNo = json['tin_no'];
status = json['status'];
createdAt = json['created_at'];
updatedAt = json['updated_at'];
if (json['phones'] != null) {
phones = <Phones>[];
json['phones'].forEach((v) {
phones!.add(new Phones.fromJson(v));
});
}
}
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = new Map<String, dynamic>();
data['id'] = this.id;
data['name'] = this.name;
data['address'] = this.address;
data['tin_no'] = this.tinNo;
data['status'] = this.status;
data['created_at'] = this.createdAt;
data['updated_at'] = this.updatedAt;
if (this.phones != null) {
data['phones'] = this.phones!.map((v) => v.toJson()).toList();
}
return data;
}
}
class Phones {
int? id;
String? clientId;
Null? supplierId;
Null? companyId;
String? phoneNumber;
String? email;
String? model;
String? category;
String? createdAt;
String? updatedAt;
Phones(
{this.id,
this.clientId,
this.supplierId,
this.companyId,
this.phoneNumber,
this.email,
this.model,
this.category,
this.createdAt,
this.updatedAt});
Phones.fromJson(Map<String, dynamic> json) {
id = json['id'];
clientId = json['client_id'];
supplierId = json['supplier_id'];
companyId = json['company_id'];
phoneNumber = json['phone_number'];
email = json['email'];
model = json['model'];
category = json['category'];
createdAt = json['created_at'];
updatedAt = json['updated_at'];
}
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = new Map<String, dynamic>();
data['id'] = this.id;
data['client_id'] = this.clientId;
data['supplier_id'] = this.supplierId;
data['company_id'] = this.companyId;
data['phone_number'] = this.phoneNumber;
data['email'] = this.email;
data['model'] = this.model;
data['category'] = this.category;
data['created_at'] = this.createdAt;
data['updated_at'] = this.updatedAt;
return data;
}
}
for my project i'm using paginated data table and accessing this data. the code is as follows. i've used the data as datasList[0].clients![index].address.toString(), in my datatablesource. and passed that data as
DataTableSource dataSource(List<Client> userList) =>
MyTable(datasList: userList, context: context);
data source
source: dataSource(
clientController.foundClients.value)
the error is when i use the ! operator. so how can i use this properly?
where the code being used
Container(
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(15),
border: Border.all(color: Colors.grey)),
child: Padding(
padding: EdgeInsets.symmetric(horizontal: width * 0.01),
child: Obx(() {
return clientController.clientPress
? const Center(child: CircularProgressIndicator())
: PaginatedDataTable(
sortColumnIndex: sortColumnIndex,
sortAscending: isAscending,
columns: [
DataColumn(
label: const Text("Id"),
onSort: (sortColumnIndex, ascending) {
setState(() {
isAscending = !isAscending;
});
// onSort(sortColumnIndex, ascending);
}),
DataColumn(
label: const Text("Name"),
onSort: (sortColumnIndex, ascending) {
setState(() {
isAscending = !isAscending;
});
//onSort(sortColumnIndex, ascending);
}),
DataColumn(
label: const Text("Address"),
onSort: (sortColumnIndex, ascending) {
setState(() {
isAscending = !isAscending;
});
//onSort(sortColumnIndex, ascending);
}),
DataColumn(
label: const Text("Tin No"),
onSort: (sortColumnIndex, ascending) {
setState(() {
isAscending = !isAscending;
});
// onSort(sortColumnIndex, ascending);
}),
const DataColumn(label: Text("Status")),
const DataColumn(label: Text("Created At")),
const DataColumn(label: Text("Actions")),
],
header: Row(
mainAxisAlignment:
MainAxisAlignment.spaceBetween,
children: [
!isSearch
? Expanded(
child: Row(
mainAxisAlignment:
MainAxisAlignment.spaceBetween,
children: [
Text(
"Manage Users",
style: TextStyle(
fontSize: width * 0.04,
fontWeight:
FontWeight.normal),
),
IconButton(
onPressed: () {
setState(() {
isSearch = !isSearch;
});
},
icon: Icon(Icons.search))
],
),
)
: ConstrainedBox(
constraints: BoxConstraints(
maxWidth: width * 0.5),
child: SizedBox(
width: width * 0.6,
child: TextField(
decoration: InputDecoration(
suffixIcon: IconButton(
onPressed: () {
setState(() {
searchController
.clear;
// userController
// .filterUser('');
isSearch = !isSearch;
});
},
icon: const Icon(
Icons.close)),
hintText: "search"),
onChanged: (text) {
text = text.toLowerCase();
// userController.filterUser(text);
},
),
),
),
MaterialButton(
onPressed: () {
showMaterialModalBottomSheet(
context: context,
builder: (context) => SizedBox(
height: height * 0.9,
// child: BottomSheetWidget(),
),
shape: const RoundedRectangleBorder(
borderRadius: BorderRadius.only(
topLeft: Radius.circular(15),
topRight:
Radius.circular(15))));
},
color: const Color.fromRGBO(30, 119, 66, 1),
shape: RoundedRectangleBorder(
borderRadius:
BorderRadius.circular(10)),
child: Text(
"Add User",
style: TextStyle(
color: Colors.white,
fontSize: width * 0.03),
),
)
],
),
source: dataSource(
clientController.foundClients.value));
})),
)
this is how I'm passing the fetch to my list using Getx
import 'package:get/get.dart';
import 'package:store_mgt_project/models/client/client_api.dart';
import 'package:store_mgt_project/models/client/client_model.dart';
class ClientController extends GetxController {
final _clientPress = false.obs;
get clientPress => _clientPress.value;
set clientPress(value) => _clientPress.value = value;
var allCLients = <Client>[].obs;
var foundClients = <Client>[].obs;
@override
void onInit() {
super.onInit();
fetchClient().then(
(value) => {allCLients.value = value, foundClients.value = allCLients});
}
@override
void onReady() {
super.onReady();
}
@override
void onClose() {}
void filterClient(String user, int index) {
List<Client> results = [];
if (user.isEmpty) {
results = allCLients;
} else {
results = allCLients.where((element) {
var _name = element.clients![index].name!.toLowerCase();
var _username = element.clients![index].address!.toLowerCase();
return _name.contains(user.toLowerCase()) ||
_username.contains(user.toLowerCase());
}).toList();
}
foundClients.value = results;
}
setclientPress(bool value) {
clientPress = value;
update();
}
}
so in the code I'm using controller and getting the datas
CodePudding user response：
Try the following code:
class Client {
List<Clients>? clients;
Client({this.clients});
Client.fromJson(Map<String, dynamic> json) {
if (json['clients'] != null) {
clients = <Clients>[];
json['clients'].forEach((v) {
clients?.add(new Clients.fromJson(v));
});
}
}
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = new Map<String, dynamic>();
if (this.clients != null) {
data['clients'] = this.clients?.map((v) => v.toJson()).toList();
}
return data;
}
}
class Clients {
int? id;
String? name;
String? address;
String? tinNo;
String? status;
String? createdAt;
String? updatedAt;
List<Phones>? phones;
Clients(
{this.id,
this.name,
this.address,
this.tinNo,
this.status,
this.createdAt,
this.updatedAt,
this.phones});
Clients.fromJson(Map<String, dynamic> json) {
id = json['id'];
name = json['name'];
address = json['address'];
tinNo = json['tin_no'];
status = json['status'];
createdAt = json['created_at'];
updatedAt = json['updated_at'];
if (json['phones'] != null) {
phones = <Phones>[];
json['phones'].forEach((v) {
phones?.add(new Phones.fromJson(v));
});
}
}
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = new Map<String, dynamic>();
data['id'] = this.id;
data['name'] = this.name;
data['address'] = this.address;
data['tin_no'] = this.tinNo;
data['status'] = this.status;
data['created_at'] = this.createdAt;
data['updated_at'] = this.updatedAt;
if (this.phones != null) {
data['phones'] = this.phones?.map((v) => v.toJson()).toList();
}
return data;
}
}
class Phones {
int? id;
String? clientId;
Null? supplierId;
Null? companyId;
String? phoneNumber;
String? email;
String? model;
String? category;
String? createdAt;
String? updatedAt;
Phones(
{this.id,
this.clientId,
this.supplierId,
this.companyId,
this.phoneNumber,
this.email,
this.model,
this.category,
this.createdAt,
this.updatedAt});
Phones.fromJson(Map<String, dynamic> json) {
id = json['id'];
clientId = json['client_id'];
supplierId = json['supplier_id'];
companyId = json['company_id'];
phoneNumber = json['phone_number'];
email = json['email'];
model = json['model'];
category = json['category'];
createdAt = json['created_at'];
updatedAt = json['updated_at'];
}
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = new Map<String, dynamic>();
data['id'] = this.id;
data['client_id'] = this.clientId;
data['supplier_id'] = this.supplierId;
data['company_id'] = this.companyId;
data['phone_number'] = this.phoneNumber;
data['email'] = this.email;
data['model'] = this.model;
data['category'] = this.category;
data['created_at'] = this.createdAt;
data['updated_at'] = this.updatedAt;
return data;
}
}
CodePudding user response：
Change your Client model to this, to make sure always have value:
class Client {
List<Clients> clients;
Client({required this.clients});
static Client fromJson(Map<String, dynamic> json) {
if (json['clients'] != null) {
var _clients = <Clients>[];
json['clients'].forEach((v) {
_clients.add(new Clients.fromJson(v));
});
return Client(clients: _clients);
} else {
return Client(clients: []);
}
}
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = new Map<String, dynamic>();
if (this.clients != null) {
data['clients'] = this.clients!.map((v) => v.toJson()).toList();
}
return data;
}
}