E/颤振 (32633)： [错误：颤振/lib/ui/ui_dart_state.cc(177)] 未处理的异常： NoSuchMethod错误： 在空值上调用了 getter 'statusCo

Question

E/flutter(32633(：[错误：flutter/lib/ui/ui_start_state.cc(177(]未处理的异常：NoSuchMethodError：在null上调用了getter"statusCode"。E/flutter(32633(：接收器：空E/flutter(32633(：尝试调用：statusCodeE/flutter(32633(：#0 Object.noSuchMethod(dart:core-patch/Object_patch.dart:51:5(E/flutter(32633(：#1 APIService.createCustomerE/flutter(32633(：#2 _SignupPageState_formUI。

class APIService {
Future<bool> createCustomer(CustomerModel model) async {
var authToken = base64.encode(
utf8.encode(Config.key + ':' + Config.sceret),
);
bool ret = false;
Dio dio = Dio();
if (Platform.isAndroid) {
(dio.httpClientAdapter as DefaultHttpClientAdapter).onHttpClientCreate =
(client) {
client.badCertificateCallback =
(X509Certificate cert, String host, int port) => true;
return client;
};
}
try {
var response = await Dio().post(Config.url + Config.customerURL,
data: model.toJson(),
options: new Options(headers: {
HttpHeaders.authorizationHeader: 'Basic $authToken',
HttpHeaders.contentTypeHeader: 'application/json'
}));
if (response.statusCode == 201) {
ret = true;
}
} on DioError catch (e) {
if (e.response.statusCode == 404) {
ret = false;
} else {
ret = false;
}
}
return ret;
}
}

class SignupPage extends StatefulWidget {
@override
_SignupPageState createState() => _SignupPageState();
}
class _SignupPageState extends State<SignupPage> {
APIService apiService;
CustomerModel model;
GlobalKey<FormState> globalKey = GlobalKey<FormState>();
bool hidePassword = true;
bool isApiCallProcess = false;
@override
void initState() {
apiService = new APIService();
model = new CustomerModel();
super.initState();
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
backgroundColor: Colors.red,
automaticallyImplyLeading: true,
title: Text('Sign Up'),
),
body: ProgressHUD(
child: Form(
key: globalKey,
child: _formUI(),
),
inAsyncCall: isApiCallProcess,
opacity: 0.3),
);
}
Widget _formUI() {
return SingleChildScrollView(
child: Padding(
padding: EdgeInsets.all(10.00),
child: Container(
child: Align(
alignment: Alignment.topLeft,
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
FormHelper.fieldLabel('First Name'),
FormHelper.textInput(
context,
model.firstName,
(value) => {
this.model.firstName = value,
},
onValidate: (value) {
if (value.toString().isEmpty) {
return 'Please enter First Name.';
}
return null;
},
),
FormHelper.fieldLabel('Last Name'),
FormHelper.textInput(
context,
model.lastName,
(value) => {
this.model.lastName = value,
},
onValidate: (value) {
return null;
},
),
FormHelper.fieldLabel('Email Id'),
FormHelper.textInput(
context,
model.email,
(value) => {
this.model.email = value,
},
onValidate: (value) {
if (value.toString().isEmpty) {
return 'Please enter Email id.';
}
if (value.isNotEmpty && !value.toString().isValidEmail()) {
return 'Please enter valid email id';
}
return null;
},
),
FormHelper.fieldLabel('Password'),
FormHelper.textInput(
context,
model.password,
(value) => {
this.model.password = value,
},
onValidate: (value) {
if (value.toString().isEmpty) {
return 'Please enter Password.';
}
return null;
},
obscureText: hidePassword,
suffixIcon: IconButton(
onPressed: () {
setState(() {
hidePassword = !hidePassword;
});
},
color: Theme.of(context).accentColor.withOpacity(0.4),
icon: Icon(
hidePassword ? Icons.visibility_off : Icons.visibility,
),
),
),
SizedBox(
height: 20,
),
Center(
child: FormHelper.saveButton(
'Register',
() {
if (validateAndSave()) {
print(model.toJson());
setState(() {
isApiCallProcess = true;
});
apiService.createCustomer(model).then(
(ret) {
setState(() {
isApiCallProcess = false;
});
if (ret) {
FormHelper.showMessage(
context,
'WooCommerce App',
'Registration Successfull',
'Ok',
() {
Navigator.of(context).pop();
},
);
} else {
FormHelper.showMessage(
context,
'WooCommerce App',
'Email Id already registered.',
'Ok',
() {
Navigator.of(context).pop();
},
);
}
},
);
}
},
),
)
],
),
),
),
),
);
}
bool validateAndSave() {
final form = globalKey.currentState;
if (form.validate()) {
form.save();
return true;
}
return false;
}
}

Answer 1

指向statusCode的错误NoSuchMethodError: The getter 'statusCode' was called on null是在null方法上调用的。此问题的可能原因是response为空。

我建议先用var response = Response();初始化response，然后尝试对URL使用字符串插值'${Config.url}${Config.customerURL}'，而不是使用+运算符。

var response = Response();
try {
response = await Dio().post('${Config.url}${Config.customerURL}',
data: model.toJson(),
options: new Options(headers: {
HttpHeaders.authorizationHeader: 'Basic $authToken',
HttpHeaders.contentTypeHeader: 'application/json'
}));
// ...
} on DioError catch (e) {
// ...
}
}