您好，我是新手，我是第一次收到此错误！ ，我实际上不知道为什么，但是它很奇怪，因为它运行得很好 错误是：必须为文本窗口小部件提供非空字符串。 'package：flutter / src / widgets / text.dart'： 断言失败：第360行pos 10：'data！= null' 我的注册状态代码：
class Register extends StatefulWidget {
@override
_RegisterState createState() => _RegisterState();
}
class _RegisterState extends State<Register> {
TextEditingController email = TextEditingController();
TextEditingController password = TextEditingController();
TextEditingController name = TextEditingController();
TextEditingController year = TextEditingController();
TextEditingController type = TextEditingController();
final _key = GlobalKey<FormState>();
bool _secureText = true ;
showHide(){
setState(() {
_secureText=!_secureText;
});
}
check(){
final form = _key.currentState;
if(form.validate()){
form.save();
register();
}
}
void register()async{
final response = await http.post('http://msc-mu.com/register.php',body: {
'email':email.text,
'password':password.text,
'name':name.text,
'year':year.text,
'type':type.text
});
final userdata = json.decode(response.body);
String emailApi = userdata[0]['email'];
String nameAPI = userdata[0]['name'];
String id = userdata[0]['id'];
String yearAPI = userdata[0]['year'];
String typeAPI = userdata[0]['type'];
setState(() {
savePref(token, emailApi, nameAPI, id, yearAPI, typeAPI);
print(savePref(token, emailApi, nameAPI, id, yearAPI, typeAPI));
});
return userdata;
}
var token ;
savePref(String token, String email, String name,String id, String year, String type)async{
SharedPreferences pref = await SharedPreferences.getInstance();
setState(() {
pref.setString('logged', token);
pref.setString('email', email);
pref.setString('name', name);
pref.setString('id', id);
pref.setString('year', year);
pref.setString('type', type);
pref.commit();
});
}
String _selectYear ;
List years = List();
Future<String> getYears()async{
final response = await http.get('http://msc-mu.com/getYears.php');
var resBody = json.decode(response.body);
setState(() {
years = resBody ;
}); }
String _selectType;
List types = List();
Future<String> getTypes ()async{
final response = await http.post('http://msc-mu.com/getlevel.php');
var resBody = json.decode(response.body);
setState(() {
types = resBody;
});
}
@override
void initState() {
// TODO: implement initState
year.text = _selectYear;
type.text = _selectType;
this.getYears();
this.getTypes();
super.initState();
}
@override
Widget build(BuildContext context) {
return Scaffold(
body: SingleChildScrollView(
child: Container(
height: MediaQuery.of(context).size.height,
child: Column(
children: <Widget>[
ClipPath(
clipper: OvalBottomBorderClipper(),
child: Image(
image: AssetImage('images/logo1.png'),
width: double.infinity,
height: MediaQuery.of(context).size.height / 3.5,
fit: BoxFit.cover,
),
),
Form(
key: _key,
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
SizedBox(
height: 25.0,
),
Card(
elevation: 6.0,
child: TextFormField(
controller: name,
validator: MinLengthValidator(8,
errorText: ('Name must be at least 8 digit long')),
style: TextStyle(
color: Colors.black,
fontSize: 16,
fontWeight: FontWeight.w300,
),
decoration: InputDecoration(
prefixIcon: Padding(
padding: EdgeInsets.only(left: 20, right: 15),
child: Icon(Icons.person, color: Colors.black),
),
contentPadding: EdgeInsets.all(18),
labelText: "FullName"),
),
),
Card(
elevation: 6.0,
child: TextFormField(
controller: email,
validator: EmailValidator(
errorText: 'Please enter a valid email address'),
style: TextStyle(
color: Colors.black,
fontSize: 16,
fontWeight: FontWeight.w300,
),
decoration: InputDecoration(
prefixIcon: Padding(
padding: EdgeInsets.only(left: 20, right: 15),
child: Icon(Icons.email, color: Colors.black),
),
contentPadding: EdgeInsets.all(18),
labelText: "Email"),
),
),
Card(
elevation: 6.0,
child: TextFormField(
controller: password,
validator: MultiValidator([
RequiredValidator(errorText: 'Password is Required'),
MinLengthValidator(8,
errorText:
'Password must be at least 8 digit long')
]),
obscureText: _secureText,
style: TextStyle(
color: Colors.black,
fontSize: 16,
fontWeight: FontWeight.w300,
),
decoration: InputDecoration(
suffixIcon: IconButton(
onPressed: showHide,
icon: Icon(_secureText
? Icons.visibility_off
: Icons.visibility),
),
prefixIcon: Padding(
padding: EdgeInsets.only(left: 20, right: 15),
child: Icon(Icons.phonelink_lock,
color: Colors.black),
),
contentPadding: EdgeInsets.all(18),
labelText: "Password"),
),
),
Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children:<Widget> [
Card(
elevation: 6.0,
child: DropdownButton<String>(
hint: Text('Choose your role'),
icon: Icon(Icons.arrow_drop_down),
iconSize: 24.0,
elevation: 16,
style: TextStyle(color: Colors.black, fontSize: 16.0),
underline: Container(
height: 2,
color: Theme.of(context).primaryColor,
),
items: types.map((item) {
return DropdownMenuItem(
child: Text(item['levelname']),
value: item['levelname'].toString(),
);
}).toList(),
onChanged: (newVal) {
setState(() {
_selectType = newVal;
type.text = _selectType;
});
},
value: _selectType,
),
),
Card(
elevation: 6.0,
child: DropdownButton<String>(
hint: Text('Choose your Year'),
icon: Icon(Icons.arrow_drop_down),
iconSize: 24.0,
elevation: 16,
style: TextStyle(color: Colors.black, fontSize: 16.0),
underline: Container(
height: 2,
color: Theme.of(context).primaryColor,
),
items: years.map((item) {
return DropdownMenuItem(
child: Text(item['name']),
value: item['name'].toString(),
);
}).toList(),
onChanged: (newVal){
setState(() {
_selectYear = newVal ;
year.text = _selectYear;
});
},
value: _selectYear,
),
),
],
),
SizedBox(height: 20.0,),
Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: [
SizedBox(
width: 150.0,
height: 44.0,
child: RaisedButton(
shape: RoundedRectangleBorder(
borderRadius:
BorderRadius.circular(15.0)),
child: Text(
"Register",
style: TextStyle(fontSize: 18.0),
),
textColor: Colors.white,
color: Theme.of(context).primaryColor,
onPressed: () {
check();
}),
),
SizedBox(
width: 150.0,
height: 44.0,
child: RaisedButton(
shape: RoundedRectangleBorder(
borderRadius:
BorderRadius.circular(15.0)),
child: Text(
"GoTo Login",
style: TextStyle(fontSize: 18.0),
),
textColor: Colors.white,
color: Theme.of(context).primaryColor,
onPressed: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => Login()),
);
}),
),
],
),
],
),
),
],
),
),
),
);
}
}
答案 0 :(得分：0)
有2件事：
item['levelname']为空：您的API调用返回Levelname（大写字母L）item['name']也为null，因为它不存在于API调用返回的js中。