在颤振中清除文本字段时出现错误" getter 'year' was called on null "

Question

当我单击清除按钮时，它不会清除所有文本框，只会清除expiry_date字段，并向我显示异常"获取年份在空上调用"。

在此代码中，当我单击该按钮时，我有一个清除按钮，它不会清除该按钮并显示调用 null 的年份。我认为发生此问题是因为我已经在到期日期小部件中添加了更改。但我需要一个在线活动。所以我需要清除所有内容。希望你理解这个问题。你的帮助可以让我度过美好的一天。

这是代码：

class _BspLicensedSignupPageState extends State<BspLicensedSignupPage>
with AfterLayoutMixin<BspLicensedSignupPage> {
final GlobalKey<FormState> _formKey = GlobalKey<FormState>();
final TextEditingController _bspBusinessLicenseNumber =
TextEditingController();
final TextEditingController _bspLicenseAuthorityName =
TextEditingController();
final TextEditingController _bspLicenseExpiryDate = TextEditingController();
final format = new DateFormat.yMMMEd('en-US');
String _isoDate;
List<BusinessProfilePicture> _bspLicenseImages =
new List<BusinessProfilePicture>();
List<Object> images = List<Object>();
List<dynamic> _bspLicenseAuthorityTypes = <dynamic>[];
Map<String, dynamic> _bspLicenseAuthorityType;
bool _isvisibleissuingauthority = false;
bool businesslicensecheck = false;
int radioValue = -1;
Future<File> licenceimage;
Future<File> profilepicture;
DateTime date;
TimeOfDay time;
String _countryId;
BSPSignupRepository _bspSignupRepository = new BSPSignupRepository();
bool autovalidate = false;
bool _isEditMode = false;
int selected = 0;
List<String> _imageFilesList = [];
var isUploadingPost = false;
var isEditInitialised = true;
List<File> _licenseImages = [];

@override
void initState() {
super.initState();
_scrollController = ScrollController();
}
Widget _buildbusinesslicenseno() {
return new TudoTextWidget(
prefixIcon: Icon(FontAwesomeIcons.idCard),
controller: _bspBusinessLicenseNumber,
labelText: AppConstantsValue.appConst['licensedsignup']
['businesslicenseno']['translation'],
validator: Validators().validateLicenseno,
);
}
Widget _buildexpirydate() {
return DateTimeField(
format: format,
autocorrect: true,
autovalidate: false,
controller: _bspLicenseExpiryDate,
readOnly: true,
validator: (date) => (date == null || _bspLicenseExpiryDate.text == '')
? 'Please enter valid date'
: null,
onChanged: (date) {
_isoDate = DateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'").format(date);
},
decoration: InputDecoration(
labelText: "Expiry Date",
hintText: "Expiry Date",
prefixIcon: Icon(
FontAwesomeIcons.calendar,
size: 24,
)),
onShowPicker: (context, currentValue) {
return showDatePicker(
context: context,
firstDate: DateTime.now(),
initialDate: currentValue ?? DateTime.now(),
lastDate: DateTime(2100),
);
},
);
}
Widget _buildlicenseauthority() {
return new TudoTextWidget(
validator: (val) => Validators.validateName(val, "Issuing Authority"),
controller: _bspLicenseAuthorityName,
prefixIcon: Icon(Icons.account_circle),
labelText: AppConstantsValue.appConst['licensedsignup']
['licenseissuingauthority']['translation'],
hintText: AppConstantsValue.appConst['licensedsignup']
['licenseissuingauthority']['translation'],
);
}
Widget _buildlabeluploadlicensepicture() {
return Text(AppConstantsValue.appConst['licensedsignup']
['labeluploadlicenpicture']['translation']);
}

Widget _buildlegalbusinesscheck() {
return TudoConditionWidget(
text: AppConstantsValue.appConst['licensedsignup']['legalbusinesscheck']
['translation'],
);
}

Widget content(
BuildContext context, BspLicensedSignupViewModel bspLicensedSignupVm) {
final appBar = AppBar(
centerTitle: true,
title: Text("BSP Licensed Details"),
leading: IconButton(
icon: Icon(Icons.arrow_back_ios),
onPressed: () {
NavigationHelper.navigatetoBack(context);
},
),
);
final bottomNavigationBar = Container(
height: 56,
//margin: EdgeInsets.symmetric(vertical: 24, horizontal: 12),
child: Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: <Widget>[
new FlatButton.icon(
icon: Icon(Icons.close),
label: Text('Clear'),
color: Colors.redAccent,
textColor: Colors.black,
padding: EdgeInsets.symmetric(vertical: 10, horizontal: 30),
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(7),
),
//  onpress
onPressed: () {
_formKey.currentState.reset();
_bspBusinessLicenseNumber.clear();
_bspLicenseAuthorityName.clear();
_bspBusinessLicenseNumber.text = '';
_bspLicenseAuthorityName.text = '';
setState(() {
_licenseImages.clear();
_imageFilesList.clear();
});
},
),
new FlatButton.icon(
icon: Icon(FontAwesomeIcons.arrowCircleRight),
label: Text('Next'),
color: colorStyles["primary"],
textColor: Colors.white,
padding: EdgeInsets.symmetric(vertical: 10, horizontal: 30),
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(7),
),
onPressed: () async {
},
),
],
),
);
return new Scaffold(
appBar: appBar,
bottomNavigationBar: bottomNavigationBar,
body: Container(
height: double.infinity,
width: double.infinity,
child: Stack(
children: <Widget>[
// Background(),
SingleChildScrollView(
controller: _scrollController,
child: SafeArea(
top: false,
bottom: false,
child: Form(
autovalidate: autovalidate,
key: _formKey,
child: Scrollbar(
child: SingleChildScrollView(
dragStartBehavior: DragStartBehavior.down,
// padding: const EdgeInsets.symmetric(horizontal: 16.0),
child: new Container(
margin: EdgeInsets.fromLTRB(30, 30, 30, 0),
child: new Column(
mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: CrossAxisAlignment.center,
children: [
_buildbusinesslicenseno(),
_buildexpirydate(),
_buildlegalbusinesscheck()
],
),
),
),
),
),
),
),
],
),
),
);
}
@override
Widget build(BuildContext context) {
return new StoreConnector<AppState, BspLicensedSignupViewModel>(
converter: (Store<AppState> store) =>
BspLicensedSignupViewModel.fromStore(store),
onInit: (Store<AppState> store) {
_countryId = store.state.auth.loginUser.user.country.id.toString();
print('_countryId');
print(_countryId);
},
builder: (BuildContext context,
BspLicensedSignupViewModel bspLicensedSignupVm) =>
content(context, bspLicensedSignupVm),
);
}
}
}

Answer 1

onChanged中的格式化程序无法设置空日期的格式。 因此，您可以在DateTimeField的onChanged方法中添加空检查。

喜欢这个：

onChanged: (date) {
if (date != null){
_isoDate = DateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'").format(date);
}
}