[英]Getting error during late initialisation in flutter
我正在調用下面的表單進行添加和編輯操作。當單擊編輯按鈕時，我必須根據其唯一 ID 獲取特定文檔的詳細信息，因此當單擊編輯時，我在 initState() 中調用 API，但是當單擊添加按鈕時，我我面臨着 futureDocuments 未初始化的問題，我也無法將其初始化為 null，如何解決？ 我也收到類似 dId 未初始化的錯誤，同時點擊添加文檔按鈕請指導我進行初始化
class DocumentForm extends StatefulWidget {
bool update;
final String userName;
//final String createdBY;
DocumentForm(this.userName, this.update);
@override
State createState() {
return _DocumentFormState(this.userName, this.update);
}
}
// AddAppointmentState<AddDocument> createState() => _AddDocumentState();
class _DocumentFormState extends State<DocumentForm> {
final String userName;
String playerId = '';
bool update;
//final String createdBY;
_DocumentFormState(this.userName, this.update);
late final String date1;
late String datainput;
final List<String> items1 = ["Open", "Closed", "Cancel", "Submitted"];
String? selectedItem;
final GlobalKey<FormState> formKey = GlobalKey<FormState>();
TextEditingController docIdController = TextEditingController();
TextEditingController docTitleController = TextEditingController();
TextEditingController tokenNoController = TextEditingController();
TextEditingController addressController = TextEditingController();
TextEditingController cityController = TextEditingController();
TextEditingController docStatusController = TextEditingController();
TextEditingController docTypeController = TextEditingController();
TextEditingController partyNameController = TextEditingController();
TextEditingController durationController = TextEditingController();
TextEditingController pinCodeController = TextEditingController();
TextEditingController rentDescController = TextEditingController();
TextEditingController startDateController = TextEditingController();
TextEditingController endDateController = TextEditingController();
late TextEditingController docstatusController = TextEditingController();
late String docType = docTypeController.text;
late final String createdBY;
final List<String> items = [
"Residential",
"Commercial",
];
String? selectedValue;
late Future<Document>? futureDocuments;
@override
void initState() {
this.update == true
? futureDocuments = DocumentController.fetchDocumentsByID(this.dId)
: futureDocuments = null;
// TODO: implement initState
super.initState();
// initPlatformState();
// initPlatformStateApt();
init();
}
@override
void dispose() {
docStatusController.dispose();
docTypeController.dispose();
super.dispose();
}
Future init() async {
// initPlatformState();
}
@override
Future<Document>? _futureDocument;
body: SafeArea(
child: SingleChildScrollView(
child: Container(
// height: MediaQuery.of(context).size.height,
//width: width * 1,
//height: MediaQuery.of(context).size.height,
alignment: Alignment.center,
padding: const EdgeInsets.all(25),
child: (_futureDocument == null)
? buildColumn(update)
: buildFutureBuilder(),
decoration: BoxDecoration(
color: Colors.white,
borderRadius: BorderRadius.only(
topLeft: Radius.circular(10),
topRight: Radius.circular(10))),
),
),
),
Form buildColumn(bool update) {
return Form(
key: formKey,
child: FutureBuilder<Document>(
future: futureDocuments,
builder: (context, snapshot) {
if (snapshot.connectionState == ConnectionState.done) {
if (snapshot.hasData) {
createdBY = snapshot.data!.createdBy;
this.dId = snapshot.data!.docId;
return Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
SizedBox(
height: 5,
),
// SizedBox(
// height: MediaQuery.of(context).size.height * 0.06,
// width: MediaQuery.of(context).size.width * 8,
// child:
Align(
alignment: Alignment.topLeft,
child: SizedBox(
width: MediaQuery.of(context).size.width * 0.95,
height: MediaQuery.of(context).size.height * 0.06,
// height: MediaQuery.of(context).size.height * 0.5,
child: TextFormField(
// minLines: 1,
// maxLines: 5,
// textCapitalization: TextCapitalization.words,
// //autovalidateMode: AutovalidateMode.onUserInteraction,
inputFormatters: [
// LengthLimitingTextInputFormatter(100),
FilteringTextInputFormatter.allow(
RegExp("[ ',-/ a-z A-Z á-ú Á-Ú 0-9]")),
],
controller: this.update == true
? docTitleController = TextEditingController(
text: '${snapshot.data!.docTitle}')
: docTitleController,
style: TextStyle(fontSize: 12),
// keyboardType: TextInputType.multiline,
decoration: const InputDecoration(
errorStyle: const TextStyle(fontSize: 0.05),
border: OutlineInputBorder(
borderRadius: BorderRadius.all(
Radius.circular(30),
)),
hintStyle: TextStyle(fontSize: 12),
labelStyle: TextStyle(
fontSize: 12,
),
labelText: 'Document Title',
hintText: 'Document title required'),
// validator: ,
validator: MultiValidator(
[RequiredValidator(errorText: 'Required*')]),
),
),
),
SizedBox(
height: 20,
),
Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
Align(
alignment: Alignment.topLeft,
child: SizedBox(
height: MediaQuery.of(context).size.height * 0.06,
width: MediaQuery.of(context).size.width * 0.4,
child: TextFormField(
style: TextStyle(
fontSize: 12,
),
// minLines: 1,
// maxLines: 2,
inputFormatters: [
FilteringTextInputFormatter.digitsOnly,
LengthLimitingTextInputFormatter(14)
],
// //autovalidateMode: AutovalidateMode.onUserInteraction,
controller: this.update == true
? tokenNoController = TextEditingController(
text: '${snapshot.data!.tokenNo}')
: tokenNoController,
keyboardType: TextInputType.number,
decoration: const InputDecoration(
errorStyle: const TextStyle(fontSize: 0.05),
counterText: "",
border: OutlineInputBorder(
borderRadius:
BorderRadius.all(Radius.circular(30)),
),
focusColor: Color.fromARGB(255, 3, 87,
156), //Color.fromARGB(255, 253, 153, 33),
hintStyle: TextStyle(fontSize: 12),
labelStyle: TextStyle(
fontSize: 12,
),
labelText: 'Token No',
hintText: 'Token no required'),
validator: (value) {
if (value == null || value.isEmpty) {
return 'Please enter token No';
} else if (value.length < 14) {
return 'Please enter 14 digits number';
}
return null;
},
),
),
),
SizedBox(
width: MediaQuery.of(context).size.width * 0.01,
),
Align(
alignment: Alignment.topLeft,
child: SizedBox(
height: MediaQuery.of(context).size.height * 0.06,
width: MediaQuery.of(context).size.width * 0.4,
child: TextFormField(
style: TextStyle(fontSize: 12),
// minLines: 1,
// maxLines: 2,
//autovalidateMode: AutovalidateMode.onUserInteraction,
inputFormatters: [
FilteringTextInputFormatter.digitsOnly,
LengthLimitingTextInputFormatter(2)
],
controller: this.update == true
? durationController = TextEditingController(
text: '${snapshot.data!.duration}')
: durationController,
keyboardType: TextInputType.number,
decoration: const InputDecoration(
errorStyle: const TextStyle(fontSize: 0.05),
border: OutlineInputBorder(
borderRadius: BorderRadius.all(
Radius.circular(30))),
hintStyle: TextStyle(fontSize: 12),
labelStyle: TextStyle(
fontSize: 12,
),
labelText: 'Duration(M)',
hintText: 'Duration required'),
validator: MultiValidator(
[RequiredValidator(errorText: 'Required*')],
),
),
),
),
],
),
SizedBox(
height: 20,
),
Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
Align(
alignment: Alignment.topLeft,
child: SizedBox(
height: MediaQuery.of(context).size.height * 0.06,
width: MediaQuery.of(context).size.width * 0.4,
child: TextFormField(
style: TextStyle(fontSize: 12),
// //autovalidateMode: AutovalidateMode.onUserInteraction,
//FilteringTextInputFormatter.allow(RegExp("[- 0-9]")),
inputFormatters: [
FilteringTextInputFormatter.allow(
RegExp("[- 0-9]")),
LengthLimitingTextInputFormatter(10)
],
controller: this.update == true
? startDateController = TextEditingController(
text: '${snapshot.data!.startDate}')
: startDateController,
keyboardType: TextInputType.datetime,
decoration: const InputDecoration(
errorStyle: const TextStyle(fontSize: 0.05),
prefixIcon: Icon(Icons.calendar_month),
border: OutlineInputBorder(
borderRadius:
BorderRadius.all(Radius.circular(30))),
hintStyle: TextStyle(fontSize: 12),
labelStyle: TextStyle(
fontSize: 12,
),
labelText: 'Start Date',
hintText: 'yyyy-MM-dd',
),
onTap: () async {
DateTime? pickedDate = await showDatePicker(
context: context,
initialDate: DateTime.now(),
firstDate: DateTime(
1991), //DateTime.now() - not to allow to choose before today.
lastDate: DateTime(2101),
// onConfirm:widget.onChanged,
).then((pickedDate) {
if (pickedDate != null) {
// print(
// pickedDate); //pickedDate output format => 2021-03-10 00:00:00.000
String formattedDate =
DateFormat('yyyy-MM-dd')
.format(pickedDate);
print(formattedDate);
setState(() {
startDateController.text = formattedDate;
//set output date to TextField value.
});
print(startDateController.text);
} else {
print("Date is not selected");
}
});
final int dur =
int.parse(durationController.text);
var stDate =
DateTime.parse(startDateController.text);
var jiffy = Jiffy(stDate).add(
months: dur,
days: -1,
// days: 1095,
);
DateTime d = jiffy.dateTime;
String s = jiffy.format('yyyy-MM-dd');
setState(() {
endDateController.text = s.toString();
});
},
validator: MultiValidator(
[RequiredValidator(errorText: 'Required*')]),
),
),
),
Row(
mainAxisAlignment: MainAxisAlignment.spaceAround,
children: [
Container(
height: 30,
width: 150,
child: ElevatedButton(
onPressed: () {
// ******Add new document **********///////
formKey.currentState?.validate();
final isValidForm =
formKey.currentState!.validate();
if (isValidForm && (update == false)) {
final String docTitle =
docTitleController.text;
final int tokenNo =
int.parse(tokenNoController.text)
.toInt();
//final String tokenNo = tokenNoController.text;
final String partyName =
partyNameController.text;
// addStatus(selectedItem!);
final String docType =
selectedValue.toString();
final String docStatus =
selectedItem.toString();
final String address =
addressController.text;
final String city = cityController.text;
final String rentDesc =
rentDescController.text;
final String pinCode =
pinCodeController.text;
final String duration =
durationController.text;
final String startDate =
startDateController.text;
final String endDate =
endDateController.text;
final String createdBy = this.userName;
print('Username :${createdBy}');
final String updatedBy = '';
Navigator.of(context).push(
MaterialPageRoute(
builder: (BuildContext context) =>
DocumentPage(
this.userName,
)));
setState(() {
_futureDocument = createDocument(
// docId,
docTitle,
tokenNo,
partyName,
docType,
address,
city,
pinCode,
duration,
rentDesc,
docStatus,
startDate,
endDate,
createdBy,
updatedBy,
// createdAt,
);
});
// }
//}
}
///*****************/
//****Edit document ******/
else if (isValidForm && update == true) {
final int docid = snapshot.data!.docId;
final String docTitle =
docTitleController.text;
final int tokenNo =
int.parse(tokenNoController.text)
.toInt();
final String partyName =
partyNameController.text;
final String docType =
docTypeController.text;
final String city = cityController.text;
final String address =
addressController.text;
final String pinCode =
pinCodeController.text;
final String duration =
durationController.text;
final String rentDesc =
rentDescController.text;
final String docStatus =
docstatusController.text;
final String startDate =
startDateController.text;
final String endDate =
endDateController.text;
final String createdBy = this.createdBY;
final String updatedBy = this.userName;
print(
'the user name from doc edit page ${this.userName}');
setState(() {
futureDocuments = updateDocument(
docid,
docTitle,
tokenNo,
partyName,
docType,
address,
city,
pinCode,
duration,
rentDesc,
docStatus,
startDate,
endDate,
createdBy,
updatedBy);
Navigator.of(context).push(
MaterialPageRoute(
builder: (BuildContext context) =>
DocumentsDetails(
docid,
this.userName,
)));
});
}
;
},
child: const Text("Save"),
style: ButtonStyle(
backgroundColor: MaterialStateProperty.all(
Color.fromARGB(255, 253, 153, 33),
//Color.fromARGB(255, 253, 153, 33)
),
shape: MaterialStateProperty.all<
RoundedRectangleBorder>(
RoundedRectangleBorder(
borderRadius:
BorderRadius.circular(18.0),
//side: BorderSide(color: Colors.red)
),
)))),
],
),
],
);
}
}
return Center(child: const CircularProgressIndicator());
}),
);
//])
//);
}
FutureBuilder<Document> buildFutureBuilder() {
return FutureBuilder<Document>(
future: _futureDocument,
builder: (context, snapshot) {
if (snapshot.hasData) {
return Text(snapshot.data!.docTitle);
} else if (snapshot.hasError) {
return Text('${snapshot.error}');
}
return const CircularProgressIndicator();
},
);
}
您可以延遲刪除，因為它已經可以為空。 並且您還必須在將 state 分配給futureDocuments后更新它。
使用?將late的值更改為nullable值操作員。 IE
改變自
late final String date1;
late String datainput;
到
final String? date1;
String? datainput;
現在您可以將null分配給date1和datainput ！
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