Flutter:如何在按下“提交"按钮后使我的字段为必填字段并保存我的下拉菜单和文本数据? [英] Flutter: How to make my fields required and save my dropdown and text data after the submit button is pressed?
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问题描述
这是我的代码.我无法保存响应，甚至下拉菜单和文本字段也未显示所需的文本和*符号.我不知道如何保存用户提交的响应以及在何处进行保存，以及如何保存提交按钮上on Pressed函数上的内容以保存其上方所有字段的响应.
Here is my code. I'm unable to save the responses and even the dropdown and the text fields are not showing the required text and the * sign with them. I can't get how can I save the responses submitted by the user and where to do it and what should I write on the on Pressed function in the submit button to save the responses of all the fields above it.
import 'package:flutter/material.dart';
import 'package:flutter/cupertino.dart';
void main() {
runApp(MaterialApp(home: MyApp()));
}
class MyApp extends StatefulWidget {
@override
_MyAppState createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> {
TextEditingController problemBox = TextEditingController();
List _listItem = ["Category 1", "Category 2", "Category 3", "Category 4"];
List _listItem1 = [
"Sub Category 1",
"Sub Category 2",
"Sub Category 3",
"Sub Category 4"
];
List _listItem2 = ["CRIS", "ADMINISTRATION", "ZONE", "DEPARTMENT"];
String dropdownValue;
String holder = '';
void getDropDownItem() {
setState(() {
holder = dropdownValue;
});
}
String dropdownValue1;
String holder1 = '';
void getDropDownItem1() {
setState(() {
holder1 = dropdownValue1;
});
}
String dropdownValue2;
String holder2 = '';
void getDropDownItem2() {
setState(() {
holder2 = dropdownValue2;
});
}
bool autoValidate = true;
final GlobalKey<FormState> _formKey = GlobalKey<FormState>();
@override
Widget build(BuildContext context) {
return Scaffold(
resizeToAvoidBottomInset: false,
appBar: AppBar(
title: Text("Feedback"),
centerTitle: true,
leading: IconButton(
onPressed: () {},
icon: Icon(Icons.home),
),
),
body: Container(
child: Center(
child: SingleChildScrollView(
child: Form(
autovalidateMode: AutovalidateMode.onUserInteraction,
key: _formKey,
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
Text("CATEGORY"),
DropdownButton<String>(
hint: Text("Select"),
value: dropdownValue,
items: _listItem
.map<DropdownMenuItem<String>>((valueItem) {
return DropdownMenuItem<String>(
value: valueItem,
child: Text(valueItem),
);
}).toList(),
onChanged: (value) {
setState(() {
dropdownValue = value;
});
},
)
],
),
SizedBox(
height: 10,
),
Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
Text("SUBCATEGORY"),
DropdownButton<String>(
hint: Text("Select"),
value: dropdownValue1,
items: _listItem1
.map<DropdownMenuItem<String>>((valueItem1) {
return DropdownMenuItem<String>(
value: valueItem1,
child: Text(valueItem1),
);
}).toList(),
onChanged: (value) {
setState(() {
dropdownValue1 = value;
});
},
)
],
),
SizedBox(height: 10),
Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
Text("MARKED TO"),
DropdownButton<String>(
hint: Text("Select"),
value: dropdownValue2,
items: _listItem2
.map<DropdownMenuItem<String>>((valueItem2) {
return DropdownMenuItem<String>(
value: valueItem2,
child: Text(valueItem2),
);
}).toList(),
onChanged: (value) {
setState(() {
dropdownValue2 = value;
});
},
)
],
),
SizedBox(height: 10),
Column(
mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: CrossAxisAlignment.center,
children: [
Padding(
padding: EdgeInsets.fromLTRB(70, 00, 70, 00),
child: TextFormField(
validator: (String value) {
if (value.isEmpty) {
return "Name is required";
}
return null;
},
controller: problemBox,
decoration: InputDecoration(
hintText: "Describe your problem here.",
),
maxLength: 1000,
maxLines: 5,
),
)
],
),
SizedBox(height: 10),
ButtonTheme(
child: ElevatedButton(
child: Text("Submit"),
onPressed: () {
_formKey.currentState.save();
},
style: ElevatedButton.styleFrom(
padding: EdgeInsets.symmetric(
horizontal: 25, vertical: 15),
),
),
),
]),
),
),
)));
}
推荐答案
要显示textField的错误，请检查Form是否有效:
To show the error of the textField check if the Form is validate :
ButtonTheme(
child: ElevatedButton(
child: Text("Submit"),
onPressed: () {
if(
_formKey.currentState.validate() // add this
) {
print(" form is valideate"); // here do what you want when the form is validate :)
}
},
style: ElevatedButton.styleFrom(
padding: EdgeInsets.symmetric(
horizontal: 25, vertical: 15),
),
),
)
要验证dropDown，请将DropdownButton更改为DropdownButtonFormField具有属性验证器–
To validate dropDown , change DropdownButton to DropdownButtonFormField has a property validator –
Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
Flexible(child: Text("MARKED TO")),
Flexible(
child: DropdownButtonFormField<String>( // change to DropdownButtonFormField
hint: Text("Select"),
value: dropdownValue2,
validator: (value) => value == null ? 'your message' : null,// add validator property
items: _listItem2
.map<DropdownMenuItem<String>>((valueItem2) {
return DropdownMenuItem<String>(
value: valueItem2,
child: Text(valueItem2),
);
}).toList(),
onChanged: (value) {
setState(() {
dropdownValue2 = value;
});
},
),
)
],
),
对于*，您可以将其添加到必填字段
and for * you can juste add it to required fields
例如:
RichText(
textAlign: TextAlign.center,
text: TextSpan(
text: 'MARKED TO',
children: <TextSpan>[
TextSpan(
text: '*',
style: TextStyle(color: Colors.red),
),
],
),
)
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