how to display input value from text field to other pages? - flutter

I'm trying to display the input value below onto another page that contains radio buttons . my aim is that every time i write or change a value in a textfield it gets updated and displays onto a different page with the radio options . The snippet of code below is for the textfield - i used riverpod to connect it to firestore:
class AddMealPage extends ConsumerWidget {
const AddMealPage({Key? key}) : super(key: key);
static const String route = "/addMeal";
#override
Widget build(BuildContext context, WidgetRef ref) {
final model = ref.read(addMealProvider);
return LoadingLayer(
child: Scaffold(
appBar: AppBar(
elevation: 0,
iconTheme: const IconThemeData(
color: Colors.black,
),
title: const Text(
"Create Meal",
style: TextStyle(color: Colors.black, fontWeight: FontWeight.bold),
),
backgroundColor: Colors.white,
),
bottomNavigationBar: Padding(
padding: const EdgeInsets.fromLTRB(24, 0, 24, 24),
child: MaterialButton(
padding: const EdgeInsets.all(16),
color: Colors.black,
onPressed: model.enabled
? () async {
try {
await model.writeMeal();
Navigator.pop(context);
} catch (e) {
AppSnackbar(context).error(e);
}
}
: null,
child: const Text(
"Add meal",
style: TextStyle(color: Color.fromARGB(255, 247, 245, 245)),
),
),
),
body: SingleChildScrollView(
child: Container(
padding:
const EdgeInsets.symmetric(vertical: 60.0, horizontal: 10.0),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
GestureDetector(
onTap: () async {
final picked = await ImagePicker()
.pickImage(source: ImageSource.gallery);
if (picked != null) {
model.file = File(picked.path);
}
},
child: Container(
margin: const EdgeInsets.only(),
width: MediaQuery.of(context).size.width,
height: 210.0,
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(20),
image: (model.mealUrl != null || model.file != null)
? DecorationImage(
image: model.file != null
? FileImage(model.file!)
: NetworkImage(model.mealUrl!)
as ImageProvider,
fit: BoxFit.cover,
)
: null),
child: Column(
mainAxisAlignment: MainAxisAlignment.end,
crossAxisAlignment: CrossAxisAlignment.stretch,
children: [
if (model.mealUrl == null && model.file == null)
const Expanded(
child: Center(
child: Icon(
Icons.photo,
),
),
),
const Material(
color: Colors.transparent,
child: Padding(
padding: EdgeInsets.all(8.0),
),
),
],
),
),
),
const SizedBox(
height: 10,
),
const Padding(
padding: EdgeInsets.only(left: 15.0),
child: Text(
"Meal Name",
style: TextStyle(fontSize: 17, fontWeight: FontWeight.w500),
),
),
Container(
height: 50,
padding: const EdgeInsets.only(top: 10),
width: MediaQuery.of(context).size.width,
margin: const EdgeInsets.symmetric(horizontal: 20),
child: TextFormField(
textInputAction: TextInputAction.done,
initialValue: model.mealName,
maxLines: 1,
decoration: InputDecoration(
enabledBorder: OutlineInputBorder(
borderRadius: BorderRadius.circular(10),
borderSide: const BorderSide(color: Colors.grey),
),
focusedBorder: OutlineInputBorder(
borderRadius: BorderRadius.circular(5),
borderSide: const BorderSide(color: Colors.grey),
),
),
onChanged: (v) => model.mealName = v,
),
),
I want to display the input value i get from the textfield above in the format of a radioButton on a seperate page :
enum Variant { mealName }
class RadioOption extends StatefulWidget {
const RadioOption({Key? key}) : super(key: key);
#override
State<RadioOption> createState() => _RadioOptionState();
}
class _RadioOptionState extends State<RadioOption> {
Variant? _character = Variant.mealName;
#override
Widget build(BuildContext context) {
return Column(
children: <Widget>[
RadioListTile<Variant>(
title: const Text('$mealName'),
value: Variant.MealName,
groupValue: _character,
onChanged: (Variant? value) {
setState(() {
_character = value;
});
},
),

I don't see the whole architecture of the app. But if you want to transfer model.mealName, you can make String value (mealName) in your RadioOption, and pass it through the constructor:
final mealName;
RadioOption({required this.mealName});
And then access it in _RadioOptionState by:
title: const Text(widget.mealName);

You can use TextEditingController and add this controller to your TextFormField which have controller properties but you can't use initialValue and controller both so avoid initialValue. To put value you can use controller.text = your_value;
You value will be filled in text field.
To get value from TextFormField Use var newValue = controller.text; and send this newValue to another page in constructor.

Related

Field has not been initialized

tags in my code is a List which is comes from previous page,
I want to be able to remove and add items to it in my current page,
first I tried to initialize it in my initState but when I want to remove tags it doesn't work.
I guessed it is about the initialization, so I removed it from initState but now I am getting this error message Field 'tags' has not been initialized. I will attach my full code and I appreciate any suggestions about it. Thanks.
PS: I tried initializing tags with tags=[] in my initState but I can't remove any of the tags. It has a GestureDetector to remove tags, when I press it nothing happens. I guess initializing in the build function causes it, but I don't know where to initialize it that I could be able to edit it while the list is coming from another screen.
also when I added tags = widget.tags.where((e) => e != null && e != "").toList(); to my initiState and I inspect tags value, there is an empty string in addtion to other values at the end of the list.
import 'dart:convert';
import 'dart:developer';
import 'package:double_back_to_close/toast.dart';
import 'package:flutter/material.dart';
import 'package:pet_store/main.dart';
import 'package:pet_store/widgets/tag_preview.dart';
import 'package:image_picker/image_picker.dart';
import 'dart:io';
import 'dart:async';
import 'dart:math';
import 'package:http/http.dart' as http;
import 'package:pet_store/widgets/tag_retrieve_preview.dart';
import 'utils/utils.dart';
class update_pet extends StatefulWidget {
var id;
var name;
var status;
var category;
var tags ;
update_pet(
{this.id, this.name, this.status, this.category, this.tags, Key? key})
: super(key: key);
#override
_update_petState createState() => _update_petState();
}
class _update_petState extends State<update_pet> {
final _picker = ImagePicker();
Future<void> _openImagePicker() async {
final XFile? pickedImage =
await _picker.pickImage(source: ImageSource.gallery);
if (pickedImage != null) {
setState(() {
final bytes = File(pickedImage.path).readAsBytesSync();
base64Image = "data:image/png;base64," + base64Encode(bytes);
});
}
}
String? base64Image;
TextEditingController nameController = TextEditingController();
TextEditingController categoryController = TextEditingController();
TextEditingController tagController = TextEditingController();
late File imageFile;
late List<dynamic> tags;
bool isLoading = false;
void initState() {
super.initState();
nameController.text = widget.name;
categoryController.text = widget.category;
addTag();
}
void addTag() {
setState(() {
tags.add(tagController.text);
tagController.clear();
});
}
String? dropdownvalue;
var items = [
'available',
'pending',
'sold',
];
#override
Widget build(BuildContext context) {
tags = widget.tags.where((e) => e != null && e != "").toList();
// inspect(tags);
return Scaffold(
appBar: AppBar(
backgroundColor: Colors.indigo,
title: const Text('Update a pet'),
leading: GestureDetector(
child: Icon(
Icons.arrow_back_ios,
color: Colors.white,
),
onTap: () {
// Navigator.pop(context);
Navigator.pushAndRemoveUntil(
context,
MaterialPageRoute(
builder: (BuildContext context) =>
PetStoreHomePage(LoggedIn: true),
),
(route) => false,
);
},
),
),
body: GestureDetector(
onTap: () {
FocusScope.of(context).requestFocus(FocusNode());
},
child: SingleChildScrollView(
child: Column(
mainAxisSize: MainAxisSize.min,
children: <Widget>[
Card(
child: Container(
padding: const EdgeInsets.all(10),
child: Column(
children: [
const ListTile(
// leading,
title: Text(
"General Information",
style: TextStyle(fontWeight: FontWeight.bold),
),
),
TextField(
controller: nameController,
decoration: const InputDecoration(
border: OutlineInputBorder(),
labelText: "Enter your pet's name",
),
),
DropdownButton(
hint: const Text('Select Status'),
value: dropdownvalue,
icon: const Icon(Icons.keyboard_arrow_down),
items: items.map((String items) {
return DropdownMenuItem(
value: items,
child: Text(items),
);
}).toList(),
onChanged: (String? newValue) {
setState(() {
dropdownvalue = newValue!;
});
},
),
],
),
),
elevation: 8,
shadowColor: Colors.grey.shade300,
margin: const EdgeInsets.all(20),
shape: OutlineInputBorder(
borderRadius: BorderRadius.circular(10),
borderSide: const BorderSide(color: Colors.white)),
),
Card(
child: Container(
padding: const EdgeInsets.all(10),
child: Column(
children: [
const ListTile(
// leading,
title: Text(
"Category",
style: TextStyle(fontWeight: FontWeight.bold),
),
),
TextField(
controller: categoryController,
decoration: const InputDecoration(
border: OutlineInputBorder(),
labelText: "Specify your pet's category",
),
),
],
),
),
elevation: 8,
shadowColor: Colors.grey.shade300,
margin:
const EdgeInsets.symmetric(horizontal: 20, vertical: 10),
shape: OutlineInputBorder(
borderRadius: BorderRadius.circular(10),
borderSide: const BorderSide(color: Colors.white)),
),
Card(
child: Padding(
padding: const EdgeInsets.all(10.0),
child: Column(
mainAxisSize: MainAxisSize.min,
children: <Widget>[
const ListTile(
// leading,
title: Text(
"Tags",
style: TextStyle(fontWeight: FontWeight.bold),
),
),
Flexible(
fit: FlexFit.loose,
child: ListView.builder(
shrinkWrap: true,
itemCount: tags.length,
itemBuilder: (_, index) {
print(tags);
return Padding(
padding: const EdgeInsets.symmetric(
horizontal: 5.0, vertical: 3.0),
child: GestureDetector(
child: tagRetrievePreview(tags[index]),
onTap: () {
print("REMOVED "+tags[index]);
tags.removeAt(index);
}),
);
},
),
),
TextField(
controller: tagController,
decoration: InputDecoration(
border: OutlineInputBorder(),
labelText: "Specify your pet's tags",
suffixIcon: IconButton(
icon: const Icon(
Icons.add_circle_outline_sharp,
color: Color.fromARGB(255, 129, 128, 128),
size: 30,
),
onPressed: () {
addTag();
print(tags);
},
),
),
),
],
),
),
elevation: 8,
shadowColor: Colors.grey.shade300,
margin:
const EdgeInsets.symmetric(horizontal: 20, vertical: 10),
shape: OutlineInputBorder(
borderRadius: BorderRadius.circular(10),
borderSide: const BorderSide(color: Colors.white)),
),
Card(
child: Column(
children: [
const ListTile(
title: Text(
"Images",
style: TextStyle(fontWeight: FontWeight.bold),
),
),
(base64Image != null)
? SizedBox(
width: 100,
height: 100,
child: Container(
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(15),
image: DecorationImage(
image: image(base64Image!).image,
fit: BoxFit.fill),
)),
)
: SizedBox(
width: 100,
height: 100,
child: Container(
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(15),
color: Colors.grey.shade300,
),
child: Icon(
Icons.camera_alt,
color: Colors.grey.shade800,
size: 30,
),
),
),
Container(
margin: const EdgeInsets.symmetric(horizontal: 100),
child: ElevatedButton(
style: ButtonStyle(
backgroundColor: MaterialStateProperty.all(
const Color.fromARGB(255, 129, 128, 128)),
padding: MaterialStateProperty.all(
const EdgeInsets.symmetric(horizontal: 20)),
shape: MaterialStateProperty.all<
RoundedRectangleBorder>(
RoundedRectangleBorder(
borderRadius: BorderRadius.circular(10.0),
side: const BorderSide(
color: Color.fromARGB(255, 129, 128, 128),
width: 2.0,
),
),
),
),
child: const Text(
'Select Image',
style:
TextStyle(fontSize: 15.0, color: Colors.white),
),
onPressed: _openImagePicker),
),
],
),
elevation: 8,
shadowColor: Colors.grey.shade300,
margin:
const EdgeInsets.symmetric(horizontal: 20, vertical: 10),
shape: OutlineInputBorder(
borderRadius: BorderRadius.circular(10),
borderSide: const BorderSide(color: Colors.white)),
),
Container(
margin: const EdgeInsets.symmetric(horizontal: 120),
child: ElevatedButton(
style: ButtonStyle(
backgroundColor: MaterialStateProperty.all(Colors.indigo),
padding: MaterialStateProperty.all(
const EdgeInsets.symmetric(horizontal: 40)),
shape: MaterialStateProperty.all<RoundedRectangleBorder>(
RoundedRectangleBorder(
borderRadius: BorderRadius.circular(10.0),
side: const BorderSide(
color: Colors.indigo,
width: 2.0,
),
),
),
),
child: isLoading
? const SizedBox(
child: CircularProgressIndicator(
valueColor: AlwaysStoppedAnimation<Color>(
Colors.white)),
height: 15.0,
width: 15.0,
)
: const Text(
'Update Pet',
style:
TextStyle(fontSize: 17.0, color: Colors.white),
),
onPressed: () async {
if (nameController.text.isEmpty) {
nameController.text = widget.name;
}
if (tagController.text.isEmpty) {
tagController.text = widget.tags;
}
if (categoryController.text.isEmpty) {
categoryController.text = widget.category;
}
if (dropdownvalue == null) {
dropdownvalue = widget.status;
}
print('Pressed');
Map data = {
"id": random.nextInt(10000),
///random it integer
"name": nameController.text,
"category": {
"id": set_category_id(categoryController.text),
"name": categoryController.text,
},
"photoUrls": [base64Image],
"tags": set_tags(tags),
"status": dropdownvalue
};
var body = json.encode(data);
var response = await http.put(
Uri.parse(
"https://api.training.testifi.io/api/v3/pet"),
headers: {
"Content-Type": "application/json",
"Accept": "application/json"
},
body: body);
print(response.body);
print(response.statusCode);
if (response.statusCode == 201 ||
response.statusCode == 200) {
print('success');
Toast.show("Pet is successfully updated.", context);
Navigator.pushAndRemoveUntil(
context,
MaterialPageRoute(
builder: (BuildContext context) =>
PetStoreHomePage(LoggedIn: true),
),
(route) => false,
);
} else {
Toast.show(
"ERROR! Updating pet failed. Please try again.",
context);
}
}),
),
],
),
),
),
);
}
}
tags = widget.tags.where((e) => e != null && e != "").toList();
This line in build method will constantly take value from widget.tags and create a list of items thats not null and empty.
Please add this in initState.
Just initialize it
List<dynamic> tags = [];
PS: I tried initializing tags with tags=[] in my initState but I can't
remove any of the tags.
You need to add setState to rebuild the page.

Flutter -Widget Text, not updating when value change even with SetState

I have created a container. His child is a text.
When I tap on the container/text, it display a modal and a Picker.
Then, the user can select a value. Press the confirm button and my text widget should change to display the value selected by the user.
But in my case, it is not updating the value of the text widget. I have used that in the past and it was working very well. But here it is not and I do not see why. I am on this since 8:00. A little help would be appreciated. Many thanks.
int valuePickerUnitSelected =0;
String unitCount = '';
int unitCountInt;
String goal = "";
List <String> unitForHabits = ['Count', 'Minute(s)','Hour(s)','Gramme(s)', 'Pound(s)'];
class AddingHabitDetails extends StatefulWidget {
const AddingHabitDetails({Key key}) : super(key: key);
#override
_AddingHabitDetailsState createState() => _AddingHabitDetailsState();
}
class _AddingHabitDetailsState extends State<AddingHabitDetails> {
BuildContext get ctx => null;
#override
Widget build(BuildContext context) {
return Scaffold(
//drawer: new MyMenu(), //TODO a remettre
appBar: new AppBar(
title: new Text('Habits'),
),
body: Column(
children: [
titleZone('Name'),
textFieldHabits('Habit name', context),
titleZone('Goals'),
FlatButton(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
if (unitCount.length < 2 )...[
Container(
width: 65,
decoration: BoxDecoration(
border: Border.all(color: Colors.blue,
),
color: Colors.blue,
borderRadius: BorderRadius.all(Radius.circular(20))),
child:
Center(child: Text(
'Time', style: TextStyle(color: Colors.black,))))
]
else
...[
Container(
width: 65,
decoration: BoxDecoration(
border: Border.all(color: Colors.blue,),
color: Colors.blue,
borderRadius: BorderRadius.all(
Radius.circular(20))),
child: Center(
child: Text(
unitCount, style: TextStyle(color: Colors.black,))))
],
],
),
onPressed: () {
setState(() {
showModalBottomSheet(
context: context,
builder: (BuildContext context) {
return ShowPickerUnite(unitForHabits);
});
},
);
},
),
//ChipGoalV3(ctx),// ChipGoal(),
textFieldHabits('Goals', context),
titleZone('Frequency'),
textFieldHabits('Frequency', context),
titleZone('Time Range'),
titleZone('Reminder'),
titleZone('Habits Term'),
],
),
);
}
}
//########################################################################
class ShowPickerUnite extends StatefulWidget {
List<String> myListUnit;
ShowPickerUnite(this.myListUnit, {Key key}) : super(key: key);
#override
_ShowPickerUniteState createState() => _ShowPickerUniteState(
myListUnit);
}
class _ShowPickerUniteState extends State<ShowPickerUnite> {
List <String> myListUnit;
_ShowPickerUniteState(this.myListUnit);
#override
Widget build(BuildContext context) {
return Column(
mainAxisAlignment: MainAxisAlignment.end,
children: [
Container(
decoration: BoxDecoration(
color: Color(0xffffffff),
border: Border(
bottom: BorderSide(
color: Color(0xffffffff),
width: 0.0,
),
),
),
child: Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
CupertinoButton(
child: Text('Cancel'),
onPressed: () {
Navigator.of(context).pop();
},
padding: const EdgeInsets.symmetric(
horizontal: 16.0,
vertical: 5.0,
),
),
DefaultTextStyle(
style: TextStyle(
fontSize: 16.0,
color: Colors.black,
fontWeight: FontWeight.bold),
child: Text('Select what you want'),
),
// Text('Energy Needed', style: TextStyle(fontSize: 12.0, color: Colors.black),
// ),
CupertinoButton(
child: Text('Confirm'),
onPressed: () {
setState(() {
unitCount = unitForHabits[valuePickerUnitSelected];
print(unitCount);
});
Navigator.of(context).pop();
},
padding: const EdgeInsets.symmetric(
horizontal: 16.0,
vertical: 5.0,
),
),
],
),
),
Container(
//width: 360,
height: 200,
decoration:BoxDecoration(
borderRadius: BorderRadius.all(Radius.circular(15.0)),
),
child: CupertinoPicker(
backgroundColor: Colors.white ,
useMagnifier: true,
magnification: 1.3,
scrollController: FixedExtentScrollController(initialItem: 0),
itemExtent: 25,
children: [
for (String name in myListUnit)
Center(
child:Text(name)),
],
onSelectedItemChanged: (value) {
setState(() {
valuePickerUnitSelected = value;
// taskEnergy = myListEnergy[valuePickerEnergySelected];
// taskNewValue ['task_Energy'] = taskEnergy;
});
}))
]);
}
}
Widget inputNameHabit (){
return Padding(
padding: const EdgeInsets.all(8.0),
child: Text ('Name Habits',style: TextStyle(
fontSize: 25,
fontWeight: FontWeight.bold),),
);
}
Widget titleZone (String _titleName){
return Padding(
padding: const EdgeInsets.all(8.0),
child: Row(
children: [
Text ( _titleName,
style: TextStyle(
fontSize: 25,
fontWeight: FontWeight.bold),),
],
),
);
}
Widget textFieldHabits (String item,context){
return TextField(
decoration: InputDecoration(
hintText: item,
filled: true,
fillColor: Colors.grey[300],
border: OutlineInputBorder(
borderSide: BorderSide.none,
borderRadius: BorderRadius.circular(50)
),
),
onTap: (){
Navigator.push(context,
MaterialPageRoute(
builder: (context) => HabitGoalUnitSelection(), //TODO MODIFIER route selon source
),
);
},);
}
Wait for the dialog to finish and then call setState to update the UI.
Modify this way
onPressed: () async {
await showModalBottomSheet(
context: context,
builder: (BuildContext context) {
return ShowPickerUnite(unitForHabits);
});
setState(() {});

setState not updating the value in the screen using Flutter desktop

So I'm trying to update the value of the drop down list using the setState, but when I select a value from the list, the value on the screen won't be able to change
import 'package:demo_app_admin/Custom/custom_Font.dart';
import 'package:flutter/material.dart';
import '/Custom/Custom_Raised_Bottun.dart';
import '/Custom/Header.dart';
import '/Custom/inputField.dart';
class LoginView extends StatefulWidget {
#override
_LoginViewState createState() => _LoginViewState();
}
class _LoginViewState extends State<LoginView> {
#override
Widget build(BuildContext context) {
final GlobalKey<FormState> _formKey = GlobalKey<FormState>();
final isKeyboard = MediaQuery.of(context).viewInsets.bottom != 0;
String _dropdownvalue = "Global admin";
List<String> _items = <String> ["Global admin", "Institution admin"];
return Scaffold(
body: Container(
width: double.infinity,
decoration: BoxDecoration(
gradient: LinearGradient(begin: Alignment.topCenter, colors: [
Colors.teal[700]!,
Colors.teal[200]!,
Colors.teal[400]!
]),
),
child: Column(
children: <Widget>[
const SizedBox(
height: 80,
),
if (!isKeyboard)
Header(
padding: const EdgeInsets.all(20),
crossAxisAlignment: CrossAxisAlignment.start,
head: "Welcome",
headTextStyle:
const TextStyle(color: Colors.white, fontSize: 40),
sizedBoxHeight: 10,
subtitle: "Sign In to Your Admin Account",
subtitleTextStyle:
const TextStyle(color: Colors.white, fontSize: 18),
),
Expanded(
child: Container(
decoration: const BoxDecoration(
color: Colors.white,
borderRadius: BorderRadius.only(
topLeft: Radius.circular(60),
topRight: Radius.circular(60),
)),
child: Padding(
padding: const EdgeInsets.all(30),
child: SingleChildScrollView(
reverse: true,
padding: EdgeInsets.all(32),
child: Form(
key: _formKey,
child: Column(
children: <Widget>[
const SizedBox(
height: 40,
),
Container(
decoration: BoxDecoration(
color: Colors.white,
borderRadius: BorderRadius.circular(10)),
child: Column(
children: <Widget>[
InputField(
labelText: 'Email',
padding: EdgeInsets.all(10),
borderSide: BorderSide(color: Colors.grey),
hintText: "Enter your email",
color: Colors.grey,
inputBorder: InputBorder.none,
obscureText: false,
enableSuggestion: true,
autoCorrect: true,
onSaved: (value) {},
// (value){controller.email = value!;},
validator: (value) {
if (value == null) {
print("ERROR");
}
},
),
InputField(
labelText: 'Password',
padding: EdgeInsets.all(10),
borderSide: BorderSide(color: Colors.grey),
hintText: "Enter your password",
color: Colors.grey,
inputBorder: InputBorder.none,
obscureText: true,
enableSuggestion: false,
autoCorrect: false,
onSaved: (value) {},
// (value){ controller.password = value!;},
validator: (value) {
if (value == null) {
print("ERROR");
}
},
),
],
),
),
const SizedBox(
height: 40,
),
here is the issue
DropdownButton<String>(
value: _dropdownvalue,
icon: Icon(Icons.keyboard_arrow_down),
items: _items.map((String _items) {
return DropdownMenuItem<String>(
value: _items,
child: CustomFont(text: _items),
);
}).toList(),
onChanged: (value) {
setState(() => _dropdownvalue = value!);
}),
const SizedBox(
height: 40,
),
CustomRaisedButton(
width: 200,
height: 50.0,
margin: const EdgeInsets.symmetric(horizontal: 50),
color: Colors.teal.shade500,
borderRadius: BorderRadius.circular(10),
text: "LOGIN",
textColor: Colors.white,
fontSize: 17,
fontWeight: FontWeight.bold,
function: () {}
// {
// _formKey.currentState?.save();
// if(_formKey.currentState?.validate() !=null){
// controller.signInWithEmailAndPassword();
// }
// },
),
SizedBox(
height: 10,
),
],
),
),
),
),
))
],
),
),
);
}
}
The issue is here, you are declaring variables inside build. Therefore, variables get reset to default value on every build. Means setState.
Declare variables outside the build method.
class _LoginViewState extends State<LoginView> {
final GlobalKey<FormState> _formKey = GlobalKey<FormState>();
String _dropdownvalue = "Global admin";
List<String> _items = <String>["Global admin", "Institution admin"];
#override
Widget build(BuildContext context) {
final isKeyboard = MediaQuery.of(context).viewInsets.bottom != 0;
return Scaffold(
More about StatefulWidget.

I want to implement OTP verification screen without any package

I want to implement OTP verification screen without any package.
when i entered the number it should move to next input field
I m using this code in my current project take a refrence this will help
class Otp extends StatefulWidget {
final String? phnNumber;
final String ? code;
String? from;
Otp({Key ?key, this.phnNumber, this.from, this.code}) : super(key:
key);
#override
_OtpState createState() => _OtpState();
}
class _OtpState extends State<Otp> {
double ? height ;
double ? width;
TextEditingController ? contrller1;
TextEditingController ? contrller2;
TextEditingController ? contrller3;
TextEditingController ? contrller4;
SendOtpRequest resend = SendOtpRequest();
SharedPreferences ? prefs;
getSharedPreferences () async
{
prefs = await SharedPreferences.getInstance();
}
String Code = "";
#override
void initState() {
// TODO: implement initState
super.initState();
contrller1 = TextEditingController();
contrller2 = TextEditingController();
contrller3 = TextEditingController();
contrller4 = TextEditingController();
getSharedPreferences();
}
#override
Widget build(BuildContext context) {
height= MediaQuery.of(context).size.height;
width = MediaQuery.of(context).size.height;
final verifyprovider = Provider.of<PostDataProvider>(context);
return Scaffold(
resizeToAvoidBottomInset: false,
appBar: AppBar(
toolbarHeight:height! * 0.07802345,
titleSpacing: 0,
backgroundColor: HexColor("#18263d"),
automaticallyImplyLeading: false,
leading: Padding(
padding: const EdgeInsets.only(left: 8.0,),
child: GestureDetector(
onTap: () {
Navigator.pop(context);
},
child: Container(
color: Colors.transparent,
child: Image.asset("assets/images/back_ic-1.png")),
),
),
// SizedBox(width: width!*0.001234,),
title:Row(
mainAxisAlignment: MainAxisAlignment.start,
children: [
Container(
height: height!/15,
width: height!/15,
decoration: BoxDecoration(
shape: BoxShape.circle,
border: Border.all(
width: 2,
color:HexColor("#fc4f00"),
)),
child: Padding(
padding: const EdgeInsets.all(1.0),
child: Container(
height: height!/11,
width: height!/11,
decoration: BoxDecoration(
image: const DecorationImage(
image:
AssetImage("assets/images/home_logo.png"),
fit: BoxFit.fill
),
shape: BoxShape.circle,
border: Border.all(
width: 1,
color:HexColor("#fc4f00"),
)),
),
),
),
SizedBox(width: width! * 0.04234,),
Padding(
padding: const EdgeInsets.only(bottom: 8.0),
child: Text("Verification",
style: GoogleFonts.oswald(fontWeight: FontWeight.bold,
color: Colors.white,
fontSize: width! * 0.03345
),),
),
],
) ,
),
body: SafeArea(
child: Padding(
padding: EdgeInsets.symmetric(vertical: 24, horizontal: 32),
child: Column(
children: [
Text("We have send verification code on your mobile number",
style: GoogleFonts.oswald(fontStyle: FontStyle.normal,
fontSize: width!*0.0234,
color: HexColor("#8b8b8b")),
),
SizedBox(height: height!/38,),
Column(
children: [
Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
_textFieldOTP(first: true, last: false,controllerr:
contrller1),
_textFieldOTP(first: false, last: false,controllerr:
contrller2),
_textFieldOTP(first: false, last: false,controllerr:
contrller3),
_textFieldOTP(first: false, last: true, controllerr:
contrller4),
],
),
Padding(
padding: const EdgeInsets.all(8.0),
child: InkWell(
onTap:() {
resend.phoneNumber= widget.phnNumber;
resend.countryCode = widget.code;
verifyprovider.resendOtp(context,
jsonEncode(resend));
},
child: Text("Resend OTP?",
style: GoogleFonts.oswald(fontStyle:
FontStyle.normal,
fontSize: width!*0.0234,
color: HexColor("#fc4f00")),
),
),
),
SizedBox(height: height!/28,),
GestureDetector(
onTap: (){
if(contrller1!.text.isNotEmpty&&
contrller2!.text.isNotEmpty&&contrller3!.
text.isNotEmpty&&contrller4!.text.isNotEmpty){
verifyOtpRequest verify = verifyOtpRequest();
verify.phoneNumber = widget.phnNumber;
verify.otp=
contrller1!.text+contrller2!.
text+contrller3!.text+contrller4!.text;
verifyprovider.otpVerification(context,
jsonEncode(verify), widget.from);
}else{
CommonUtils.showToast(msg: "Please fill all the
fields ");
}
},
child: Container(
height: height!/18,
width: width,
decoration: BoxDecoration(
color: HexColor("#fc4f00"),
borderRadius: BorderRadius.circular(10)
),
child: Center(
child: Text("Verify",style: TextStyle(
color: Colors.white,
fontSize: width!*0.02345
),),
)
),
),
],
),
],
),
),
),
);
}
Widget _textFieldOTP({bool ? first, last,
TextEditingController ?
controllerr}) {
return Container(
height:height!/12 ,
child: AspectRatio(
aspectRatio: 1.0,
child: TextField(
controller: controllerr,
autofocus: true,
onChanged: (value) {
if (value.length == 1 && last == false) {
FocusScope.of(context).nextFocus();
}
if (value.length == 0 && first == false) {
FocusScope.of(context).previousFocus();
}
},
showCursor: false,
readOnly: false,
textAlign: TextAlign.center,
style: TextStyle(fontSize: 24, fontWeight: FontWeight.bold),
keyboardType: TextInputType.number,
maxLength: 1,
decoration: InputDecoration(
counter: Offstage(),
enabledBorder: OutlineInputBorder(
borderSide: BorderSide(width: 2, color: Colors.black54),
borderRadius: BorderRadius.circular(12)),
focusedBorder: OutlineInputBorder(
borderSide: BorderSide(width: 2, color: Colors.black54),
borderRadius: BorderRadius.circular(12)),
),
),
),
);
}
}
When the length of the input data reaches one, you will have to change the text field focus node.
For Example
If you are in the first field, and you enter a number field one focus should be lost, and field two should be in focus. This can be done, by requestFocus.
This article will of help for you: Flutter Focus

Dart Null safety error : Null check operator used on a null value [duplicate]

This question already has answers here:
Null check operator used on a null value
(12 answers)
Closed last year.
I got this error, i understood it but i don't know how to fix it
This error occurs when I try to use the variables of the profilPicker class.
class MyDrawerPages extends StatefulWidget {
final ValueChanged<DrawerItem> onSelectedItem;
final VoidCallback? onClick;
const MyDrawerPages({
Key? key,
required this.onSelectedItem,
this.onClick,
}) : super(key: key);
#override
_MyDrawerPagesState createState() => _MyDrawerPagesState();
}
class _MyDrawerPagesState extends State<MyDrawerPages> {
final signUpKey = GlobalKey<_ProfilPickerState>();
var stringName = '';
var stringTeam = '';
#override
Widget build(BuildContext context) {
final name = signUpKey.currentState!.name;
final team = signUpKey.currentState!.team;
final bool isSignin = signUpKey.currentState!.isSignin;
return Scaffold(
body: Container(
color: const Color(0xFFE26A2C),
child: Column(
children: [
Padding(
key: signUpKey,
padding: const EdgeInsets.only(top: 20, bottom: 10),
child: ListTile(
leading: GestureDetector(
onTap: () {
Navigator.pushNamed(context, '/profil_picker');
},
child: const CircleAvatar(
backgroundColor: Color(0xFF463E3E),
child: Icon(
Icons.person,
size: 40,
color: Colors.white,
),
radius: 22,
),
),
title: Text(
isSignin ? name.toString().toUpperCase() : stringName,
style: const TextStyle(color: Colors.white),
),
subtitle: Text(
isSignin
? team.toString()
: stringTeam,
style: const TextStyle(color: Colors.white)),
),
),
SingleChildScrollView(
child: Column(children: [listTileDrawer(context)]),
),
],
),
),
);
}
here is the ProfilPicker class
class _ProfilPickerState extends State<ProfilPicker> {
bool visible = false;
File? image;
late String name;
late String team;
TextEditingController nameController = TextEditingController();
TextEditingController teamController = TextEditingController();
var isSignin = true;
Future pickeImage(ImageSource source) async {
final image = await ImagePicker().pickImage(source: source);
if (image == null) return;
final saveImage = await saveImagepermanently(image.path);
try {
setState(() {
this.image = saveImage;
});
} on Exception catch (e) {
// ignore: avoid_print
print('failed to pick image $e');
}
}
bool signUp = true;
#override
Widget build(BuildContext context) {
return SafeArea(
child: Scaffold(
appBar: AppBar(
iconTheme: const IconThemeData(color: Colors.black),
backgroundColor: Colors.transparent,
elevation: 0,
),
backgroundColor: const Color(0xFFFFFFFF),
body: Center(
child: SingleChildScrollView(
child: Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: [
Column(
children: [
Container(
height: 150,
width: 150,
decoration: BoxDecoration(
color: Colors.blueGrey[200],
borderRadius: BorderRadius.circular(200)),
child: image != null
? ClipOval(
child: Image.file(
image!,
width: 150,
height: 150,
fit: BoxFit.cover,
),
)
: const Icon(
Icons.add_a_photo,
size: 30,
),
),
],
),
const SizedBox(
height: 100,
),
signUp
? Column(
children: [
Card(
margin:
const EdgeInsets.symmetric(horizontal: 40),
child: ListTile(
onTap: () {
setState(() {
pickeImage(ImageSource.gallery);
signUp = false;
});
},
leading: const Icon(Icons.image_outlined),
title: const Text("Gallery"),
),
color: Colors.blue[100]),
const SizedBox(
height: 10,
),
Card(
color: Colors.blue[100],
margin: const EdgeInsets.symmetric(horizontal: 40),
child: ListTile(
onTap: () {
setState(() {
pickeImage(ImageSource.camera);
signUp = false;
});
},
leading: const Icon(Icons.camera),
title: const Text("Camera"),
),
),
],
)
: Column(
children: [
_listTileBuilder(),
const SizedBox(
height: 30,
)
],
)
],
),
),
),
),
);
}
_listTileBuilder() {
return SingleChildScrollView(
child: Wrap(
crossAxisAlignment: WrapCrossAlignment.center,
children: [
Padding(
padding: const EdgeInsets.all(10),
child: Column(
children: [
Container(
alignment: Alignment.topLeft,
padding: const EdgeInsets.fromLTRB(0, 10, 0, 4),
child: const Text('Profil')),
const Padding(
padding: EdgeInsets.only(right: 50),
child: Divider(
indent: 4,
color: Colors.black,
),
),
],
),
),
Padding(
padding: const EdgeInsets.all(10),
child: Column(
children: [
TextField(
controller: nameController,
maxLines: 1,
keyboardType: TextInputType.name,
style: const TextStyle(fontSize: 14),
decoration: InputDecoration(
filled: true,
fillColor: Colors.blue[100],
border: const OutlineInputBorder(
borderSide: BorderSide.none,
borderRadius: BorderRadius.all(Radius.circular(10))),
label: const Text('name',
style: TextStyle(fontStyle: FontStyle.italic)),
),
),
const Padding(padding: EdgeInsets.all(4)),
TextField(
controller: teamController,
maxLines: 1,
keyboardType: TextInputType.name,
style: const TextStyle(fontSize: 14),
decoration: InputDecoration(
filled: true,
fillColor: Colors.blue[100],
border: const OutlineInputBorder(
borderSide: BorderSide.none,
borderRadius: BorderRadius.all(Radius.circular(10))),
label: const Text(
'Team',
style: TextStyle(fontStyle: FontStyle.italic),
),
),
)
],
),
),
const Padding(
padding: EdgeInsets.all(20),
),
Row(
mainAxisAlignment: MainAxisAlignment.end,
children: [
TextButton(
onPressed: () {
// Navigator.pop();
},
child: Text(
'cancel'.toUpperCase(),
style: const TextStyle(fontWeight: FontWeight.bold),
)),
TextButton(
onPressed: () {
setState(() {
isSignin;
name = nameController.text;
team = teamController.text;
});
},
child: Text('ok'.toUpperCase(),
style: const TextStyle(fontWeight: FontWeight.bold)))
],
)
],
),
);
}
}
I don't have more details
thanks in advance!
I am listening to you,
be indulgent I am a beginner thank you!
error code
════════ Exception caught by widgets library ═══════════════════════════════════
The following _CastError was thrown building MyDrawerPages(dirty, state: _MyDrawerPagesState#a6f02):
Null check operator used on a null value
the problem is here
final name = signUpKey.currentState!.name;
final team = signUpKey.currentState!.team;
you're trying to access name and team where they are supposed to be not null, because they are marked late, but you don't assign them a value until you click on the ok button, which in the build method above they are null.
so you should make them nullable and check wether they are null or not instead. like this:
String? name;
String? team;
...
final name = signUpKey.currentState!.name ?? '';
final team = signUpKey.currentState!.team ?? '';
try this and tell me if it worked!
This error is caused When Null check operator (!) is used on variable with a null value.
You must track all the variable and find this null value or use other operator to solve the problem or check if the value is not null.
You can use ?? operator and give an alternative value if null like this
Text(name ?? 'Not Found')
You can find every thing you need about null aware operators in this article Go To Article