Boolean expression must not be null when saving form flutter - flutter

am trying to save the formState in the elevated button below but, the validation goes through but when it starts saving I get this error : 'boolean expression must not be null', and I don't have any boolean to save.
I tried adding onSaved inside the dropDowns but still the same issue, anyone can help please?
class OfferPriceAndUsageWidget extends StatelessWidget {
final _formKey = GlobalKey<FormState>();
#override
Widget build(BuildContext context) {
final size = MediaQuery.of(context).size;
return Consumer<AddOfferProvider>(
builder: (context, provider, snapshot) {
return Form(
key: _formKey,
child: Column(
children: [
CenteredSubtitleWidget(label: 'Prix et usage'),
LayoutBuilder(
builder: (context, constraints) {
final List<bool> searchType = [
provider.isBuy(),
!provider.isBuy(),
];
return ToggleButtons(
constraints: BoxConstraints.expand(
width: size.width / 2.1,
height: 50,
),
isSelected: searchType,
borderColor: Colors.teal.shade700,
borderWidth: 0,
borderRadius: BorderRadius.circular(10),
children: [
Text("Vente"),
Text("Location"),
],
onPressed: (index) {
switch (index) {
case 0:
provider.setBuy();
break;
case 1:
provider.setRent();
break;
default:
print('Error selecting the objectif.');
break;
}
},
);
},
),
verticalSpacer,
DropdownButtonFormField(
decoration: buildDropDownInputDecoration(hint: 'Usage'),
hint: Text("Usage"),
items: generateTerrainUsage(),
value: provider.offerInformation['usage'],
onChanged: (value) {
provider.setUsage(value);
},
),
verticalSpacer,
Row(
children: [
Expanded(
child: TextFormField(
initialValue: '20',
enabled: !provider.offerInformation['hidePrice'],
keyboardType: TextInputType.number,
onSaved: (value) {
if (provider.offerInformation['ispricePerMeter'])
provider.offerInformation['pricePerMeter'] = value;
provider.offerInformation['price'] = value;
},
validator: requiredElementValidator,
decoration: buildFormInputDecoration(
label: 'Prix (DT)',
),
),
),
horizontalSpacer,
Expanded(
child: TextFormField(
onSaved: (value) {
provider.offerInformation['surface'] = value;
},
validator: requiredElementValidator,
keyboardType: TextInputType.number,
decoration: buildFormInputDecoration(
label: 'Surface (m²)',
),
),
),
],
),
Row(
mainAxisAlignment: MainAxisAlignment.start,
children: [
Checkbox(
value: provider.offerInformation['hidePrice'],
onChanged: provider.toggleHidePrice,
),
GestureDetector(
onTap: () {
return provider.toggleHidePrice(
!provider.offerInformation['hidePrice'],
);
},
child: Text("Cacher le prix"),
),
if (!provider.offerInformation['hidePrice']) ...[
Checkbox(
value: provider.offerInformation['isPricePerMeter'],
onChanged: provider.togglePricePerMeter,
),
GestureDetector(
onTap: () {
return provider.togglePricePerMeter(
!provider.offerInformation['isPricePerMeter'],
);
},
child: Text("Prix par m²"),
),
]
],
),
Row(
children: [
Expanded(
child: ElevatedButton(
onPressed: () {
try {
if (_formKey.currentState.validate())
_formKey.currentState.save();
// print(provider.offerInformation);
} catch (e) {
print(e);
print(provider.offerInformation);
}
},
child: Text("Valider"),
),
)
],
),
],
),
);
},
);
}
}

About the currentState getter:
The current state is null if (1) there is no widget in the tree that matches this global key, (2) that widget is not a [StatefulWidget], or the associated [State] object is not a subtype of T.
Switch to a StatefulWidget and add a null check to currentState
_formKey.currentState!.validate()
_formKey.currentState!.save()

Related

How set form validation in widget flutter

I'm working on flutter project .I have a revision form validator that is not working as expected. When I leave the TextFormField empty the validator doesn't show me anything. I want to stay on the revision form until I enter the values.
thanks in advance
my code :
class Revision extends StatefulWidget {
}
class _RevisionState extends State<Revision> with TickerProviderStateMixin {
final GlobalKey<FormState> _formKey = GlobalKey<FormState>();
RevisionApi revisionApi = RevisionApi();
TextEditingController _Kilometrage_revisionController =
TextEditingController();
_showAddDialog() async {
await showDialog(
context: context,
builder: (context) => AlertDialog(
backgroundColor: Colors.white,
title: Text("Ajouter un évènement"),
content: StatefulBuilder(builder: (
BuildContext context,
StateSetter setState,
) {
return SingleChildScrollView(
child: Form(
key: _formKey,
child: Column(
mainAxisSize: MainAxisSize.min,
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Row(children: [
Expanded(
child: DropdownButtonFormField(
decoration: InputDecoration(
hoverColor: Colors.white,
//contentPadding: EdgeInsets.only(left: 10, right: 15, top: 15),
labelText: 'Type',
alignLabelWithHint: true,
labelStyle: TextStyle(
color: kPrimaryColor,
),
enabledBorder: UnderlineInputBorder(
borderSide: BorderSide(color: Colors.grey),
),
),
dropdownColor: Colors.white,
value: status,
items: <DropdownMenuItem>[
DropdownMenuItem(
// value: 'videnge',
value: 0,
child: InkWell(
child: Text('videnge'),
hoverColor: Colors.indigo,
),
),
DropdownMenuItem(
// value: 'visite technique',
value: 1,
child: Text('visite technique'),
),
DropdownMenuItem(
// value: 'assurance véhicule',
value: 2,
child: Text('assurance véhicule'),
),
DropdownMenuItem(
// value: 'autre',
value: 3,
child: Text('autre'),
),
],
onChanged: (value) {
setState(() {
status = value;
});
},
)),
]),
if (status == 1) visiTechniqueDropdown(),
]),
));
}),
actions: <Widget>[
TextButton(
child: Text(
"Enregistrer",
style: TextStyle(
color: Colors.red, fontWeight: FontWeight.bold),
),
onPressed: () {
if (status == null) return;
setState(() {
if (_events[_controller.selectedDay] != null) {
_events[_controller.selectedDay].add(status);
} else {
_events[_controller.selectedDay] = [status];
}
prefs.setString(
"events", json.encode(encodeMap(_events)));
status;
setRevision();
_KilometrageController.clear();
_eventController.clear();
_EmplacementController.clear();
_DateController.clear();
_repeat_revisionController.clear();
_revision_agenceController.clear();
_Kilometrage_revisionController.clear();
Navigator.of(context).pop();
// Navigator.pop(context);
});
},
),
new TextButton(
onPressed: () {
Navigator.of(context).pop();
},
child: const Text('Retour'),
),
],
));
}
void setRevision() async {
print("hello");
if (_formKey.currentState.validate()) {
String kilometrage_pour_vidange = _KilometrageController.text;
String revision_type = status.toString();
String revision_title = _eventController.text;
String revision_location = _EmplacementController.text;
String revision_date = _DateController.text;
String repeat_revision = _repeat_revisionController.text;
String revision_agence = _revision_agenceController.text;
String kilometrage_revision = _Kilometrage_revisionController.text;
revisionApi
.setRevision(
revision_type,
revision_title,
revision_date,
revision_location,
kilometrage_pour_vidange,
repeat_revision,
revision_agence,
kilometrage_revision,
)
.then((data) {
if (data != null) {
Navigator.pop(context);
Navigator.of(context).pop();
Navigator.push(
context, MaterialPageRoute(builder: (context) => Revision()));
}
ScaffoldMessenger.of(context)
.showSnackBar(SnackBar(content: Text(data)));
}).catchError((error) {
ScaffoldMessenger.of(context)
.showSnackBar(SnackBar(content: Text(error.toString())));
});
setState(() {});
}
}
Widget visiTechniqueDropdown() {
return Column(mainAxisSize: MainAxisSize.min, children: [
Row(
children: [
Flexible(
child: TextFormField(
onFieldSubmitted: (_) => FocusScope.of(context).nextFocus(),
validator: (value) {
if (value.isEmpty) {
return 'Password is required';
}
return null;
},
controller: _DateController,
cursorColor: kPrimaryColor,
decoration: InputDecoration(
labelText: 'Date',
alignLabelWithHint: true,
labelStyle: TextStyle(
color: kPrimaryColor,
),
enabledBorder: UnderlineInputBorder(
borderSide: BorderSide(color: Colors.grey),
How i can set the validator correctly ?
This is for you. Thanks and enjoy
// Create a corresponding State class.
// This class holds data related to the form.
class MyFormState extends State<MyForm> {
// Create a global key that uniquely identifies the Form widget
// and allows validation of the form.
//
// Note: This is a GlobalKey<FormState>,
// not a GlobalKey<MyFormState>.
final _formKey = GlobalKey<FormState>();
#override
Widget build(BuildContext context) {
// Build a Form widget using the _formKey created above.
return Form(
key: _formKey,
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
TextFormField(
// The validator receives the text that the user has entered.
validator: (value) {
if (value == null || value.isEmpty) {
return 'Please enter some text';
}
return null;
},
),
Padding(
padding: const EdgeInsets.symmetric(vertical: 16.0),
child: ElevatedButton(
onPressed: () {
// Validate returns true if the form is valid, or false otherwise.
if (_formKey.currentState!.validate()) {
// If the form is valid, display a snackbar. In the real world,
// you'd often call a server or save the information in a database.
// sendData();
ScaffoldMessenger.of(context)
.showSnackBar(SnackBar(content: Text('Processing Data')));
}
},
child: Text('Submit'),
),
),
],
),
);
}
}

Is there any way I can reset the dynamic fields I added into a form to their previous state if user doesn't make any changes (Presses back)?

I'm trying to create a dynamic form so I used the idea of using a listview builder to create it. I was able to successfully create it but I faced that I cannot discard changes made to the form by popping it off after editing it. The two textFormField Job name and rate per hour were able to discard changes as they were using onsaved but on the checkbox I can't do that as it has onChanged which wraps setstate to change its state.
You can take a look at the video at this link to see how it functions as of now - https://vimeo.com/523847256
As you can see that it is retaining the data even after popping the page and coming back which I don't want it to. I'm looking for a way to prevent that and make the form the same as before if the user didn't press save.
I have tried to reassign the variables() in onpressed of back button but that didn't work. I also tried push replacement to the same page to reset it but that also didn't work. I think the cuprit here is the sublist and the initialValueTextFormField and initialValueCheckbox which are used declared under ListView.builder but I don't know how to fix that without affecting the dynamic list functionality.
class EditJobPage extends StatefulWidget {
const EditJobPage({Key key, this.job}) : super(key: key);
final Job job;
static Future<void> show(BuildContext context, {Job job}) async {
await Navigator.of(context, rootNavigator: true).pushNamed(
AppRoutes.editJobPage,
arguments: job,
);
}
#override
_EditJobPageState createState() => _EditJobPageState();
}
class _EditJobPageState extends State<EditJobPage> {
final _formKey = GlobalKey<FormState>();
String _name;
int _ratePerHour;
List<dynamic> _subList = [];
Set newSet = Set('', false);
#override
void initState() {
super.initState();
if (widget.job != null) {
_name = widget.job?.name;
_ratePerHour = widget.job?.ratePerHour;
_subList = widget.job?.subList;
}
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
elevation: 2.0,
title: Text(widget.job == null ? 'New Job' : 'Edit Job'),
leading: IconButton(
icon: Icon(Icons.clear),
onPressed: () {
Navigator.of(context).pop();
},
),
actions: <Widget>[
FlatButton(
child: const Text(
'Save',
style: TextStyle(fontSize: 18, color: Colors.white),
),
onPressed: () => _submit(),
),
],
),
body: _buildContents(),
backgroundColor: Colors.grey[200],
);
}
Widget _buildContents() {
return SingleChildScrollView(
child: Padding(
padding: const EdgeInsets.all(16.0),
child: Card(
child: Padding(
padding: const EdgeInsets.all(16.0),
child: _buildForm(),
),
),
),
);
}
Widget _buildForm() {
return Form(
key: _formKey,
child: Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: _buildFormChildren(),
),
);
}
List<Widget> _buildFormChildren() {
print(_subList);
return [
TextFormField(
decoration: const InputDecoration(labelText: 'Job name'),
keyboardAppearance: Brightness.light,
initialValue: _name,
validator: (value) =>
(value ?? '').isNotEmpty ? null : 'Name can\'t be empty',
onChanged: (value) {
setState(() {
_name = value;
});
},
),
TextFormField(
decoration: const InputDecoration(labelText: 'Rate per hour'),
keyboardAppearance: Brightness.light,
initialValue: _ratePerHour != null ? '$_ratePerHour' : null,
keyboardType: const TextInputType.numberWithOptions(
signed: false,
decimal: false,
),
onChanged: (value) {
setState(() {
_ratePerHour = int.tryParse(value ?? '') ?? 0;
});
},
),
Column(
children: <Widget>[
ListView.builder(
shrinkWrap: true,
itemCount: _subList?.length ?? 0,
itemBuilder: (context, index) {
String initialValueTextFormField =
_subList[index].subListTitle.toString();
bool initialValueCheckbox = _subList[index].subListStatus;
return Row(
children: [
Checkbox(
value: initialValueCheckbox,
onChanged: (bool newValue) {
setState(
() {
initialValueCheckbox = newValue;
_subList.removeAt(index);
_subList.insert(
index,
Set(initialValueTextFormField,
initialValueCheckbox));
},
);
},
),
Expanded(
child: TextFormField(
minLines: 1,
maxLines: 1,
initialValue: initialValueTextFormField,
autofocus: false,
textAlign: TextAlign.left,
onChanged: (title) {
setState(() {
initialValueTextFormField = title;
_subList.removeAt(index);
_subList.insert(
index,
Set(initialValueTextFormField,
initialValueCheckbox));
});
},
decoration: InputDecoration(
border: UnderlineInputBorder(),
labelStyle: TextStyle(
color: Colors.black,
fontWeight: FontWeight.w600,
),
filled: true,
hintText: 'Write sub List here',
),
),
),
],
);
},
),
TextButton(
onPressed: () {
setState(() {
_subList.add(newSet);
});
},
child: Row(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Icon(Icons.add),
Text('Add Sub Lists'),
],
),
),
],
),
];
}
void _submit() {
final isValid = _formKey.currentState.validate();
if (!isValid) {
return;
} else {
final database = context.read<FirestoreDatabase>(databaseProvider);
final id = widget.job?.id ?? documentIdFromCurrentDate();
final job = Job(
id: id,
name: _name ?? '',
ratePerHour: _ratePerHour ?? 0,
subList: _subList);
database.setJob(job);
Navigator.of(context).pop();
}
}
}
And this is the link to the full repository of the whole flutter app in case you want to look at any other part:- https://github.com/brightseagit/dynamic_forms . Thank you.
Note - This is the edited code of this repo - https://github.com/bizz84/starter_architecture_flutter_firebase.
When assigning the list we need to use _subList = List.from(widget.job.subList) instead of _subList = widget.job.subList.
Otherwise, the changes made in _subList will also be made in job.subList .

Flutter: How to keep list data inside table even after switching screens back and forth?

I have a form (second screen) which is used for CRUD. When i add data, it is saved to list view as you can see on the table.
The list view is passed to (first screen) where i can iterate and see the list data with updated content.
However, when i click on go to second screen, the list view data disappears. The given 3 lists are hard coded for testing purpose.
Now, my question is that, How can i keep the data in the table and not disappear, even if i change screen back and forth multiple times. My code is as below: -
**
Main.dart File
**
class MyApp extends StatefulWidget {
#override
_MyAppState createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> {
String _userInformation = 'No information yet';
void languageInformation() async {
final language = await Navigator.push(
context,
MaterialPageRoute(
builder: (context) => Episode5(),
),
);
updateLanguageInformation(language);
}
void updateLanguageInformation(List<User> userList) {
for (var i = 0; i <= userList.length; i++) {
for (var name in userList) {
print("Name: " + name.name[i] + " Email: " + name.email[i]);
}
}
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("Testing List View Data From second page to first page"),
),
body: Column(
children: <Widget>[
Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: <Widget>[
Text(_userInformation),
],
),
SizedBox(
height: 10.0,
),
ElevatedButton(
onPressed: () {
languageInformation();
},
child: Text("Go to Form"),
),
],
),
);
}
}
2. Model.dart File:
class User {
String name;
String email;
User({this.name, this.email});
}
3. Episode5 File
class Episode5 extends StatefulWidget {
#override
_Episode5State createState() => _Episode5State();
}
class _Episode5State extends State<Episode5> {
TextEditingController nameController = TextEditingController();
TextEditingController emailController = TextEditingController();
final form = GlobalKey<FormState>();
static var _focusNode = new FocusNode();
bool update = false;
int currentIndex = 0;
List<User> userList = [
User(name: "a", email: "a"),
User(name: "d", email: "b"),
User(name: "c", email: "c"),
];
#override
Widget build(BuildContext context) {
Widget bodyData() => DataTable(
onSelectAll: (b) {},
sortColumnIndex: 0,
sortAscending: true,
columns: <DataColumn>[
DataColumn(label: Text("Name"), tooltip: "To Display name"),
DataColumn(label: Text("Email"), tooltip: "To Display Email"),
DataColumn(label: Text("Update"), tooltip: "Update data"),
],
rows: userList
.map(
(user) => DataRow(
cells: [
DataCell(
Text(user.name),
),
DataCell(
Text(user.email),
),
DataCell(
IconButton(
onPressed: () {
currentIndex = userList.indexOf(user);
_updateTextControllers(user); // new function here
},
icon: Icon(
Icons.edit,
color: Colors.black,
),
),
),
],
),
)
.toList(),
);
return Scaffold(
appBar: AppBar(
title: Text("Data add to List Table using Form"),
),
body: Container(
child: Column(
children: <Widget>[
bodyData(),
Padding(
padding: EdgeInsets.all(10.0),
child: Form(
key: form,
child: Container(
child: Column(
children: <Widget>[
TextFormField(
controller: nameController,
focusNode: _focusNode,
keyboardType: TextInputType.text,
autocorrect: false,
maxLines: 1,
validator: (value) {
if (value.isEmpty) {
return 'This field is required';
}
return null;
},
decoration: new InputDecoration(
labelText: 'Name',
hintText: 'Name',
labelStyle: new TextStyle(
decorationStyle: TextDecorationStyle.solid),
),
),
SizedBox(
height: 10,
),
TextFormField(
controller: emailController,
keyboardType: TextInputType.text,
autocorrect: false,
maxLines: 1,
validator: (value) {
if (value.isEmpty) {
return 'This field is required';
}
return null;
},
decoration: new InputDecoration(
labelText: 'Email',
hintText: 'Email',
labelStyle: new TextStyle(
decorationStyle: TextDecorationStyle.solid)),
),
SizedBox(
height: 10,
),
Column(
children: <Widget>[
Center(
child: Row(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Row(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
TextButton(
child: Text("Add"),
onPressed: () {
form.currentState.save();
addUserToList(
nameController.text,
emailController.text,
);
},
),
TextButton(
child: Text("Update"),
onPressed: () {
form.currentState.save();
updateForm();
},
),
],
),
Row(
crossAxisAlignment: CrossAxisAlignment.end,
mainAxisAlignment: MainAxisAlignment.end,
children: <Widget>[
ElevatedButton(
child: Text("Save and Exit"),
onPressed: () {
form.currentState.save();
addUserToList(
nameController.text,
emailController.text,
);
Navigator.pop(context, userList);
},
),
],
),
],
),
),
],
),
],
),
),
),
),
],
),
),
);
}
void updateForm() {
setState(() {
User user = User(name: nameController.text, email: emailController.text);
userList[currentIndex] = user;
});
}
void _updateTextControllers(User user) {
setState(() {
nameController.text = user.name;
emailController.text = user.email;
});
}
void addUserToList(name, email) {
setState(() {
userList.add(User(name: name, email: email));
});
}
}
So instead of passing data back and forth between pages, its better to implement a state management solution so that you can access your data from anywhere in the app, without having to manually pass anything.
It can be done with any state management solution, here's how you could do it with GetX.
I took all your variables and methods and put them in a Getx class. Anything in this class will be accessible from anywhere in the app. I got rid of setState because that's no longer how things will be updated.
class FormController extends GetxController {
TextEditingController nameController = TextEditingController();
TextEditingController emailController = TextEditingController();
int currentIndex = 0;
List<User> userList = [
User(name: "a", email: "a"),
User(name: "d", email: "b"),
User(name: "c", email: "c"),
];
void updateForm() {
User user = User(name: nameController.text, email: emailController.text);
userList[currentIndex] = user;
update();
}
void updateTextControllers(User user) {
nameController.text = user.name;
emailController.text = user.email;
update();
}
void addUserToList(name, email) {
userList.add(User(name: name, email: email));
update();
}
void updateLanguageInformation() {
// for (var i = 0; i <= userList.length; i++) { // ** don't need nested for loop here **
for (var user in userList) {
print("Name: " + user.name + " Email: " + user.email);
}
// }
}
}
GetX controller can be initialized anywhere before you try to use it, but lets do it main.
void main() {
Get.put(FormController()); // controller init
runApp(MyApp());
}
Here's your page, we find the controller and now all variables and methods come from that controller.
class Episode5 extends StatefulWidget {
#override
_Episode5State createState() => _Episode5State();
}
class _Episode5State extends State<Episode5> {
final form = GlobalKey<FormState>();
static var _focusNode = new FocusNode();
// finding same instance if initialized controller
final controller = Get.find<FormController>();
#override
Widget build(BuildContext context) {
Widget bodyData() => DataTable(
onSelectAll: (b) {},
sortColumnIndex: 0,
sortAscending: true,
columns: <DataColumn>[
DataColumn(label: Text("Name"), tooltip: "To Display name"),
DataColumn(label: Text("Email"), tooltip: "To Display Email"),
DataColumn(label: Text("Update"), tooltip: "Update data"),
],
rows: controller.userList // accessing list from Getx controller
.map(
(user) => DataRow(
cells: [
DataCell(
Text(user.name),
),
DataCell(
Text(user.email),
),
DataCell(
IconButton(
onPressed: () {
controller.currentIndex =
controller.userList.indexOf(user);
controller.updateTextControllers(user);
},
icon: Icon(
Icons.edit,
color: Colors.black,
),
),
),
],
),
)
.toList(),
);
return Scaffold(
appBar: AppBar(
title: Text("Data add to List Table using Form"),
),
body: Container(
child: Column(
children: <Widget>[
// GetBuilder rebuilds when update() is called
GetBuilder<FormController>(
builder: (controller) => bodyData(),
),
Padding(
padding: EdgeInsets.all(10.0),
child: Form(
key: form,
child: Container(
child: Column(
children: <Widget>[
TextFormField(
controller: controller.nameController,
focusNode: _focusNode,
keyboardType: TextInputType.text,
autocorrect: false,
maxLines: 1,
validator: (value) {
if (value.isEmpty) {
return 'This field is required';
}
return null;
},
decoration: InputDecoration(
labelText: 'Name',
hintText: 'Name',
labelStyle: new TextStyle(
decorationStyle: TextDecorationStyle.solid),
),
),
SizedBox(
height: 10,
),
TextFormField(
controller: controller.emailController,
keyboardType: TextInputType.text,
autocorrect: false,
maxLines: 1,
validator: (value) {
if (value.isEmpty) {
return 'This field is required';
}
return null;
},
decoration: InputDecoration(
labelText: 'Email',
hintText: 'Email',
labelStyle: new TextStyle(
decorationStyle: TextDecorationStyle.solid)),
),
SizedBox(
height: 10,
),
Column(
children: <Widget>[
Center(
child: Row(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Row(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
TextButton(
child: Text("Add"),
onPressed: () {
form.currentState.save();
controller.addUserToList(
controller.nameController.text,
controller.emailController.text,
);
},
),
TextButton(
child: Text("Update"),
onPressed: () {
form.currentState.save();
controller.updateForm();
},
),
],
),
Row(
crossAxisAlignment: CrossAxisAlignment.end,
mainAxisAlignment: MainAxisAlignment.end,
children: <Widget>[
ElevatedButton(
child: Text("Save and Exit"),
onPressed: () {
form.currentState.save();
controller.updateLanguageInformation(); // all this function does is print the list
Navigator.pop(
context); // don't need to pass anything here
},
),
],
),
],
),
),
],
),
],
),
),
),
),
],
),
),
);
}
}
And here's your other page. I just threw in a ListView.builder wrapped in a GetBuilder<FormController> for demo purposes. It can now be stateless.
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("Testing List View Data From second page to first page"),
),
body: Column(
children: <Widget>[
Expanded(
child: GetBuilder<FormController>(
builder: (controller) => ListView.builder(
itemCount: controller.userList.length,
itemBuilder: (context, index) => Row(
mainAxisAlignment: MainAxisAlignment.spaceAround,
children: [
Text(controller.userList[index].name),
Text(controller.userList[index].email),
],
),
),
),
),
SizedBox(
height: 10.0,
),
ElevatedButton(
onPressed: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => Episode5(),
),
);
},
child: Text("Go to Form"),
),
],
),
);
}
}
As your app expands you can create more controller classes and they're all very easily accessible from anywhere. Its a way easier and cleaner way to do things than manually passing data around everywhere.

How do I execute Navigator.of(context).pop() when the state doesn't return an error in BLoC?

I'm building a very simple 2FA application, which scans a QR code and then it shows the TOTP code on the screen. However, I don't know how to go back to previous screen using Navigator.of(context).pop(). When I do that in my app, it crashes.
Here's a short video how my app reacts to this: https://streamable.com/ao6qql
How do I check if the form is empty? If it is, I want to show the Alert Dialog, but it returns to the previous screen and it is showing the AlertDialog. How do I do it so my Navigator.of(context).pop() executes when the form is filled?
Code:
The block which crashes my app:
BlocListener<ManualInputBloc, ManualInputState>(
listener: (context, state) {
if (state is ManualInputError) {
Platform.isAndroid
? CustomAlertDialog.showAndroidAlertDialog(
context,
state.alertDialogErrorTitle,
state.alertDialogErrorContent,
)
: CustomAlertDialog.showIosAlertDialog(
context,
state.alertDialogErrorTitle,
state.alertDialogErrorContent,
);
}
},
child: TextButton(
onPressed: () {
final manualInputBloc =
BlocProvider.of<ManualInputBloc>(context);
manualInputBloc.add(
GetFormTextEvent(
secretKey,
issuer,
accountName,
numberOfDigits,
timeStep,
),
);
Navigator.of(context).pop();
},
child: Text('add').tr(),
),
)
The whole screen:
import 'dart:io';
import 'package:duckie/blocs/manual_input/manual_input_bloc.dart';
import 'package:duckie/screens/widgets/alert_dialog.dart';
import 'package:duckie/screens/widgets/custom_text_field.dart';
import 'package:duckie/shared/text_styles.dart';
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:easy_localization/easy_localization.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
class ManualInputScreen extends StatefulWidget {
#override
_ManualInputScreenState createState() => _ManualInputScreenState();
}
class _ManualInputScreenState extends State<ManualInputScreen> {
String secretKey;
String issuer;
String accountName;
String numberOfDigits = '6';
String timeStep = '30';
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(
'manual-input',
style: TextStyles.appBarText,
).tr(),
centerTitle: true,
elevation: 0.0,
actions: [
BlocListener<ManualInputBloc, ManualInputState>(
listener: (context, state) {
if (state is ManualInputError) {
Platform.isAndroid
? CustomAlertDialog.showAndroidAlertDialog(
context,
state.alertDialogErrorTitle,
state.alertDialogErrorContent,
)
: CustomAlertDialog.showIosAlertDialog(
context,
state.alertDialogErrorTitle,
state.alertDialogErrorContent,
);
}
},
child: TextButton(
onPressed: () {
final manualInputBloc =
BlocProvider.of<ManualInputBloc>(context);
manualInputBloc.add(
GetFormTextEvent(
secretKey,
issuer,
accountName,
numberOfDigits,
timeStep,
),
);
Navigator.of(context).pop();
},
child: Text('add').tr(),
),
)
],
),
body: Container(
padding: EdgeInsets.all(8.0),
child: ListView(
children: [
CustomTextField(
labelText: 'secret-key'.tr(),
onChanged: (value) {
setState(() {
secretKey = value;
});
},
),
SizedBox(
height: 8.0,
),
CustomTextField(
labelText: 'issuer'.tr(),
onChanged: (value) {
issuer = value;
},
),
SizedBox(
height: 8.0,
),
CustomTextField(
labelText: 'account-name'.tr(),
onChanged: (value) {
setState(() {
accountName = value;
});
},
),
SizedBox(
height: 8.0,
),
Platform.isAndroid
? ListBody(
children: [
Text('number-of-digits').tr(),
SizedBox(
height: 5.0,
),
DropdownButton(
value: numberOfDigits,
onChanged: (value) {
setState(() {
numberOfDigits = value;
});
},
items: [
DropdownMenuItem(
value: '6',
child: Text('6'),
),
DropdownMenuItem(
value: '8',
child: Text('8'),
),
],
)
],
)
: ListBody(
children: [
Text('number-of-digits').tr(),
SizedBox(
height: 5.0,
),
CupertinoSegmentedControl(
groupValue: numberOfDigits,
children: {
'6': Text('6'),
'8': Text('8'),
},
onValueChanged: (value) {
setState(() {
numberOfDigits = value;
});
},
),
],
),
SizedBox(
height: 8.0,
),
Platform.isAndroid
? ListBody(
children: [
Text('time-step').tr(),
SizedBox(
height: 5.0,
),
DropdownButton(
value: timeStep,
onChanged: (value) {
setState(() {
timeStep = value;
});
},
items: [
DropdownMenuItem(
value: '30',
child: Text('30'),
),
DropdownMenuItem(
value: '60',
child: Text('60'),
),
],
)
],
)
: ListBody(
children: [
Text('time-step').tr(),
SizedBox(
height: 5.0,
),
CupertinoSegmentedControl(
groupValue: timeStep,
children: {
'30': Text('30'),
'60': Text('60'),
},
onValueChanged: (value) {
setState(() {
timeStep = value;
});
},
),
],
),
],
),
),
);
}
}

How to change event in BLoC in Flutter?

I have an app which creates a 2FA totp key. When I click "Add" button when a form is not filled, it shows an Alert Dialog. If I click it second time (still, the form isn't filled), the alert dialog doesn't show up. How do I show the Alert Dialog for the infinite times? I used BlocConsumer to listen to changes and show the Alert Dialog when the state is ManualInputError, and a BlocBuilder to show the actual TextButton.
Code:
import 'dart:io';
import 'package:duckie/blocs/manual_input/manual_input_bloc.dart';
import 'package:duckie/screens/widgets/alert_dialog.dart';
import 'package:duckie/screens/widgets/custom_text_field.dart';
import 'package:duckie/shared/text_styles.dart';
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:easy_localization/easy_localization.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
class ManualInputScreen extends StatefulWidget {
#override
_ManualInputScreenState createState() => _ManualInputScreenState();
}
class _ManualInputScreenState extends State<ManualInputScreen> {
String secretKey;
String issuer;
String accountName;
String numberOfDigits = '6';
String timeStep = '30';
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(
'manual-input',
style: TextStyles.appBarText,
).tr(),
centerTitle: true,
elevation: 0.0,
actions: [
BlocConsumer<ManualInputBloc, ManualInputState>(
listener: (context, state) {
if (state is ManualInputError) {
Platform.isAndroid
? CustomAlertDialog.showAndroidAlertDialog(
context,
state.alertDialogErrorTitle,
state.alertDialogErrorContent)
: CustomAlertDialog.showIosAlertDialog(
context,
state.alertDialogErrorTitle,
state.alertDialogErrorContent);
BlocProvider.of<ManualInputBloc>(context).close();
}
},
builder: (context, state) {
if (state is ManualInputInitial || state is ManualInputFinal) {
return TextButton(
onPressed: () {
BlocProvider.of<ManualInputBloc>(context).add(
GetFormTextEvent(secretKey, issuer, accountName,
numberOfDigits, timeStep));
},
child: Text('add').tr(),
);
}
return TextButton(
onPressed: () {},
child: Text('add').tr(),
);
},
)
],
),
body: Container(
padding: EdgeInsets.all(8.0),
child: ListView(
children: [
CustomTextField(
labelText: 'secret-key'.tr(),
onChanged: (value) {
setState(() {
secretKey = value;
});
},
),
SizedBox(
height: 8.0,
),
CustomTextField(
labelText: 'issuer'.tr(),
onChanged: (value) {
issuer = value;
},
),
SizedBox(
height: 8.0,
),
CustomTextField(
labelText: 'account-name'.tr(),
onChanged: (value) {
setState(() {
accountName = value;
});
},
),
SizedBox(
height: 8.0,
),
Platform.isAndroid
? ListBody(
children: [
Text('number-of-digits').tr(),
SizedBox(
height: 5.0,
),
DropdownButton(
value: numberOfDigits,
onChanged: (value) {
setState(() {
numberOfDigits = value;
});
},
items: [
DropdownMenuItem(
value: '6',
child: Text('6'),
),
DropdownMenuItem(
value: '8',
child: Text('8'),
),
],
)
],
)
: ListBody(
children: [
Text('number-of-digits').tr(),
SizedBox(
height: 5.0,
),
CupertinoSegmentedControl(
groupValue: numberOfDigits,
children: {
'6': Text('6'),
'8': Text('8'),
},
onValueChanged: (value) {
setState(() {
numberOfDigits = value;
});
},
),
],
),
SizedBox(
height: 8.0,
),
Platform.isAndroid
? ListBody(
children: [
Text('time-step').tr(),
SizedBox(
height: 5.0,
),
DropdownButton(
value: timeStep,
onChanged: (value) {
setState(() {
timeStep = value;
});
},
items: [
DropdownMenuItem(
value: '30',
child: Text('30'),
),
DropdownMenuItem(
value: '60',
child: Text('60'),
),
],
)
],
)
: ListBody(
children: [
Text('time-step').tr(),
SizedBox(
height: 5.0,
),
CupertinoSegmentedControl(
groupValue: timeStep,
children: {
'30': Text('30'),
'60': Text('60'),
},
onValueChanged: (value) {
setState(() {
timeStep = value;
});
},
),
],
),
],
),
),
);
}
}
The reason is that you close(kill) the BLoC here
BlocProvider.of<ManualInputBloc>(context).close();
Change the listener to that
listener: (context, state) {
if (state is ManualInputError) {
Platform.isAndroid
? CustomAlertDialog.showAndroidAlertDialog(
context,
state.alertDialogErrorTitle,
state.alertDialogErrorContent)
: CustomAlertDialog.showIosAlertDialog(
context,
state.alertDialogErrorTitle,
state.alertDialogErrorContent);
}
},