TextFromField is losing value after sate changed - flutter

Question

TextFromField is losing its value when the state change.
Here is the full code https://github.com/imSaharukh/cgpa_final.git
How can I fix that?
Check this GIF

Answer 1

The problem is how you create your TextEditingControllers. Everytime the build method is called new TextEditingControllers are created.
What you want to do is create 3 TextEditingController variables at the top inside _MyHomePageState class. (Also no need to use the new keyword in dart).
class _MyHomePageState extends State<MyHomePage> {
final _formKey = GlobalKey<FormState>();
TextEditingController nameController = TextEditingController();
TextEditingController cgpaController = TextEditingController();
TextEditingController crController = TextEditingController();
and pass these to your CustomCard
child: CustomCard(
key: UniqueKey(),
index: index,
cgpa: cgpa,
namecontroller: nameController,
cgpacontroller: cgpaController,
crcontroller: crController),
Hope this helps
EDIT:
I don't know how to create a pull request but I made some changes for you and tested it on an iOS sim.
What i did:
Renamed Details to Course
Converted CusomCard into an statefull widget
Only a Course object is now passed to CustomCard
The dismissable now gets a key based on the course.
Moved the controllers to CustomCard
Modified some code in CGPA to make it all work
class _MyHomePageState extends State<MyHomePage> {
final _formKey = GlobalKey<FormState>();
#override
Widget build(BuildContext context) {
return Scaffold(
body: SafeArea(
child: Stack(
children: [
Column(
children: [
Expanded(
child: Consumer<CGPA>(builder: (context, cgpa, _) {
return Form(
key: _formKey,
child: ListView.builder(
scrollDirection: Axis.vertical,
shrinkWrap: true,
itemCount: cgpa.courses.length,
itemBuilder: (BuildContext context, int index) {
return Dismissible(
key: Key(cgpa.getKeyValue(index)),
onDismissed: (direction) {
cgpa.remove(index);
print(cgpa.courses.length);
},
child: CustomCard(
course: cgpa.getCourse(index),
),
);
},
),
);
}),
),
],
),
Align(
alignment: Alignment.bottomRight,
child: Padding(
padding: const EdgeInsets.all(15.0),
child: FloatingActionButton(
child: Icon(Icons.add),
onPressed: () {
Provider.of<CGPA>(context, listen: false).add();
// print(cgpa.details.length);
// cgpa.details[indexs] = Details();
},
),
),
),
],
),
),
floatingActionButton: OutlineButton(
onPressed: () {
// for (var item in cgpa.details) {
// print(item.credit);
// }
},
child: Padding(
padding: const EdgeInsets.symmetric(horizontal: 30),
child: Text("calculate"),
),
shape: new RoundedRectangleBorder(
borderRadius: new BorderRadius.circular(30.0),
),
),
floatingActionButtonLocation: FloatingActionButtonLocation.centerFloat,
);
}
}
CustomCard
class CustomCard extends StatefulWidget {
CustomCard({#required this.course});
final Course course;
#override
_CustomCardState createState() => _CustomCardState();
}
class _CustomCardState extends State<CustomCard> {
TextEditingController nameController;
TextEditingController cgpaController;
TextEditingController crController;
#override
void initState() {
super.initState();
nameController = TextEditingController(text: widget.course.name);
cgpaController = TextEditingController(
text: widget.course.gpa == null ? "" : widget.course.gpa.toString());
crController = TextEditingController(
text: widget.course.credit == null
? ""
: widget.course.credit.toString());
}
#override
Widget build(BuildContext context) {
return Card(
child: Padding(
padding: const EdgeInsets.all(8.0),
child: Row(
children: [
Expanded(
flex: 3,
child: TextFormField(
controller: nameController,
decoration: InputDecoration(labelText: "COURSE NAME"),
onChanged: (value) {
widget.course.name = value;
},
),
),
SizedBox(
width: 10,
),
Expanded(
child: TextFormField(
controller: cgpaController,
keyboardType: TextInputType.number,
decoration: InputDecoration(labelText: "GPA"),
onChanged: (value) {
//print(value);
widget.course.gpa = double.parse(value);
},
validator: (value) {
if (double.parse(value) > 4 && double.parse(value) < 0) {
return 'can\'t more then 4';
}
return null;
},
),
),
SizedBox(
width: 10,
),
Expanded(
child: TextFormField(
controller: crController,
keyboardType: TextInputType.number,
decoration: InputDecoration(labelText: "CREDIT"),
onChanged: (value) {
widget.course.credit = double.parse(value);
},
validator: (value) {
if (value.isEmpty) {
return 'can\'t be empty';
}
return null;
},
),
),
],
),
),
);
}
}
CGPA
class CGPA with ChangeNotifier {
Map<int, Course> courses = new Map();
var index = 0;
add() {
courses[index] = Course();
index++;
notifyListeners();
}
remove(int listIndex) {
courses.remove(courses.keys.toList()[listIndex]);
notifyListeners();
}
String getKeyValue(int listIndex) => courses.keys.toList()[listIndex].toString();
Course getCourse(int listIndex) => courses.values.toList()[listIndex];
}
class Course {
Course({this.credit, this.gpa, this.name});
String name;
double credit;
double gpa;
#override
String toString() {
return 'Course{name: $name, credit: $credit, gpa: $gpa}';
}
}