getting two major errors - flutter

Question

While creating to-do app I got stuck in the middle of the execution of project
import 'package:flutter/material.dart';
import '../database_helper.dart';
import '../note.dart';
import 'package:intl/intl.dart';
class NoteDetail extends StatefulWidget {
final String appBarTitle;
final Note note;
NoteDetail(this.note, this.appBarTitle);
#override
State<StatefulWidget> createstate(){
return NoteDetailState(this.note,this.appBarTitle);
}
State<StatefulWidget> createState() {
throw UnimplementedError();
}
}
class NoteDetailState extends State<NoteDetail>{
static var _Priorities=['HIGH','LOW'];
DatabaseHelper helper=DatabaseHelper();
String appBarTitle;
Note note;
NoteDetailState(this.note,this.appBarTitle);
TextEditingController titleController =TextEditingController();
TextEditingController descriptionController=TextEditingController();
#override
Widget build(BuildContext context) {
TextStyle textStyle=Theme.of(context).textTheme.****title****;-this is the error i am getting
titleController.text=note.title;
descriptionController=note.description as TextEditingController;
return WillPopScope(
onWillPop: ()**{** - here is the another error
moveToLastScreen();},
child: Scaffold(
appBar: AppBar(
title: Text(appBarTitle),
leading: IconButton(
icon:Icon(Icons.arrow_back),
onPressed: (){
moveToLastScreen();
},
),
),
body: Padding(
padding: EdgeInsets.all(10.0),
child: Card(
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(15.0),
),
child: ListView(
children: <Widget>[
Padding(
padding: EdgeInsets.only(top: 15.0, bottom: 5.0),
//dropdown menu
child: new ListTile(
leading: const Icon(Icons.low_priority),
title: DropdownButton(
items: _Priorities.map((String dropDownStringItem) {
return DropdownMenuItem<String>(
value: dropDownStringItem,
child: Text(dropDownStringItem,
style: TextStyle(
fontSize: 20.0,
fontWeight: FontWeight.bold,
color: Colors.red)),
);
}).toList(),
value: getPriorityAsString(note.priority),
onChanged: (valueSelectedByUser) {
setState(() {
updatePriorityAsInt(valueSelectedByUser);
});
}),
),
),
// Second Element
Padding(
padding:
EdgeInsets.only(top: 15.0, bottom: 15.0, left: 15.0),
child: TextField(
controller: titleController,
style: textStyle,
onChanged: (value) {
updateTile();
},
decoration: InputDecoration(
labelText: 'Title',
labelStyle: textStyle,
icon: Icon(Icons.title),
),
),
),
// Third Element
Padding(
padding:
EdgeInsets.only(top: 15.0, bottom: 15.0, left: 15.0),
child: TextField(
controller: descriptionController,
style: textStyle,
onChanged: (value) {
updatedescription();
},
decoration: InputDecoration(
labelText: 'Details',
icon: Icon(Icons.details),
),
),
),
// Fourth Element
Padding(
padding: EdgeInsets.all(15.0),
child: Row(
children: <Widget>[
Expanded(
child: RaisedButton(
textColor: Colors.white,
color: Colors.green,
padding: const EdgeInsets.all(8.0),
child: Text(
'Save',
textScaleFactor: 1.5,
),
onPressed: () {
setState(() {
debugPrint("Save button clicked");
_save();
});
},
),
),
Container(
width: 5.0,
),
Expanded(
child: RaisedButton(
textColor: Colors.white,
color: Colors.red,
padding: const EdgeInsets.all(8.0),
child: Text(
'Delete',
textScaleFactor: 1.5,
),
onPressed: () {
setState(() {
_delete();
});
},
),
),
],
),
),
],
),
),
),
),
);
}
void updateTile(){
note.title=titleController.text;
}
void updatedescription(){
note.description=descriptionController.text;
}
void moveToLastScreen(){
Navigator.pop(context,true);
}
void _save() async{
moveToLastScreen();
note.date=DateFormat.yMMMd().format(DateTime.now());
int result;
if (note.id !=null) {
result=await helper.updateNote(note);
}else{
result=await helper.insertNote(note);
}
if (note !=0) {
__showAlertDialog('Status','Note Saved Sucessfully');
}else{
__showAlertDialog('status', 'problem solving note');
}
}
void __showAlertDialog(String title, String message) {
AlertDialog alertDialog=AlertDialog(
title: Text(title),
content: Text(message),
);
showDialog(context: context, builder: (_)=>alertDialog);
}
void updatePriorityAsInt(Object? valueSelectedByUser) {
var value;
switch (value) {
case 'HIGH':
note.Priority=1;
break;
case 'LOW':
note.Priority=2;
break;
}
}
Future<void> _delete() async {
moveToLastScreen();
if (note.id!=null) {
__showAlertDialog('status', 'first add note');
return;
}
int result= await helper.deleteNote(note.id);
if (result !=0) {
__showAlertDialog('Status','Note deleted Sucessfully');
}else{
__showAlertDialog('status', '404 error');
}
}
getPriorityAsString(int value) {
String ?priority;
switch (value) {
case 1:
priority=_Priorities[0];
break;
case 2:
priority=_Priorities[1];
break;
}
return priority;
}
}
I am getting error like this.
The getter 'title' isn't defined for the type 'TextTheme'.
Try importing the library that defines 'title', correcting the name to the name of an existing getter, or defining a getter or field named 'title'.
The body might complete normally, causing 'null' to be returned, but the return type is a potentially non-nullable type.
Try adding either a return or a throw statement at the end.
Please anyone can help me

Answer 1

Flutter changed the names for theme a while ago, fix the first error using this for example, or use titleMedium/titleBig.
TextStyle textStyle=Theme.of(context).textTheme.titleSmall
Fix the 2. error by adding a default value to your last function. Null-Safety forces you to return something non-null from your function, so either make the function nullable, or change the bahaviour to this:
getPriorityAsString(int value) {
String priority = "";
switch (value) {
case 1:
priority = "";
break;
case 2:
priority = "";
break;
}
return priority;
}