type '_Type' is not a subtype of type 'String' - flutter

Question

So i am a beginner in flutter and am trying to learn via tutorials, so here I am trying to make todo app using sqflite and everything is perfect and no error is shown in the editor but on clicking floating action button in notelist file it shows this error-
The following _TypeError was thrown building Builder:
type '_Type' is not a subtype of type 'String'
heres my main.dart file
void main() {
runApp(MaterialApp(
home: NoteList(),
));
}
here notelist
class NoteList extends StatefulWidget {
const NoteList({Key? key}) : super(key: key);
#override
_NoteListState createState() => _NoteListState();
}
class _NoteListState extends State<NoteList> {
int count = 0;
DatabaseHelper databaseHelper = DatabaseHelper();
late List<Note> noteList;
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Note List'),
),
body: getNoteListView(),
floatingActionButton: FloatingActionButton(
onPressed: () {
debugPrint('fab clicked');
navigateToDetail(Note('', '', 2 ,''),'Add Note');
},
child: Icon(Icons.add),
),
);
}
ListView getNoteListView(){
return ListView.builder(
itemCount: count,
itemBuilder: (context, index){
return Card(
color: Colors.white,
elevation: 2.0,
child: ListTile(
leading: CircleAvatar(
backgroundColor: getPriorityColor(this.noteList[index].priority),
child: getPriorityIcon(this.noteList[index].priority),
),
title: Text(this.noteList[index].title!,),
subtitle: Text(this.noteList[index].date!),
trailing: IconButton(onPressed: (){
_delete(context, noteList[index]);
},
icon: Icon(Icons.delete),
),
onTap: (){
debugPrint('tapped');
navigateToDetail(noteList[index],'Edit Note');
},
),
);
}
);
}
void navigateToDetail(Note note, String title) async{
bool result = await Navigator.push(context, MaterialPageRoute(builder: (context) {
return NoteDetail(appBarTitle: Title, note: note);
}));
if (result == true) {
updateListView();
}
}
// Returns the priority color
Color getPriorityColor(int? priority) {
switch (priority) {
case 1:
return Colors.red;
break;
case 2:
return Colors.yellow;
break;
default:
return Colors.yellow;
}
}
// Returns the priority icon
Icon getPriorityIcon(int? priority) {
switch (priority) {
case 1:
return Icon(Icons.play_arrow);
break;
case 2:
return Icon(Icons.keyboard_arrow_right);
break;
default:
return Icon(Icons.keyboard_arrow_right);
}
}
void _delete(BuildContext context, Note note) async {
int? result = await databaseHelper.deleteNote(note.id);
if (result != 0) {
_showSnackBar(context, 'Note Deleted Successfully');
updateListView();
}
}
void _showSnackBar(BuildContext context, String message) {
final snackBar = SnackBar(content: Text(message));
Scaffold.of(context).showSnackBar(snackBar);
}
void updateListView() {
final Future<Database> dbFuture = databaseHelper.initializeDatabase();
dbFuture.then((database) {
Future<List<Note>> noteListFuture = databaseHelper.getNoteList();
noteListFuture.then((noteList) {
setState(() {
this.noteList = noteList;
this.count = noteList.length;
});
});
});
}
}
and heres notedetail file
class NoteDetail extends StatefulWidget {
final Note note;
final appBarTitle;
NoteDetail( {Key? key,required this.appBarTitle, required this.note}) : super(key: key);
#override
_NoteDetailState createState() => _NoteDetailState(this.note, this.appBarTitle);
}
class _NoteDetailState extends State<NoteDetail> {
static var _priorities = ['High', 'Low'];
DatabaseHelper helper = DatabaseHelper();
TextEditingController titleController = TextEditingController();
TextEditingController descController = TextEditingController();
String appBarTitle;
Note note;
_NoteDetailState(this.note , this.appBarTitle);
#override
Widget build(BuildContext context) {
titleController.text = note.title!;
descController.text = note.description!;
return Scaffold(
appBar: AppBar(
title: Text(appBarTitle),
),
body: Container(
padding: EdgeInsets.all(10),
child: ListView(
children: [
ListTile(
title: DropdownButton(
items: _priorities.map((dropDownStringItem) {
return DropdownMenuItem (
value: dropDownStringItem,
child: Text(dropDownStringItem),
);
}).toList(),
value: getPriorityAsString(note.priority),
onChanged: (valueSelectedByUser) {
setState(() {
debugPrint('User selected $valueSelectedByUser');
updatePriorityAsInt(valueSelectedByUser);
});
}
),
),
SizedBox(height: 10,),
Container(
child: TextField(
controller: titleController,
onChanged: (value) {
debugPrint('something changed in the title textfield ');
updateTitle();
},
decoration: InputDecoration(
labelText: 'Title',
border: OutlineInputBorder(
borderRadius: BorderRadius.circular(5.0),
)
),
),
),
SizedBox(height: 10,),
Container(
child: TextField(
controller: descController,
onChanged: (value) {
debugPrint('something changed in the description textfield ');
updateDescription();
},
decoration: InputDecoration(
labelText: 'Description',
border: OutlineInputBorder(
borderRadius: BorderRadius.circular(5.0),
)
),
),
),
Container(
padding: EdgeInsets.all(10),
child: Row(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Container(
width: 120,
height: 50,
padding: EdgeInsets.all(5),
child: ElevatedButton(onPressed: (){
debugPrint('add button clicked');
_save();
}, child: Text('Save',
style: TextStyle(
fontSize: 18
),
)
),
),
Container(
width: 120,
height: 50,
padding: EdgeInsets.all(5),
child: ElevatedButton(onPressed: (){
_delete();
debugPrint('Delete button clicked');
}, child: Text('Delete',
style: TextStyle(
fontSize: 18
),)),
),
],
),
)
],
),
),
);
}
// Convert int priority to String priority and display it to user in DropDown
String getPriorityAsString(int? value) {
String priority = '';
switch (value) {
case 1:
priority = _priorities[0]; // 'High'
break;
case 2:
priority = _priorities[1]; // 'Low'
break;
}
return priority;
}
// Convert the String priority in the form of integer before saving it to Database
void updatePriorityAsInt(var value) {
switch (value) {
case 'High':
note.priority = 1;
break;
case 'Low':
note.priority = 2;
break;
}
}
// Update the title of Note object
void updateTitle(){
note.title = titleController.text;
}
// Update the description of Note object
void updateDescription() {
note.description = descController.text;
}
void _delete() async {
moveToLastScreen();
// Case 1: If user is trying to delete the NEW NOTE i.e. he has come to
// the detail page by pressing the FAB of NoteList page.
if (note.id == null) {
_showAlertDialog('Status', 'No Note was deleted');
return;
}
// Case 2: User is trying to delete the old note that already has a valid ID.
int? result = await helper.deleteNote(note.id);
if (result != 0) {
_showAlertDialog('Status', 'Note Deleted Successfully');
} else {
_showAlertDialog('Status', 'Error Occured while Deleting Note');
}
}
void moveToLastScreen() {
Navigator.pop(context, true);
}
void _showAlertDialog(String title, String message) {
AlertDialog alertDialog = AlertDialog(
title: Text(title),
content: Text(message),
);
showDialog(
context: context,
builder: (_) => alertDialog
);
}
// Save data to database
void _save() async {
moveToLastScreen();
note.date = DateFormat.yMMMd().format(DateTime.now());
int? result;
if (note.id != null) { // Case 1: Update operation
result = await helper.updateNote(note);
} else { // Case 2: Insert Operation
result = await helper.insertNote(note);
}
if (result != 0) { // Success
_showAlertDialog('Status', 'Note Saved Successfully');
} else { // Failure
_showAlertDialog('Status', 'Problem Saving Note');
}
}
}

Answer 1

This looks like a spelling mistake.
void navigateToDetail(Note note, String title) async{
...
// change Title into title
return NoteDetail(appBarTitle: title, note: note);
...