The method 'changeeventdescription' was called on null - flutter

Question

I have looked at many answers to other questions but I think I am missing something still. I am developing a flutter app and the page that I am having trouble with is a page where I create meetings for a calendar.
When I look at the debug log I see that the eventProvider is null. I copied the structure from another screen in my app and everything works fine there. What have I missed?
Here is the code from the screen:
final eventRef = FirebaseFirestore.instance.collection(('events'));
class AddEventScreen extends StatefulWidget {
static const String id = 'add_event_screen';
final Event event;
AddEventScreen([this.event]);
#override
_AddEventScreenState createState() => _AddEventScreenState();
}
class _AddEventScreenState extends State<AddEventScreen> {
final _db = FirebaseFirestore.instance;
final eventNameController = TextEditingController();
final eventStartTimeController = TextEditingController();
final eventDurationController = TextEditingController();
final eventDateController = TextEditingController();
final eventDescriptionController = TextEditingController();
#override
void dispose() {
eventNameController.dispose();
eventStartTimeController.dispose();
eventDurationController.dispose();
eventDateController.dispose();
eventDescriptionController.dispose();
super.dispose();
}
bool showSpinner = false;
String eventName;
String eventStartTime;
String eventDuration;
String eventData;
String eventDescription;
getCurentAgencyEvents() async {
if (globals.agencyId == null) {
eventNameController.text = "";
eventStartTimeController.text = "";
eventDurationController.text = "";
eventDateController.text = "";
eventDescriptionController.text = "";
} else {
final DocumentSnapshot currentEvent =
await eventRef.doc(globals.agencyId).get();
// existing record
// Updates Controllers
eventNameController.text = currentEvent.data()["name"];
eventStartTimeController.text = currentEvent.data()['address1'];
eventDurationController.text = currentEvent.data()['address2'];
eventDateController.text = currentEvent.data()['city'];
eventDescriptionController.text = currentEvent.data()['state'];
// Updates State
new Future.delayed(Duration.zero, () {
final eventProvider =
Provider.of<EventProvider>(context, listen: false);
eventProvider.loadValues(widget.event);
});
}
}
#override
void initState() {
super.initState();
}
#override
Widget build(BuildContext context) {
final eventProvider = Provider.of<EventProvider>(context);
final _firestoreService = FirestoreService();
DateTime _date = new DateTime.now();
TimeOfDay _time = new TimeOfDay.now();
Duration initialtimer = new Duration();
DateTime _selectedDate = DateTime.now();
TimeOfDay _timePicked = TimeOfDay.now();
return Scaffold(
appBar: AppBar(
title: Row(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Image.asset('assets/images/Appbar_logo.png',
fit: BoxFit.cover, height: 56),
],
),
),
backgroundColor: Colors.white,
body: SafeArea(
child: SingleChildScrollView(
child: Padding(
padding: const EdgeInsets.all(20.0),
child: Column(
children: <Widget>[
Text(
'Event Editor',
style: TextStyle(
fontSize: 30,
fontWeight: FontWeight.w800,
),
),
SizedBox(
height: 30.0,
),
TextField(
controller: eventNameController,
keyboardType: TextInputType.text,
textAlign: TextAlign.center,
onChanged: (value) {
eventProvider.changeeventname(value);
},
decoration: kTextFieldDecoration.copyWith(
hintText: 'Event Name', labelText: 'Event Name'),
),
SizedBox(
height: 8.0,
),
TextField(
controller: eventDurationController,
textAlign: TextAlign.center,
onChanged: (value) {
eventProvider.changeeventduration(value);
},
decoration: kTextFieldDecoration.copyWith(
hintText: 'Duration', labelText: 'Duration'),
),
SizedBox(
height: 8.0,
),
TextField(
controller: eventDateController,
keyboardType: TextInputType.datetime,
textAlign: TextAlign.center,
onTap: () async {
DateTime _datePicked = await showDatePicker(
context: context,
initialDate: _selectedDate,
//firstDate: new DateTime.now().add(Duration(days: -365)),
firstDate: new DateTime(2020),
lastDate: new DateTime(2022));
if (_date != null && _date != _datePicked) {
setState(() {
eventDateController.text =
DateFormat("MM/dd/yyyy").format(_datePicked);
eventProvider.changeeventdate(_datePicked);
_selectedDate = _datePicked;
//DateFormat("MM/dd/yyyy").format(_date));
});
}
},
onChanged: (value) {
eventProvider.changeeventdate(_date);
},
decoration: kTextFieldDecoration.copyWith(
hintText: 'Date',
labelText: 'Date',
),
),
SizedBox(
height: 8.0,
),
TextField(
controller: eventStartTimeController,
keyboardType: TextInputType.text,
textAlign: TextAlign.center,
onTap: () async {
TimeOfDay _timePicked = await showTimePicker(
context: context,
initialTime: new TimeOfDay.now());
//if (_timePicked != null) {
setState(() {
eventStartTimeController.text = _timePicked.format(context);
});
//}
},
onChanged: (value) {
eventProvider.changeeventstarttime(_timePicked);
},
decoration: kTextFieldDecoration.copyWith(
hintText: 'Start Time',
labelText: 'Start Time',
),
),
SizedBox(
height: 8.0,
),
TextField(
controller: eventDescriptionController,
keyboardType: TextInputType.text,
textAlign: TextAlign.center,
onChanged: (value) {
eventProvider.changeeventdescription(value);
},
decoration: kTextFieldDecoration.copyWith(
hintText: 'Description', labelText: 'Description'),
),
SizedBox(
height: 8.0,
),
RoundedButton(
title: 'Save Event',
colour: Colors.blueAccent,
onPressed: () async {
setState(() {
showSpinner = true;
});
try {
globals.newEvent = true;
eventProvider.saveEvent();
Navigator.of(context).pushReplacement(MaterialPageRoute(
builder: (context) => AppointmentCalendarScreen()));
setState(() {
showSpinner = false;
});
} catch (e) {
// todo: add better error handling
print(e);
}
},
),
SizedBox(
height: 8.0,
),
(widget != null)
? RoundedButton(
title: 'Delete',
colour: Colors.red,
onPressed: () async {
setState(() {
showSpinner = true;
});
try {
//agencyProvider.deleteAgency(globals.currentUid);
Navigator.of(context).pushReplacement(MaterialPageRoute(
builder: (context) => AppointmentCalendarScreen()));
setState(() {
showSpinner = false;
});
} catch (e) {
// todo: add better error handling
print(e);
}
},
)
: Container()
],
),
),
),
),
);
}
}
Here is the debug log and I get the same message for each input control:
======== Exception caught by widgets ===============================================================
The following NoSuchMethodError was thrown while calling onChanged:
The method 'changeeventname' was called on null.
Receiver: null
Tried calling: changeeventname("Test event")
Here is the code for the EventProvider:
class EventProvider with ChangeNotifier {
final firestoreService = FirestoreService();
FirebaseFirestore _db = FirebaseFirestore.instance;
final eventRef = FirebaseFirestore.instance.collection(('events'));
String _eventName;
TimeOfDay _eventStartTime;
String _eventDuration;
DateTime _eventDate;
String _eventDescription;
//Getters
String get eventName => _eventName;
TimeOfDay get eventStartTime => _eventStartTime;
String get eventDuration => _eventDuration;
DateTime get eventDate => _eventDate;
String get eventDescription => _eventDescription;
final EventProvider eventProvider = new EventProvider();
//Setters
changeeventname(String value) {
_eventName = value;
notifyListeners();
}
changeeventstarttime(TimeOfDay value) {
_eventStartTime = value;
notifyListeners();
}
changeeventduration(String value) {
_eventDuration = value;
notifyListeners();
}
changeeventdate(DateTime value) {
_eventDate = value;
notifyListeners();
}
changeeventdescription(String value) {
_eventDescription = value;
notifyListeners();
}
loadValues(Event event) {
_eventName = event.eventName;
_eventStartTime = event.eventStartTime;
_eventDuration = event.eventDuration;
_eventDate = event.eventDate;
_eventDescription = event.eventDescription;
}
saveEvent() {
var newEvent = Event(
eventName: _eventName,
eventStartTime: _eventStartTime,
eventDuration: _eventDuration,
eventDate: _eventDate,
eventDescription: _eventDescription);
// If the agency is a new agency retrieve the agency
// document ID and save it to a new agent document
if (globals.newEvent == true) {
String id = _db.collection('event').doc().id;
globals.agencyId = id;
//firestoreService.saveNewEvent(newEvent);
eventProvider.saveEvent();
globals.newEvent = false;
} else {
firestoreService.saveEvent(newEvent);
}
}
}

Answer 1

I found the issue. I just needed to clean up the code.