DateTime becomes null when I send to Firestore - flutter

Question

I have created a TextFormField to send DateTime to a firestore collection, but when I send the information it gets a null field on "datasaida":
This is the code:
class AddSaida extends StatefulWidget {
AddSaida({Key? key}) : super(key: key);
#override
State<AddSaida> createState() => _AddSaidaState();
}
class _AddSaidaState extends State<AddSaida> {
String? valorsaida,nomesaida,datasaida;
getSaidaValue(valorsaida){
this.valorsaida=valorsaida;
}
getSaidaName(nomesaida){
this.nomesaida=nomesaida;
}
getSaidaDate(datasaida){
this.datasaida=datasaida;
}
createData(){
DocumentReference ds=FirebaseFirestore.instance.collection('addsaidas').doc(nomesaida);
Map<String,dynamic> tasks={
"valorsaida":valorsaida,
"nomesaida":nomesaida,
"datasaida":datasaida,
"tipocategoria":categVal,
};
ds.set(tasks).whenComplete((){
print("task updated");
});
}
var saidanamecontroller = TextEditingController();
var saidadatecontroller = TextEditingController();
var saidavaluecontroller = TextEditingController();
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
backgroundColor: Color.fromARGB(255, 92, 172, 178),
centerTitle: true,
title: Text('Adicionar saída'),
toolbarHeight: 90,
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(40)
),
elevation: 15,
),
body:
SingleChildScrollView(
child: Container(
padding: const EdgeInsets.all(28),
child: Column(
children: [
TextFormField(
controller: saidanamecontroller,
onChanged: (String nomesaida){
getSaidaName(nomesaida);
},
autofocus: true,
decoration: InputDecoration(
contentPadding: EdgeInsets.fromLTRB(12, 0, 12, 0),
hintText: "Nome da saída",
hintStyle: TextStyle(color: Color.fromARGB(255, 138, 136, 136),
fontSize: 18),
prefixIcon: Icon(
Icons.label_important_outline,
color: Color.fromARGB(255, 92, 172, 178),
size: 30,
),
labelText: "Nome da saída",
labelStyle: TextStyle(color: Color.fromARGB(255, 136, 136, 136), fontFamily: 'PathwayGothicOne', fontSize: 13),
),
SizedBox(height: 20),
TextFormField(
controller: saidadatecontroller,
onChanged: (datasaida){
getSaidaName(datasaida);
},
autofocus: true,
decoration: InputDecoration(
contentPadding: EdgeInsets.fromLTRB(12, 0, 12, 0),
hintStyle: TextStyle(color: Color.fromARGB(255, 138, 136, 136),
fontSize: 18),
prefixIcon: Icon(
Icons.calendar_month_outlined,
color: Color.fromARGB(255, 92, 172, 178),
size: 30,
),
labelText: "Data da saída",
labelStyle: TextStyle(color: Color.fromARGB(255, 136, 136, 136), fontFamily: 'PathwayGothicOne', fontSize: 13),
enabledBorder: UnderlineInputBorder(
borderSide: BorderSide(
color: Color.fromARGB(153, 191, 190, 190),
),
),
focusedBorder: UnderlineInputBorder(
borderSide: BorderSide(
color: Color.fromARGB(153, 191, 190, 190),
),
),
),
onTap: () async {
DateTime? pickeddate = await showDatePicker(
context: context,
initialDate: DateTime.now(),
firstDate: DateTime(2022),
lastDate: DateTime(2036));
if (pickeddate != null) {
saidadatecontroller.text = DateFormat('dd-MM-yyyy').format(pickeddate);
}
},
The other fields are working correctly, this is the only one getting a null value. I have tried to transform the value to a String, but i couldn't.
I don't know how to fix this, please help!

Answer 1

You are getting this behavior because datasaida is null before setting it into the firestore document.
You are setting datasaida only on the onChanged event but it also needs to be set on the onTap event also so that it cannot be null across all Datepicker events even at empty value it will have "" string.
Here I have tested on singular TextFormField of type DateTime :
class AddSaida extends StatefulWidget {
const AddSaida({Key? key}) : super(key: key);
#override
State<AddSaida> createState() => _AddSaidaState();
}
class _AddSaidaState extends State<AddSaida> {
final _dateController = TextEditingController();
String? datasaida;
getSaidaName(datasaida) {
this.datasaida = datasaida;
}
createData() {
if (datasaida != null) {
DocumentReference ds = FirebaseFirestore.instance
.collection('addsaidas')
.doc("cnFxQ8wRivY39EywI3TS"); //just a existing docId
Map<String, dynamic> tasks = {
"datasaida": datasaida,
};
ds.set(tasks).whenComplete(() {
print("task updated");
});
}
}
#override
Widget build(BuildContext context) {
return Scaffold(
body: Column(
children: [
TextFormField(
controller: _dateController,
decoration: const InputDecoration(
labelText: 'Date',
),
onTap: () async {
DateTime? pickedDate = await showDatePicker(
context: context,
initialDate: DateTime.now(),
firstDate: DateTime(2022),
lastDate: DateTime(2036),
);
if (pickedDate != null) {
_dateController.text =
DateFormat('dd-MM-yyyy').format(pickedDate);
getSaidaName(DateFormat('dd-MM-yyyy').format(pickedDate)); // ⇐ Notice
}
},
onChanged: (value) {
getSaidaName(value);
},
),
ElevatedButton(
onPressed: createData,
child: const Text('Save Date'),
),
],
),
);
}
}