how to link flutter with firebase? - firebase

Question

I am a flutter programmer and I want to learn Firebase and link it to flutter, now I was able to create the following code that allows the user to add the number of units he wants, so that every time he enters the name of the unit and chooses its number, then it sends all the information to Firebase How do I complete this code so that the user can send the information he entered to Firebase?
My code
class _UnitesPageState extends State<UnitesPage> with TickerProviderStateMixin {
var _myWidgets = <Widget>[];
int _index = 0;
final unitesnumber = [
' unite 1 ',' unite 2 ',' unite 3 ',
];
bool autoValidate = true;
GlobalKey<FormBuilderState> _formKey = GlobalKey<FormBuilderState>();
final Map<int, String> namesvalues = Map();
final Map<int, String> unitesvalues = Map();
final List<TextEditingController> _namesControllers = [];
final List<TextEditingController> _unitesControllers = [];
void _add() {
int keyValue = _index;
_myWidgets = List.from(_myWidgets)
..add(Container(
child: Column(
children: <Widget>[
_names(keyValue),
_unites(keyValue),
],
),
));
setState(() => ++_index);
}
#override
Widget build(BuildContext context) {
final bottomNavigationBar = Container(
child: Row(
children: <Widget>[
FlatButton.icon(
label: const Text(' SEND',
)),
onPressed: () async {
setState(() {
autoValidate = !autoValidate;
});
for (var i = 0; i < _myWidgets.length; i++) {
Map<String, dynamic> data = {
"Widgets Number":_myWidgets.length,
"names": _namesControllers[i].text,
"unites":_unitesControllers[i].text,
};
}
}
),
],
),
);
return Scaffold(
// appBar
bottomNavigationBar: bottomNavigationBar,
body:Padding(
child: Form(
autovalidateMode: AutovalidateMode.disabled,
key: _formKey,
child: Stack(
children: <Widget>[
Column(
children: <Widget>[
_buildfaculte(),
Expanded(
child: SizedBox(
child: ListView(
addAutomaticKeepAlives: true,
children: _myWidgets,
),
),
),
],
)
],
),),
),
);
}
Widget _names(int keyValue) {
TextEditingController controller = TextEditingController();
_namesControllers.add(controller);
return FormBuilderTextField(
name: 'names',
controller: controller,
);
}
Widget _unites(int keyValue) {
TextEditingController controller = TextEditingController();
_unitesControllers.add(controller);
return Container(
alignment: Alignment.center,
child: Autocomplete<String>(
optionsBuilder: (TextEditingValue value) {
return unitesnumber.where((suggestion) =>
suggestion.toLowerCase().contains(value.text.toLowerCase()));
},
onSelected: (value) {
setState(() {
_selectedUnites = value;
});
},
),
);
}
}