how to get flutter textfield value to datepicker - flutter

Question

When I enter date in text field in "MM/dd/yyyy" than how to assign same value to date picker
Stack(
alignment: Alignment.centerRight,
children: [
TextFormField(
controller: birthDateInputController,
validator: Utils.birthDateValidator,
inputFormatters: [
FilteringTextInputFormatter.singleLineFormatter,
birthDateInput,
],
),
IconButton(
icon: Icon(
Icons.calendar_today_rounded,
),
onPressed: () async {
FocusScope.of(context).requestFocus(FocusNode());
DateTime pickedDate = await showDate();
if (pickedDate != null) {
setState(() {
intl.DateFormat formatter =
intl.DateFormat('MM/dd/yyyy');
String formatted = formatter.format(pickedDate);
birthDateInputController.text = formatted;
birthDate = pickedDate;
});
}
},
),
],
),
Future<DateTime> showDate() async {
return await showDatePicker(
context: context,
initialDate: DateTime.now(),
firstDate: DateTime(1920),
lastDate: DateTime.now(),
);
}
and When I select value to date picker than assign to the text field
but when I enter date in text field than can't assign to the date picker

Answer 1

For Assign to DatePicker. you need to add couple of things in Future<DateTime> showDate(String dateTime)
Future<DateTime> showDate(String dateTime) async {
DateTime _dateTime;
if (dateTime.isNotEmpty) {
_dateTime = DateFormat('MM/dd/yyyy').parse(dateTime);
} else {
_dateTime = DateTime.now();
}
return await showDatePicker(
context: context,
initialDate: _dateTime,
firstDate: DateTime(1920),
lastDate: DateTime.now(),
);
}
Pass your text in this showDate() Method in onPressed
onPressed: () async {
FocusScope.of(context).requestFocus(FocusNode());
DateTime pickedDate = await showDate(birthDateInputController.text);
if (pickedDate != null) {
setState(() {
intl.DateFormat formatter =
intl.DateFormat('MM/dd/yyyy');
String formatted = formatter.format(pickedDate);
birthDateInputController.text = formatted;
birthDate = pickedDate;
});
}
},
And in TextFormField you only have to pass the number and forward slash for that
TextFormField(
controller: birthDateInputController,
validator: Utils.birthDateValidator,
keyboardType: TextInputType.datetime, // use this parameter
inputFormatters: [
FilteringTextInputFormatter.singleLineFormatter,
FilteringTextInputFormatter.allow(RegExp('[0-9/]')), // for numbers only
LengthLimitingTextInputFormatter(10), //set the number limit including slash
birthDateInput,
],
),
Make a validation which the date is correct format when typing

Answer 2

In your showDate() function you used initialDate: DateTime.now() which take the todays date as initial date
So now you should set the initialDate as manually
Try to implement showDate() method like
Future<DateTime> showDate(int year, int month, int day, int hr, int min, int sec) async {
return await showDatePicker(
context: context,
initialDate: DateTime(year, month, day, hr, min, sec),
firstDate: DateTime(1920),
lastDate: DateTime.now(),
);
}