我想为这个小部件中的局部变量分配一个日期值并显示在文本框中

这样做的原因是它不是一个有状态的小部件，在长度上我更新为一个有状态的小部件，并在更新发生时将 k 作为局部变量和 setState

class Fdate extends StatefulWidget {
  @override
  _FdateState createState() => _FdateState();
}

class _FdateState extends State<Fdate> {
  String k ='Select Date';
  DateTime selectedDate = DateTime.now();
  void setDate(String date){
    setState(() {
        k = date;
    });
  }
  @override
  Widget build(BuildContext context) {
    return  Column(
      children: [

        Container(

            padding: EdgeInsets.zero,
            margin: EdgeInsets.all(0),
            // color: Colors.black87,
            child:
            Align(
              alignment: Alignment.centerLeft,
              child: Text("Select Date",style: TextStyle(fontSize: 14.sp,fontWeight: FontWeight.w400,fontFamily:'OpenSans',),),
            )
        ),
        Container(
          // color: Colors.blue,
          margin: EdgeInsets.only(top:0),

          // color: Colors.blue,
          child: Align(
            alignment: Alignment.centerLeft,
            child: GestureDetector(
              onTap: () async {
                final DateTime picked = await showDatePicker(
                  context:context ,
                  initialDate: DateTime.now(),
                  firstDate: DateTime(2001),
                  lastDate: DateTime(2200),
                  // initialEntryMode: DatePickerEntryMode.input,

                );
                setDate(picked.toIso8601String().split('T').first);


              },
              child: Container(
                // height:40.h,
                height: MediaQuery.of(context).size.height*0.050,
                child: DropdownButton(

                  icon: Container(
                      alignment: Alignment.centerLeft,
                      // color: Colors.blueGrey,
                      padding: EdgeInsets.zero,
                      margin: EdgeInsets.only(left: MediaQuery.of(context).size.width*0.25),
                      child: IconButton(
                        icon:Icon(Icons.arrow_drop_down,size:25.w,),
                        color: Colors.black87,
                        padding: EdgeInsets.all(0),
                        constraints: BoxConstraints(),

                        onPressed: (){
                          // print("Hello");
                          // showDatePicker(
                          //   context:context ,
                          //   initialDate: DateTime.now(),
                          //   firstDate: DateTime(2001),
                          //   lastDate: DateTime(2200),
                          // ).then((pickedDate) => print(pickedDate));
                        },

                      )),
                  hint:Container(
                    // color: Colors.red,
                      child: Text(k,style: TextStyle(fontSize: 14.sp,fontWeight: FontWeight.bold,color:Colors.black87,fontFamily:'OpenSans'),)),

                ),
              ),
            ),
          ),
        )
      ],
    );
  }
}