I created dropdown in TextFormField in flutter, i successfully loaded list (bankDataList) into dropdown which is dynamic list. Data is showing into dropdown list. But i have a problem to assign "value : _bankChoose" into DropDownButton , it is not updating into TextFormField. I am using icon and text, please see screenshot.
  String _bankChoose;
   List<BankListDataModel> bankDataList;
      Container(
                  margin: EdgeInsets.only(left: 15, top: 10, right: 15),
                    child: FormField<String>(
                      builder: (FormFieldState<String> state) {
                        return InputDecorator(
                          decoration: InputDecoration(
                              contentPadding:
                                  EdgeInsets.fromLTRB(12, 10, 20, 20),
                              // labelText: "hi",
                              // labelStyle: textStyle,
                              // labelText: _dropdownValue == null
                              //     ? 'Where are you from'
                              //     : 'From',
                              errorText: _errorBank,
                              errorStyle: TextStyle(
                                  color: Colors.redAccent, fontSize: 16.0),
                              border: OutlineInputBorder(
                                  borderRadius:
                                      BorderRadius.circular(10.0))),
                          child: DropdownButtonHideUnderline(
                            child: DropdownButton<BankListDataModel>(
                              style: TextStyle(
                                fontSize: 16,
                                color: text_gray_color,
                                fontFamily: "verdana_regular",
                              ),
                              hint: Text(
                                "Select Bank",
                                style: TextStyle(
                                  color: text_gray_color,
                                  fontSize: 16,
                                  fontFamily: "verdana_regular",
                                ),
                              ),
                              value: _bankChoose,
                              isExpanded: true,
                              isDense: true,
                              onChanged: (BankListDataModel newValue) {
                                setState(() {
                                  _bankChoose = newValue.bank_name;
                                });
                              },
                              items: bankDataList
                                  .map<DropdownMenuItem<BankListDataModel>>(
                                      (BankListDataModel valueItem) {
                                return DropdownMenuItem(
                                  value: valueItem,
                                  child: Row(
                                    // mainAxisAlignment: MainAxisAlignment.spaceBetween,
                                    children: [
                                      new CircleAvatar(
                                        backgroundImage: new NetworkImage(
                                            valueItem.bank_logo),
                                      ),
                                      // Icon(valueItem.bank_logo),
                                      SizedBox(
                                        width: 15,
                                      ),
                                      Text(valueItem.bank_name),
                                    ],
                                  ),
                                );
                              }).toList(),
                            ),
                          ),
                        );
                      },
                    ),
                  ),
