如何在 Flutter 中显示 DropDownButton？

Question

I want to show dropdownlist/dropdownbutton programmatically, but not show anything. i dont know why not show it. below my code.

           Container(
                height: 200.0,
                child: ListView.builder(
                    scrollDirection: Axis.vertical,
                    shrinkWrap: true,
                  itemCount: _mEmployeeList==null?0:_mEmployeeList.Length,
                    itemBuilder: (context,index)
                        {
                          print(_mEmployeeList[index].EMP_NAME);
                          DropdownButton(
                              items: [
                                DropdownMenuItem(
                                     value:_mEmployeeList[index].EMP_NAME,
                                     child: Text(_mEmployeeList[index].EMP_NAME)
                              ,
                                ),
                              ],
                            // value: _mEmployeeList[index].EMP_NAME,
                            onChanged: (sal){
                                setState(() {
                                  Fhelper.showToast(sal);
                                });
                            },
                          );
                        }
                ),
              ),

Answer 1

Yes, i will solve my problem. thanks

Center( child: Row( children: [ DropdownButton( value:_mEmployeeList[0].EMP_OID, items:_mEmployeeList.map((index) { return DropdownMenuItem( child: new Text(index.EMP_NAME), value: index.EMP_OID, ); }).toList(), onChanged: (sal){ setState(() { Fhelper.showToast(sal); }); }, ), ], ), ),