我已经创建了一个用getx flutter创建了一个自定义的下拉顿布顿，当我用obx包裹时，它会给我带来错误

Question

自定义下拉列表

class CustomDropDown extends StatefulWidget {
PurchasePackageController purchasePackageController =
  PurchasePackageController();
final String hintName;
final List<String> listName;
final void Function(String?)? onChanged;
CustomDropDown(
  {Key? key,
  required this.hintName,
  required this.listName,
  required this.onChanged})
  : super(key: key);

@override
State<CustomDropDown> createState() => _CustomDropDownState();
}

class _CustomDropDownState extends State<CustomDropDown> {
String? selectedValue;

List<DropdownMenuItem<String>> buildDropdownMenuItems(List list) {
List<DropdownMenuItem<String>> dropDownItems = [];
list.forEach((value) {
  dropDownItems.add(DropdownMenuItem<String>(
    value: value,
    child: Padding(
      padding: const EdgeInsets.symmetric(horizontal: 12.0),
      child: Text(
        value,
        style: TextStyle(fontSize: 16.0, color: colorPrimary),
      ),
    ),
  ));
});

return dropDownItems;
}

@override
Widget build(BuildContext context) {
return Padding(
  padding: EdgeInsets.symmetric(horizontal: 10.0.h),
  child: InputDecorator(
    decoration: InputDecoration(
      enabledBorder: UnderlineInputBorder(
        borderSide: BorderSide(color: colorPrimary),
      ),
    ),
    isEmpty: true,
    //dropdownvalue == '',
    child: DropdownButtonHideUnderline(
      child: Obx(() => DropdownButton<String>(
            iconSize: 30.0.sp,
            iconEnabledColor: colorPrimary,
            hint: Padding(
              padding: EdgeInsets.symmetric(horizontal: 12.0.h),
              child: Text(
                widget.hintName,
                style: TextStyle(fontSize: 18.0.sp, color: colorPrimary),
              ),
            ),
            value: selectedValue,
            isDense: true,
            onChanged: (value) => widget.onChanged,
            buildDropdownMenuItems() 
            items: buildDropdownMenuItems(
              widget.listName,
            ),
          )),
    ),
  ),
);
}
}

视图

class LocationView extends GetView<LocationController> {


LocationView({Key? key}) : super(key: key);
@override
Widget build(BuildContext context) {
return Scaffold(
    appBar: AppBar(
      title: const Text('Location'),
      centerTitle: true,
    ),
    body: Column(
      children: [
        CustomDropDown(
          hintName: "Package Type",
          listName: controller.MDPackageType,
          onChanged: (newValue) =>
              controller.onChangedPackageName(newValue!),
        ),
        CustomDropDown(
            hintName: "Package Name",
            listName: controller.MDPackageType,
            onChanged: (newValue) =>
                controller.onChangedPackageType(newValue!)),
        Container(
          height: MediaQuery.of(context).size.height * 0.50,
          width: MediaQuery.of(context).size.width * 0.95,
          child: Column(children: [
            Text(controller.selectedPackageName.value),
            Text(controller.selectedPackageType.value)
          ]),
        )
      ],
    ));
}

}

控制器

class LocationController extends GetxController {


List<String> MDPackageType = [
'Package Type 1',
'Package Type 2',
'Package Type 3',
'Package Type 4',
];
List<String> MDPackageName = [
'Package Name 1',
'Package Name 2',
'Package Name 3',
'Package Name 4',
];
var selectedPackageType = "Package Type 1".obs;
var selectedPackageName = "Package Name 1".obs;

onChangedPackageType(String value) => selectedPackageType.value = value;
onChangedPackageName(String value) => selectedPackageName.value = value;
}

错误

投掷“” [GET]检测到GetX的不当使用。 您只能将GETX或OBX用于将要更新的特定小部件。 如果您看到此错误，您可能没有将任何可观察的变量插入GetX/obx 或将它们插入getx认为适合更新的范围之外 （示例：getx =＆gt; heidewidget =＆gt; variable observable）。 如果您需要更新父窗口小部件和子小部件，请将每个小部件包装在OBX/GETX中。 ”“”; }

并且，如果我删除了OBX，则可以代码正在运行，但我不能选择“ frrom”下拉菜单

Answer 1

固定的！！！

必须更改

onChanged: (value) => widget.onChanged,

并

onChanged: (value) {
          setState(() {
            selectedValue = value;
          });
          if (widget.onChanged != null) widget.onChanged!(value);
        },

删除OBX