Question

我有以下代码将一堆复选框放在 dropDownMenu 中此代码在空安全之前运行良好，但现在显示一些错误

ActivityType dropdownValue = ActivityType(activityTypeName: "hell", id: 1);

List<ActivityType> activityList = [
ActivityType(activityTypeName: "hell", id: 1),
ActivityType(activityTypeName: "para", id: 2)
];
List<ActivityType> selectedCheckBoxItems1 = [];

DropdownButtonHideUnderline(
              child: DropdownButton(
            value: dropdownValue,
            onChanged: (dynamic val) {},
            icon: Icon(Icons.arrow_drop_down),
            iconSize: 24,
            items: activityList
                .map((e) => DropdownMenuItem(
                        child: Container(
                      width: MediaQuery.of(context).size.width / 2,
                      child: StatefulBuilder(
                        builder:
                            (BuildContext context, StateSetter setState) {
                          return CheckboxListTile(
                              title: Text(e.activityTypeName ?? ""),
                              value: selectedCheckBoxItems1.indexWhere(
                                          (element) =>
                                              element.activityTypeName ==
                                              e.activityTypeName) >=
                                      0
                                  ? true
                                  : false,
                              onChanged: (value) {
                                setSelectedCheckBox1(e, value!);
                                setState(() {});
                              });
                        },
                      ),
                    )))
                .toList(),
          ))

<块引用> <块引用>

以下断言被抛出构建 testDrop(dirty, dependencies: [MediaQuery], state: _testDropState#146a8): There should 恰好是具有 [DropdownButton] 值的一项：Instance of '活动类型'。零个或 2 个或更多 [DropdownMenuItem] 是检测到相同的值 'package:flutter/src/material/dropdown.dart'：失败的断言：行 850 pos 15: 'items == null || items.isEmpty ||值 == 空 || items.where((DropdownMenuItem item) { 返回 item.value == 值； }).length == 1'

颤动中带有复选框错误的下拉菜单

0 个答案: