Question

这是我的代码

SearchableDropdown.single(

isExpanded: true,
hint: 'Choose country',
value: countrySeleted,
selectedValueWidgetFn: (val) {
return Text(countrySeleted.name);
},
dialogBox: true,
items: countries.map((e) =>
DropdownMenuItem(child: Text(e.name)))
.toList(),
onChanged: (value) {

setState(() {
countrySeleted = value;
});
},
)

<块引用>

选择项目时，此值始终为空

Flutter Searchable dropwn 下拉选择值始终返回 null

依赖：searchable_dropdown：^1.1.3

Answer 1

“items”的“value”标签丢失，这就是它返回 null 的原因。为项目提供价值可能会解决此错误。尝试以下代码：

                            SearchableDropdown.single(
                              isExpanded: true,
                              hint: 'Choose country',
                              value: countrySeleted,
                              selectedValueWidgetFn: (val) {
                                return Text(countrySeleted.name);
                              },
                              dialogBox: true,
                              items: countries.map((e) =>
                                  DropdownMenuItem(child: Text(e.name),
                                  value: e,)
                                    )
                                  .toList(),

                            onChanged: (value) {

                              setState(() {
                                countrySeleted = value;
                              });
                            },
                              )

Flutter Searchable dropwn 下拉选择值始终返回 null

1 个答案: