DropdownButtonFormField 不显示所选颤振的值

Question

这是我的代码，我试图在我的控制台中打印值，以确定它是否工作并且正确打印，但它没有显示在文本字段中。当我选择提示时文本消失了，但是什么也没有显示我还改变了图标(箭头)的大小但是当我点击它的任何部分时，没有反应直到我点击角落

String _medicationDesc;
List<DropdownMenuItem> getDropDownItem() {
List<DropdownMenuItem> dropDownItems = [];
for (String dose in medcationDose) {
var newItem = DropdownMenuItem(
child: Text(
dose,
style: textStyle1,
),
value: dose,
);
dropDownItems.add(newItem);
}
return dropDownItems;
}
List<String> medcationDose = [
'مرة واحدة في اليوم',
'مرتان في اليوم',
'ثلاث مرات في اليوم',
'اربعة مرات في اليوم',
'وقت الحاجة'
];
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(backgroundColor: nave),
body: SingleChildScrollView(
child: Container(
margin: EdgeInsets.fromLTRB(0.0, 30, 0, 0),
child: Column(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
Column(
children: [
SizedBox(
height: 50,
width: 350,
child: DropdownButtonFormField(
value: _medicationDose,
items: getDropDownItem(),
iconSize: 50,
iconEnabledColor: white,
onChanged: (value) {
setState(() {
_medicationDose = value;
});
},
decoration: InputDecoration(
hintText: 'الجرعة',
),
),

Answer 1

try this

List<String> languageList = ['EN', 'ES', 'FR'];
var selectedValue;
DropdownButtonHideUnderline(
child: DropdownButtonFormField<String>(
decoration: InputDecoration(
enabledBorder: UnderlineInputBorder(
borderSide: BorderSide(color: Colors.transparent))),
dropdownColor: CustomColors.black,
value:
selectedValue == null ? languageList[0] : selectedValue,
style: robotoStyle(
color: CustomColors.white,
fontSize: 10),
icon: Icon(
Icons.keyboard_arrow_down,
color: CustomColors.white,
),
isExpanded: true,
items: languageList.map((item) {
return DropdownMenuItem<String>(
value: item,
child: new Text(item,
style: robotoStyle(
color: CustomColors.white,
fontSize: 10)),
);
}).toList(),
onChanged: (value) {
selectedValue = value;
S.load(Locale(selectedValue));
print(selectedValue);
},
),
)

Answer 2

我为你创建了一个类，你可以在任何地方调用它，也许它会对你有帮助

class DropDownClass extends StatelessWidget {
var values;
var hint;
List list = new List();
Color underLineColor;
Color dropDownColor;
Color textColor;
DropDownClass({this.values, 
this.list,this.hint,this.underLineColor,this.dropDownColor,this.textColor});
@override
Widget build(BuildContext context) {
return DropdownButtonHideUnderline(
child: DropdownButtonFormField<String>(
value: values,
dropdownColor: dropDownColor??Colors.white,
decoration: InputDecoration(
enabledBorder: UnderlineInputBorder(
borderSide: BorderSide(
color: underLineColor??Colors.grey[800],
width: 1.0,
),
)
),
style: TextStyle(
color: textColor??Colors.black,
fontWeight: FontWeight.w400,
fontSize: 15),
isExpanded: true,
icon: Icon(
Icons.keyboard_arrow_down,
color: Colors.white,
),
hint: Text(hint,
style: TextStyle(
color:Colors.white,
fontWeight: FontWeight.w400,
fontSize:15)),
items: list.map((item) {
return DropdownMenuItem<String>(
value: item,
child: new Text(item,
style: TextStyle(
color:Colors.black,
fontWeight: FontWeight.w400,
fontSize:15)),
);
}).toList(),
onChanged: (value) {
values = value;
print(values);
},
),
);

}}