[英]Why do I get a type error in flutter while using DropdownButton with selectedItemBuilder and hint?
同時使用 selectedBuilder 和提示時,我收到以下錯誤:
類型“DefaultTextStyle”不是“值”的“文本”類型的子類型
以下是我在代碼中使用的代碼片段:
final Map<String, String> _items = [
{
'name': "India",
'code': "+91",
},
];
Map<String, String> _seletedValue;
DropdownButtonFormField(
selectedItemBuilder: (_) {
return _items
.map(
(country) => Text(
"${country['name']} (${country['code']})",
style: TextStyle(
color: Colors.black,
),
),
)
.toList();
},
dropdownColor: Color(0xFF4C4F89),
style: TextStyle(
color: Colors.white,
),
items: _items
.map(
(country) => DropdownMenuItem(
child: Text(
"${country['name']} (${country['code']})",
style: TextStyle(
color: Colors.white,
),
),
value: country,
),
)
.toList(),
onChanged: (value) {
setState(() {
_seletedValue = value;
});
},
hint: Text('Select your country'),
)
有人可以建議一些更正來解決這個錯誤嗎?
我認為您需要將列表項轉換為小部件
selectedItemBuilder: (_) {
return _items
.map<Widget>( // Casting
(country) => Text(
"${country['name']} (${country['code']})",
style: TextStyle(
color: Colors.black,
),
),
)
.toList();
},
希望有效!
參考: https : //api.flutter.dev/flutter/material/DropdownButton/selectedItemBuilder.html
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