我有這個下拉串列：
DropdownButtonFormField(
value: shipmentSelected,
hint: Text(
'choose one',
),
onChanged: (value){
shipmentSelected = value;
}
items: product.shipment.map((Shipment shipment) {
return DropdownMenuItem(
value: shipment.code,
child: Text(
shipment.code,
),
);
}).toList(),
)
但它不顯示任何專案......只顯示hintText。如何解決？
uj5u.com熱心網友回復：
您需要onChanged在DropdownButtonFormField構造函式中傳遞一個回呼函式。shipmentSelected從此函式更新和重建，如下所示：
onChanged: (value) {
setState(() {
shipmentSelected = value;
});
},
轉載請註明出處，本文鏈接：https://www.uj5u.com/qukuanlian/330698.html