flutter dropdownformfield initial value code example
Example: flutter dropdownbuttonformfield initial value
import 'package:flutter/material.dart';
import '../config/app_theme.dart';
class DropdownWidget extends StatefulWidget {
final String title;
final List items;
final ValueChanged itemCallBack;
final String currentItem;
final String hintText;
DropdownWidget({
this.title,
this.items,
this.itemCallBack,
this.currentItem,
this.hintText,
});
@override
State createState() => _DropdownState(currentItem);
}
class _DropdownState extends State {
List> dropDownItems = [];
String currentItem;
AppTheme appTheme;
_DropdownState(this.currentItem);
@override
void initState() {
super.initState();
for (String item in widget.items) {
dropDownItems.add(DropdownMenuItem(
value: item,
child: Text(
item,
style: TextStyle(
fontSize: 16,
),
),
));
}
}
@override
void didUpdateWidget(DropdownWidget oldWidget) {
if (this.currentItem != widget.currentItem) {
setState(() {
this.currentItem = widget.currentItem;
});
}
super.didUpdateWidget(oldWidget);
}
@override
Widget build(BuildContext context) {
appTheme = AppTheme(Theme.of(context).brightness);
return Container(
margin: EdgeInsets.symmetric(vertical: 10),
child: Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: [
Container(
margin: EdgeInsets.only(left: 6),
child: Text(
widget.title,
style: appTheme.activityAddPageTextStyle,
),
),
Container(
padding: EdgeInsets.symmetric(vertical: 3, horizontal: 15),
margin: EdgeInsets.only(top: 10),
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(6),
color: Colors.white,
boxShadow: [
BoxShadow(
offset: Offset(0, 2),
blurRadius: 10,
color: Color(0x19000000),
),
],
),
child: DropdownButtonHideUnderline(
child: DropdownButton(
icon: appTheme.activityAddPageDownArrowSVG,
value: currentItem,
isExpanded: true,
items: dropDownItems,
onChanged: (selectedItem) => setState(() {
currentItem = selectedItem;
widget.itemCallBack(currentItem);
}),
hint: Container(
child: Text(widget.hintText, style: appTheme.hintStyle),
),
),
),
),
],
),
);
}
}