Flutter下拉选择插件flutter_dropdown_plus的使用
Flutter下拉选择插件flutter_dropdown_plus的使用
flutter_dropdown_plus
是一个用于Flutter应用中的下拉选择插件,支持单选和多选,并且可以进行搜索和自定义。
使用方法
安装
首先,在你的 pubspec.yaml
文件中添加 flutter_dropdown_plus
作为依赖:
dependencies:
flutter:
sdk: flutter
flutter_dropdown_plus:
然后运行 flutter pub get
来安装依赖。
示例代码
以下是一个完整的示例,展示了如何在Flutter应用中使用 flutter_dropdown_plus
插件。
1. 声明变量
List<DropdownItem> _itemList = [];
String _singleSelectedId = ""; // 用于单选下拉菜单
List<String> _multiSelectedIds = []; // 用于多选下拉菜单
final TextEditingController _conDropdownTextField = TextEditingController();
2. 生成项目列表
void _generateItems() {
List<DropdownItem> list = [];
for (int i = 1; i <= 3; i++) {
list.add(DropdownItem(
id: "$i",
value: "Item $i",
data: User(
userId: "$i",
userName: "User $i") // User类是另一个数据类(data字段可以使用任何数据类型)
));
}
setState(() {
_itemList = list;
});
}
3. 在构建函数中放置下拉菜单
单选下拉菜单
Dropdown.singleSelection(
title: "Single Selection Dropdown",
labelText: "Single",
hintText: "Single Selection",
list: _itemList,
selectedId: _singleSelectedId,
isAddItem: true,
onTapAddItem: (searchValue) {
log(searchValue);
},
onSingleItemListener: (selectedItem) {
setState(() {
_singleSelectedId = selectedItem.id;
});
String itemId = selectedItem.id;
String itemName = selectedItem.value;
User user = selectedItem.data as User;
log("Item Id: $itemId -- Item Name: $itemName ## Other Details ## User Id: ${user.userId} -- User Name: ${user.userName}");
}),
多选下拉菜单
Dropdown.multiSelection(
title: "Multi Selection Dropdown",
labelText: "Multi",
hintText: "Multi Selection",
list: _itemList,
selectedIds: _multiSelectedIds,
isAllSelection: true,
isAddItem: true,
onTapAddItem: (searchValue) {
log(searchValue);
},
onMultipleItemListener: (selectedItemList) {
for (DropdownItem selectedItem in selectedItemList) {
String itemId = selectedItem.id;
String itemName = selectedItem.value;
User user = selectedItem.data as User;
log("Item Id: $itemId -- Item Name: $itemName ## Other Details ## User Id: ${user.userId} -- User Name: ${user.userName}");
}
}),
带文本框的下拉菜单
DropdownTextField(
controller: _conDropdownTextField,
list: _itemList,
hintText: "Item search",
labelText: "Item search"
),
完整示例代码
import 'dart:developer';
import 'package:flutter/material.dart';
import 'package:flutter_dropdown_plus/dropdown.dart';
import 'package:flutter_dropdown_plus/dropdown_item.dart';
import 'package:flutter_dropdown_plus/dropdown_textfield.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatefulWidget {
const MyApp({Key? key}) : super(key: key);
@override
State<MyApp> createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> {
@override
Widget build(BuildContext context) {
return const MaterialApp(
debugShowCheckedModeBanner: false, home: DropdownExample());
}
}
class DropdownExample extends StatefulWidget {
const DropdownExample({Key? key}) : super(key: key);
@override
State<DropdownExample> createState() => _DropdownExampleState();
}
class _DropdownExampleState extends State<DropdownExample> {
List<DropdownItem> _itemList = [];
String _singleSelectedId = "";
final List<String> _multiSelectedIds = [];
final TextEditingController _conDropdownTextField = TextEditingController();
@override
void initState() {
super.initState();
_generateItems();
}
void _generateItems() {
List<DropdownItem> list = [];
for (int i = 1; i <= 3; i++) {
list.add(DropdownItem(
id: "$i",
value: "Item $i",
data: User(
userId: "$i",
userName: "User $i") // User类是另一个数据类(data字段可以使用任何数据类型)
));
}
setState(() {
_itemList = list;
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text("flutter_dropdown_plus"),
),
body: SafeArea(
child: SingleChildScrollView(
child: Padding(
padding: const EdgeInsets.all(20),
child: Column(
children: [
Dropdown.singleSelection(
title: "Single Selection Dropdown",
labelText: "Single",
hintText: "Single Selection",
list: _itemList,
selectedId: _singleSelectedId,
isAddItem: true,
onTapAddItem: (searchValue) {
log(searchValue);
},
onSingleItemListener: (selectedItem) {
setState(() {
_singleSelectedId = selectedItem.id;
});
String itemId = selectedItem.id;
String itemName = selectedItem.value;
User user = selectedItem.data as User;
log("Item Id: $itemId -- Item Name: $itemName ## Other Details ## User Id: ${user.userId} -- User Name: ${user.userName}");
}),
const SizedBox(
height: 20,
),
Dropdown.multiSelection(
title: "Multi Selection Dropdown",
labelText: "Multi",
hintText: "Multi Selection",
list: _itemList,
selectedIds: _multiSelectedIds,
isAllSelection: true,
isAddItem: true,
onTapAddItem: (searchValue) {
log(searchValue);
},
onMultipleItemListener: (selectedItemList) {
for (DropdownItem selectedItem in selectedItemList) {
String itemId = selectedItem.id;
String itemName = selectedItem.value;
User user = selectedItem.data as User;
log("Item Id: $itemId -- Item Name: $itemName ## Other Details ## User Id: ${user.userId} -- User Name: ${user.userName}");
}
}),
const SizedBox(
height: 20,
),
DropdownTextField(
controller: _conDropdownTextField,
list: _itemList,
hintText: "Item search",
labelText: "Item search",
),
],
),
),
)),
);
}
}
class User {
String userId;
String userName;
User({this.userId = "0", this.userName = ""});
}
以上是 flutter_dropdown_plus
插件的基本用法和完整示例代码。希望对你有所帮助!
更多关于Flutter下拉选择插件flutter_dropdown_plus的使用的实战系列教程也可以访问 https://www.itying.com/category-92-b0.html
更多关于Flutter下拉选择插件flutter_dropdown_plus的使用的实战系列教程也可以访问 https://www.itying.com/category-92-b0.html
当然,以下是一个关于如何使用 flutter_dropdown_plus
插件的示例代码。这个插件扩展了 Flutter 提供的标准 DropdownButton
,提供了更多功能和更好的用户体验。
首先,确保你已经在 pubspec.yaml
文件中添加了 flutter_dropdown_plus
依赖:
dependencies:
flutter:
sdk: flutter
flutter_dropdown_plus: ^x.y.z # 请替换为最新版本号
然后运行 flutter pub get
以获取依赖。
接下来是一个简单的示例,展示如何在 Flutter 应用中使用 flutter_dropdown_plus
:
import 'package:flutter/material.dart';
import 'package:flutter_dropdown_plus/flutter_dropdown_plus.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Dropdown Plus Example',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(),
);
}
}
class MyHomePage extends StatefulWidget {
@override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
String? selectedValue;
final List<DropdownMenuItemData> dropdownItems = [
DropdownMenuItemData('Option 1'),
DropdownMenuItemData('Option 2'),
DropdownMenuItemData('Option 3'),
];
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Flutter Dropdown Plus Example'),
),
body: Padding(
padding: const EdgeInsets.all(16.0),
child: Column(
children: <Widget>[
DropdownPlus<String>(
data: dropdownItems,
value: selectedValue,
onChanged: (value) {
setState(() {
selectedValue = value;
});
},
searchEnabled: true, // 启用搜索功能
searchDecoration: InputDecoration(
labelText: 'Search...',
border: OutlineInputBorder(),
),
dialogBoxDecoration: BoxDecoration(
color: Colors.white,
borderRadius: BorderRadius.circular(8),
),
itemBuilder: (context, item) {
return ListTile(
leading: Icon(Icons.label),
title: Text(item.value),
);
},
),
SizedBox(height: 20),
Text('Selected Value: $selectedValue'),
],
),
),
);
}
}
// 自定义 DropdownMenuItemData 类,用于存储下拉选项的数据
class DropdownMenuItemData {
final String value;
DropdownMenuItemData(this.value);
}
在这个示例中,我们创建了一个简单的 Flutter 应用,其中包含一个使用 flutter_dropdown_plus
的下拉选择框。以下是一些关键点:
-
DropdownPlus: 使用
DropdownPlus
替代标准的DropdownButton
。它接受一个List<DropdownMenuItemData>
类型的数据列表。 -
searchEnabled: 启用搜索功能,允许用户在下拉列表中搜索选项。
-
searchDecoration: 自定义搜索输入框的装饰。
-
dialogBoxDecoration: 自定义下拉对话框的装饰。
-
itemBuilder: 自定义每个下拉选项的显示样式。
-
DropdownMenuItemData: 自定义数据类,用于存储下拉选项的值。
这个示例展示了 flutter_dropdown_plus
的基本用法,并演示了如何启用搜索功能和自定义下拉选项的显示样式。你可以根据需要进一步自定义和扩展这个示例。