Flutter 如何使用ListTile记住并突出显示选定的抽屉项目?
我正在使用ListTile在导航抽屉上显示项目,但我很难创建isSelected颜色,并已使用此颜色将其应用于onTap,但不断出现索引错误,应用程序无法识别onTap上的isSelected颜色:Flutter 如何使用ListTile记住并突出显示选定的抽屉项目?,flutter,listview,colors,navigation,drawer,Flutter,Listview,Colors,Navigation,Drawer,我正在使用ListTile在导航抽屉上显示项目,但我很难创建isSelected颜色,并已使用此颜色将其应用于onTap,但不断出现索引错误,应用程序无法识别onTap上的isSelected颜色: for(int i = 0; i < isSelected.length; i++){ setState(() { if (index == i) {
for(int i = 0; i < isSelected.length; i++){
setState(() {
if (index == i) {
isSelected[index] = true;
} else { //the condition to change the highlighted item
isSelected[i] = false;
}
});
for(int i=0;i
这是我创建的Flatter中的导航抽屉,如果你能给出建议,如何在_createDrawerItem小部件中获取“isSelected”并将其应用于抽屉。我已经将抽屉项的“isSelected”设置为true和false,但似乎无法将其应用于onTap
class NavDraw extends StatefulWidget {
@override
_NavDrawState createState() => _NavDrawState();
}
class _NavDrawState extends State<NavDraw> {
@override
void initState() {
super.initState();
}
Widget build(BuildContext context) {
return Drawer(
child: Container(
child: ListView(
children: <Widget> [
Container(
height: 100.0,
color: Color(0xff2B4DB9),
child: DrawerHeader(
margin: EdgeInsets.fromLTRB(0, 0, 0, 0),
padding: EdgeInsets.zero,
decoration: BoxDecoration(
image: DecorationImage(
fit: BoxFit.none,
image: AssetImage('images/drawer_header.png')))),
),
_createDrawerItem(
icon: Icons.timer,
text: 'Timer',
isSelected: true,
onTap: () =>
Navigator.pushReplacementNamed(context, Routes.home)),
_createDrawerItem(
icon: Icons.history,
text: 'History',
isSelected: false,
onTap: () =>
Navigator.pushReplacementNamed(context, Routes.history)),
_createDrawerItem(
icon: Icons.help,
text: 'Help & Support',
isSelected: false,
onTap: () =>
Navigator.pushReplacementNamed(context, Routes.help_and_support)),
_createDrawerItem(
icon: Icons.rate_review,
text: 'Write a Review',
isSelected: false,
onTap: () =>
Navigator.pushReplacementNamed(context, Routes.write_a_review)),
Divider(),
],
),
),
);
}
}
Widget _createDrawerItem(
{IconData icon, String text, GestureTapCallback onTap, bool isSelected}) {
return Ink(
color: isSelected ? Color(0xffE3EAFF) : Colors.transparent,
child: ListTile(
selected: true,
hoverColor: Colors.white,
title: Row(
children: <Widget>[
Icon(icon),
Padding(
padding: EdgeInsets.only(left: 8.0),
child: Text(text),
)
],
),
onTap: onTap,
),
);
}
类NavDraw扩展StatefulWidget{
@凌驾
_NavDrawState createState();
}
类_NavDrawState扩展状态{
@凌驾
void initState(){
super.initState();
}
小部件构建(构建上下文){
回程抽屉(
子:容器(
子:ListView(
儿童:[
容器(
高度:100.0,
颜色:颜色(0xff2B4DB9),
儿童:抽屉阅读器(
边距:从LTRB(0,0,0,0)开始的边距集,
填充:EdgeInsets.zero,
装饰:盒子装饰(
图像:装饰图像(
适合:BoxFit.none,
image:AssetImage('images/drawer\u header.png'),
),
_创造者(
图标:Icons.timer,
文本:“计时器”,
是的,
onTap:()=>
Navigator.pushReplacementNamed(上下文,Routes.home)),
_创造者(
图标:Icons.history,
正文:“历史”,
选:错,
onTap:()=>
Navigator.pushReplacementNamed(上下文,Routes.history)),
_创造者(
icon:Icons.help,
文本:“帮助和支持”,
选:错,
onTap:()=>
Navigator.pushReplacementNamed(上下文、Routes.help和支持)),
_创造者(
图标:Icons.rate_review,
文字:“写一篇评论”,
选:错,
onTap:()=>
Navigator.pushReplacementNamed(上下文,Routes.write_a_review)),
分隔符(),
],
),
),
);
}
}
小部件_createDrawerItem(
{IconData图标、字符串文本、GestureTapCallback onTap、布尔isSelected}){
回墨(
颜色:isSelected?颜色(0xffE3EAFF):颜色。透明,
孩子:ListTile(
选择:正确,
hoverColor:Colors.white,
标题:世界其他地区(
儿童:[
图标(图标),
填充物(
填充:仅限边缘设置(左:8.0),
子:文本(Text),
)
],
),
onTap:onTap,
),
);
}
您可以复制粘贴运行下面的完整代码您可以使用
selectedIndex
来控制在
isSelected
passselectedIndex==0
或selectedIndex==1
。等代码片段
int selectedIndex = 0;
...
_createDrawerItem(
icon: Icons.timer,
text: 'Timer',
isSelected: selectedIndex == 0,
onTap: () {
setState(() {
selectedIndex = 0;
});
Navigator.pushReplacementNamed(context, "/page0");
}),
工作演示
完整代码
import 'package:flutter/material.dart';
class NavDraw extends StatefulWidget {
@override
_NavDrawState createState() => _NavDrawState();
}
int selectedIndex = 0;
class _NavDrawState extends State<NavDraw> {
@override
Widget build(BuildContext context) {
return Drawer(
child: Container(
child: ListView(
children: <Widget>[
Container(
height: 100.0,
color: Color(0xff2B4DB9),
child: DrawerHeader(
margin: EdgeInsets.fromLTRB(0, 0, 0, 0),
padding: EdgeInsets.zero,
decoration: BoxDecoration(
image: DecorationImage(
fit: BoxFit.none,
image: NetworkImage(
'https://picsum.photos/250?image=9')))),
),
_createDrawerItem(
icon: Icons.timer,
text: 'Timer',
isSelected: selectedIndex == 0,
onTap: () {
setState(() {
selectedIndex = 0;
});
Navigator.pushReplacementNamed(context, "/page0");
}),
_createDrawerItem(
icon: Icons.history,
text: 'History',
isSelected: selectedIndex == 1,
onTap: () {
setState(() {
selectedIndex = 1;
});
Navigator.pushReplacementNamed(context, "/page1");
}),
_createDrawerItem(
icon: Icons.help,
text: 'Help & Support',
isSelected: selectedIndex == 2,
onTap: () {
setState(() {
selectedIndex = 2;
});
Navigator.pushReplacementNamed(context, "/page2");
}),
_createDrawerItem(
icon: Icons.rate_review,
text: 'Write a Review',
isSelected: selectedIndex == 3,
onTap: () {
setState(() {
selectedIndex = 3;
});
Navigator.pushReplacementNamed(context, "/page3");
}),
Divider(),
],
),
),
);
}
}
Widget _createDrawerItem(
{IconData icon, String text, GestureTapCallback onTap, bool isSelected}) {
return Ink(
color: isSelected ? Color(0xffE3EAFF) : Colors.transparent,
child: ListTile(
selected: true,
hoverColor: Colors.white,
title: Row(
children: <Widget>[
Icon(icon),
Padding(
padding: EdgeInsets.only(left: 8.0),
child: Text(text),
)
],
),
onTap: onTap,
),
);
}
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
visualDensity: VisualDensity.adaptivePlatformDensity,
),
initialRoute: '/page0',
routes: {
'/page0': (context) => Page0(),
'/page1': (context) => Page1(),
'/page2': (context) => Page2(),
'/page3': (context) => Page3(),
},
);
}
}
class Page0 extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
drawer: NavDraw(),
appBar: AppBar(
title: Text("page 0"),
),
body: Text("page 0"));
;
}
}
class Page1 extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
drawer: NavDraw(),
appBar: AppBar(
title: Text("page 1"),
),
body: Text("page 1"));
;
}
}
class Page2 extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
drawer: NavDraw(),
appBar: AppBar(
title: Text("page 2"),
),
body: Text("page 2"));
;
}
}
class Page3 extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
drawer: NavDraw(),
appBar: AppBar(
title: Text("page 3"),
),
body: Text("page 3"));
;
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
@override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
int _counter = 0;
void _incrementCounter() {
setState(() {
_counter++;
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
drawer: NavDraw(),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text(
'You have pushed the button this many times:',
),
Text(
'$_counter',
style: Theme.of(context).textTheme.headline4,
),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: Icon(Icons.add),
),
);
}
}
导入“包装:颤振/材料.省道”;
类NavDraw扩展StatefulWidget{
@凌驾
_NavDrawState createState();
}
int selectedIndex=0;
类_NavDrawState扩展状态{
@凌驾
小部件构建(构建上下文){
回程抽屉(
子:容器(
子:ListView(
儿童:[
容器(
高度:100.0,
颜色:颜色(0xff2B4DB9),
儿童:抽屉阅读器(
边距:从LTRB(0,0,0,0)开始的边距集,
填充:EdgeInsets.zero,
装饰:盒子装饰(
图像:装饰图像(
适合:BoxFit.none,
图片:NetworkImage(
'https://picsum.photos/250?image=9')))),
),
_创造者(
图标:Icons.timer,
文本:“计时器”,
isSelected:selectedIndex==0,
onTap:(){
设置状态(){
selectedIndex=0;
});
Navigator.pushReplacementNamed(上下文,“/page0”);
}),
_创造者(
图标:Icons.history,
正文:“历史”,
isSelected:selectedIndex==1,
onTap:(){
设置状态(){
selectedIndex=1;
});
Navigator.pushReplacementNamed(上下文,“/page1”);
}),
_创造者(
icon:Icons.help,
文本:“帮助和支持”,
isSelected:selectedIndex==2,
onTap:(){
设置状态(){
选择指数=2;
});
Navigator.pushReplacementNamed(上下文,“/page2”);
}),
_创造者(
图标:Icons.rate_review,
文字:“写一篇评论”,
isSelected:selectedIndex==3,
onTap:(){
设置状态(){
选择指数=3;
});
Navigator.pushReplacementNamed(上下文,“/page3”);
}),
分隔符(),
],
),
),
);
}
}
小部件_createDrawerItem(
{IconData图标、字符串文本、GestureTapCallback onTap、布尔isSelected}){
回墨(
颜色:isSelected?颜色(0xffE3EAFF):颜色。透明,
孩子:ListTile(