我正在ListView中搜索，并且在过滤后的列表中获得搜索结果，但是当我在listview中选择搜索项并清除原始列表中的搜索框时，将取消选择我选择的项。我的原始列表是代码中的“ rest”列表，而过滤后的列表是代码中使用的“ filteredList”。当我不熟悉时，请帮助我解决问题。
import 'dart:convert';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:http/http.dart' as http;
import 'package:shared_preferences/shared_preferences.dart';
String stringValue="default";
String Currentdate;
const lightGrey = Color(0xff858585);
const darkGrey = Color(0xff404042);
const orange = Color(0xffff8500);
const blue = Color(0xff2f5597);
const skyblue=Color(0xffF1F5F9);
const darkblue=Color(0xffD4E7F9);
class AttendencePage2 extends StatefulWidget {
final String centernametext,batchname,date,centerid,batchid,accesstoken;
AttendencePage2(this.centernametext,this.batchname,this.date,this.centerid,this.batchid,this.accesstoken);
@override
State<StatefulWidget> createState() {
// TODO: implement createState
return _AttendencePage2();
}
}
class _AttendencePage2 extends State<AttendencePage2> {
int i;
String str_accesstoken;
List rest;
List<Autogenerated> list= List<Autogenerated>();
List filteredlist;
TextEditingController controller = new TextEditingController();
bool isSelected = false;
List<int> indexList = new List();
bool longPressFlag = false;
void longPress() {
setState(() {
if (indexList.isEmpty) {
longPressFlag = false;
} else {
longPressFlag = true;
}
});
}
var mycolor=Colors.white;
bool checkVal = false;
bool checkVal2=false;
@override
void initState() {
super.initState();
getStringValuesSF();
StudentListRequest();
}
@override
Widget build(BuildContext context) {
// for (var i = 0; i < 50; i++) {
// indexList.add(Element(isSelected: false));
// }
SystemChrome.setSystemUIOverlayStyle(SystemUiOverlayStyle(
systemNavigationBarColor: Colors.white, // navigation bar color
statusBarColor: Colors.black, // status bar color
));
return MaterialApp(
home: Scaffold(
appBar: AppBar(
centerTitle: true,
backgroundColor: orange,
title: Text('ATTENDENCE'),
),body:
Stack(
children: <Widget>[
Container(
color: Colors.white,
),
Container(
color: skyblue,
width: double.infinity,
height: 65,
padding: EdgeInsets.only(right: 20,left: 20,top: 10,bottom: 10),
child:Row(
children: <Widget>[
Container(
child:Column(children: <Widget>[
Text("Center Name",style: TextStyle(color: lightGrey,fontSize: 17)),
Container(
margin: EdgeInsets.only(top:5),
child:Text(widget.centernametext.toUpperCase(),style: TextStyle(color: Colors.black,fontSize: 13)),
),
],)
//child:
),
Spacer(),
Container(
child:Column(children: <Widget>[
Text("Batch",style: TextStyle(color: lightGrey,fontSize: 17),textAlign: TextAlign.left,),
Container(
margin: EdgeInsets.only(top:5),
child:Text(widget.batchname,style: TextStyle(color: Colors.black,fontSize: 13)),),
],)
),
Spacer(),
Container(
child:Column(children: <Widget>[
Text("Date",style: TextStyle(color: lightGrey,fontSize: 17)),
Container(
margin: EdgeInsets.only(top:5),
child:Text(widget.date,style: TextStyle(color: Colors.black,fontSize: 13)),
),
],)
),
Container(
margin: EdgeInsets.only(left: 10),
child: Image.asset('assets/grey_edit.png',width: 20,height: 25),
),
],
)
),
_searchBar(),
Container(
color: skyblue,
width: double.infinity,
height: 50,
margin: EdgeInsets.only(top:155,left: 10,right: 10),
padding: EdgeInsets.only(right: 20,left: 0,top: 10,bottom: 10),
child:Row(
children: <Widget>[
Container(
child: Checkbox(
value: checkVal,
onChanged: (bool value) {
setState(() {
checkVal = value;
if(checkVal==true){
isSelected=true;
}else{
isSelected=false;
}
});
} ),
),
Container(margin: EdgeInsets.only(top:5),
child:Column(children: <Widget>[
Text("Name",style: TextStyle(color: lightGrey,fontSize: 15)),
],)
),
Spacer(),
Container(margin: EdgeInsets.only(top:5),
child:Column(children: <Widget>[
Text(" ",style: TextStyle(color: lightGrey,fontSize: 15),textAlign: TextAlign.left,),
],)
),
Spacer(),
Container(margin: EdgeInsets.only(top:5),
child:Column(children: <Widget>[
Text("Level ",style: TextStyle(color: lightGrey,fontSize: 15)),
],)
),
Spacer(),
Container(margin: EdgeInsets.only(top:5),
child:Column(children: <Widget>[
Text("No. of class",style: TextStyle(color: lightGrey,fontSize: 15)),
],)
),
Spacer(),
Container(margin: EdgeInsets.only(top:5),
child:Column(children: <Widget>[
Text("Attend",style: TextStyle(color: lightGrey,fontSize: 15)),
],)
),
],
)
),
Container(
margin: EdgeInsets.only(top:205,left: 10,right: 10),
decoration: BoxDecoration(
border: Border.all(color: darkblue)
),
child: ListView.builder(
//addAutomaticKeepAlives: true,
itemCount: filteredlist==null?0:filteredlist.length,
// padding: const EdgeInsets.all(2.0),
itemBuilder: (context, index) {
return new CustomWidget(
selected:isSelected,
rest:filteredlist,
index: index,
longPressEnabled: longPressFlag,
callback: () {
longPress();
},
);
})
)])));
}
_searchBar() {
return Container(
child:Row(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Container(
width: 350,
height: 40,
margin: EdgeInsets.only(left:20,top:90),
child:TextField(
decoration: InputDecoration(
contentPadding: EdgeInsets.fromLTRB(20.0, 15.0, 20.0, 15.0),
prefixIcon: new Padding(
padding: const EdgeInsets.only( top: 13, left: 0, right: 5, bottom: 13),
child: new SizedBox(
height: 2,
child: Image.asset('assets/search.png'),
),
),
labelText: "Search by name",
labelStyle: TextStyle(
color: lightGrey,
fontSize: 15
),
border: OutlineInputBorder( borderSide: BorderSide(color: lightGrey, width: 0.5),
borderRadius: BorderRadius.circular(5.0)),
focusedBorder: OutlineInputBorder(
borderSide: BorderSide(color: orange, width: 0.5),
borderRadius: BorderRadius.circular(5.0)
)),
controller: controller,
onChanged: (string){setState(() {
filteredlist=rest.where((f){
var dataName=f['student']['name'].toString().toLowerCase();
var dataName2=f['course']['level_no'].toString().toLowerCase();
return dataName.contains(string)||dataName2.contains(string);
}).toList();
}
);
},
)
),
],
)
);
}
Future<List<Autogenerated>> StudentListRequest() async {
String as=widget.accesstoken.toString();
var url = 'http://demo.neurapses.com:3032/students?center=5ca5ba30e0adb9c1839aa0d2&batch=5ca5c81597f8a03368df072c';
var response = await http.get(url,
headers: {
'Content-Type': 'application/json',
'Authorization': 'Bearer $as'
},
);
final int statusCode = response.statusCode;
if (statusCode < 200 || statusCode > 400 || json == null) {
throw new Exception("Error while fetching data");
} else {
setState(() {
var data = json.decode(response.body);
rest = data['docs'];
for(var rest in rest)
{
list.add(Autogenerated.fromJson(rest));
}
filteredlist=rest;
});
return list;
}
}
getStringValuesSF() async {
SharedPreferences prefs = await SharedPreferences.getInstance();
str_accesstoken = prefs.getString('accesstoken');
}
}
class Autogenerated {
List<Docs> docs;
Autogenerated({this.docs});
Autogenerated.fromJson(Map<String, dynamic> json) {
if (json['docs'] != null) {
docs = new List<Docs>();
json['docs'].forEach((v) {
docs.add(new Docs.fromJson(v));
});
}
}
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = new Map<String, dynamic>();
if (this.docs != null) {
data['docs'] = this.docs.map((v) => v.toJson()).toList();
}
return data;
}
}
class Docs {
Student student;
Docs(
{
this.student,
});
Docs.fromJson(Map<String, dynamic> json) {
student =
json['student'] != null ? new Student.fromJson(json['student']) : null;
}
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = new Map<String, dynamic>();
if (this.student != null) {
data['student'] = this.student.toJson();
}
return data;
}
}
class Student {
String name;
Student(
{
this.name,
});
Student.fromJson(Map<String, dynamic> json) {
name = json['name'];
}
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = new Map<String, dynamic>();
data['name'] = this.name;
return data;
}
}
class CustomWidget extends StatefulWidget {
final int index;
final bool longPressEnabled;
final VoidCallback callback;
final List rest;
bool selected;
CustomWidget({Key key, this.selected, this.rest, this.index, this.longPressEnabled, this.callback}) : super(key: key);
@override
_CustomWidgetState createState() => new _CustomWidgetState();
}
class _CustomWidgetState extends State<CustomWidget> {
final skyblue=Color(0xffF1F5F9);
@override
Widget build(BuildContext context) {
return new GestureDetector(
onLongPress: () {
widget.callback();
},
onTap: () {
if (widget.longPressEnabled) {
widget.callback();
}
},
child:Container(
margin: new EdgeInsets.only(top:5.0),
color: widget.selected ? Colors.grey[300]:Colors.white,
child:Row(children: <Widget>[
Flexible(
fit:FlexFit.loose,
child: ListTile(
contentPadding: EdgeInsets.only(left: 0.0, right: 0.0),
title:
Container(
child:Column(children: <Widget>[
Row(
children: <Widget>[
Container(
child: Checkbox(
onChanged: (val) {
setState(() {
widget.selected = !widget.selected;
});
},
value: widget.selected,
),
),
Container(
child:Container(width:80,child:Text(widget.rest[widget.index]['student']['name'], style: TextStyle(color: Colors
.black, fontSize: 13),
)),
),
Spacer(),
Container(
child: Text(widget.rest[widget.index]['course']['level_no'], style: TextStyle(color: Colors
.black, fontSize: 13),)
),
Spacer(),
Container(
child: Text(
"", style: TextStyle(color: Colors.black,
fontSize: 13),)
),
Spacer(),
Container(
child: Text("", style: TextStyle(color: Colors
.black, fontSize: 13),)
),
],
),
Container(
color: darkblue,
height: 0.7,
width: double.infinity,
),
]),
// onLongPress: toggleSelection,
))
)],),
));
}
}
用于显示搜索栏和具有1000个项目的ListView的UI代码
import 'package:flutter/material.dart';
void main() => runApp(new MyApp());
class MyApp extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return new MaterialApp(
title: 'Flutter Demo',
theme: new ThemeData(
primarySwatch: Colors.blue,
),
home: new MyHomePage(title: 'ListView with Search'),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
@override
_MyHomePageState createState() => new _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
TextEditingController editingController = TextEditingController();
final duplicateItems = List<String>.generate(10000, (i) => "Item $i");
var items = List<String>();
@override
void initState() {
items.addAll(duplicateItems);
super.initState();
}
@override
Widget build(BuildContext context) {
return new Scaffold(
appBar: new AppBar(
title: new Text(widget.title),
),
body: Container(
child: Column(
children: <Widget>[
Padding(
padding: const EdgeInsets.all(8.0),
child: TextField(
onChanged: (value) {
},
controller: editingController,
decoration: InputDecoration(
labelText: "Search",
hintText: "Search",
prefixIcon: Icon(Icons.search),
border: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(25.0)))),
),
),
Expanded(
child: ListView.builder(
shrinkWrap: true,
itemCount: items.length,
itemBuilder: (context, index) {
return ListTile(
title: Text('${items[index]}'),
);
},
),
),
],
),
),
);
}
}