Flutter 颤振可重排序列表返回到它';原始状态
我使列表可以重新排序,但现在它又回到了初始状态。有人能帮我吗?我的列表由使用Asynsnapshot从数据库生成的列表平铺组成。我使用的键与索引相同。似乎insert函数没有在新索引中插入注释。是因为未来的建设者正在重建吗Flutter 颤振可重排序列表返回到它';原始状态,flutter,dart,sqflite,reorderable-list,Flutter,Dart,Sqflite,Reorderable List,我使列表可以重新排序,但现在它又回到了初始状态。有人能帮我吗?我的列表由使用Asynsnapshot从数据库生成的列表平铺组成。我使用的键与索引相同。似乎insert函数没有在新索引中插入注释。是因为未来的建设者正在重建吗 body: Container( padding: EdgeInsets.all(8.0), child: ListView( children: <Widget>[ Si
body: Container(
padding: EdgeInsets.all(8.0),
child: ListView(
children: <Widget>[
SizedBox(
height: MediaQuery.of(context).size.height * 0.882,
child: FutureBuilder(
future: databaseHelper.getNoteList(),
builder: (BuildContext context, AsyncSnapshot snapshot) {
if (snapshot.data == null) {
return Text('Loading');
} else {
if (snapshot.data.length < 1) {
return Center(
child: Text('No Messages, Create New one'),
);
}
return ReorderableListView(
children: List.generate(
snapshot.data.length,
(index) {
return ListTile(
key: Key('$index'),
title: Text(
snapshot.data[index].title,
style: TextStyle(
fontWeight: FontWeight.bold,
fontSize: 20,
),
),
subtitle: Text(snapshot.data[index].note,
maxLines: 4),
trailing: InkWell(
child: Icon(Icons.add_box,
color: Colors.green),
onTap: () {
TextEditingController txt =
TextEditingController();
txt.text = snapshot.data[index].note;
print(txt);
Route route = MaterialPageRoute(
builder: (context) =>
MyHomePage(custMessage: txt));
Navigator.push(context, route);
// addNewMessageDialog(txt);
},
),
// isThreeLine: true,
onTap: () {
Route route = MaterialPageRoute(
builder: (context) => AddNote(
note: snapshot.data[index],
));
Navigator.push(context, route);
},
);
},
).toList(),
onReorder: _onReorder,
);
}
}))
],
)),
主体:容器(
填充:边缘设置。全部(8.0),
子:ListView(
儿童:[
大小盒子(
高度:MediaQuery.of(context).size.height*0.882,
孩子:未来建设者(
future:databaseHelper.getNoteList(),
生成器:(BuildContext上下文,异步快照){
如果(snapshot.data==null){
返回文本(“加载”);
}否则{
如果(snapshot.data.length<1){
返回中心(
子项:文本(“无消息,创建新消息”),
);
}
返回ReorderableListView(
子项:List.generate(
snapshot.data.length,
(索引){
返回列表块(
key:key(“$index”),
标题:正文(
snapshot.data[index].title,
样式:TextStyle(
fontWeight:fontWeight.bold,
尺寸:20,
),
),
字幕:文本(快照.数据[索引])。注意,
最大线:4),
拖尾:墨水井(
子:图标(Icons.add_框,
颜色:颜色。绿色),
onTap:(){
文本编辑控制器=
TextEditingController();
txt.text=snapshot.data[index]。注意;
打印(txt);
路线=物料管理路线(
生成器:(上下文)=>
我的主页(custMessage:txt));
推送(上下文、路线);
//addNewMessageDialog(txt);
},
),
//伊斯特里琳:是的,
onTap:(){
路线=物料管理路线(
生成器:(上下文)=>AddNote(
注意:snapshot.data[索引],
));
推送(上下文、路线);
},
);
},
).toList(),
onReorder:_onReorder,
);
}
}))
],
)),
Reoder函数
void _onReorder(int oldIndex, int newIndex) async {
var snapshot = await databaseHelper.getNoteList();
if (newIndex > snapshot.length) newIndex = snapshot.length;
if (oldIndex < newIndex) newIndex -= 1;
setState(() {
final Note item = snapshot[oldIndex];
snapshot.removeAt(oldIndex);
print(item.title);
snapshot.insert(newIndex, item);
});
}
void\u onReorder(int-oldIndex,int-newIndex)异步{
var snapshot=await databaseHelper.getNoteList();
如果(newIndex>snapshot.length)newIndex=snapshot.length;
如果(oldIndex
我试图增加未来的延迟,但没有用。
您可以复制下面的粘贴运行完整代码
您不需要在重新排序时再次调用
您可以使用noteList=snapshot.data编码>并操作注释列表
代码片段
void _onReorder(int oldIndex, int newIndex) async {
if (newIndex > noteList.length) newIndex = noteList.length;
if (oldIndex < newIndex) newIndex -= 1;
setState(() {
final Note item = noteList[oldIndex];
noteList.removeAt(oldIndex);
print(item.title);
noteList.insert(newIndex, item);
});
}
...
noteList = snapshot.data;
return ReorderableListView(
void\u onReorder(int-oldIndex,int-newIndex)异步{
如果(newIndex>noteList.length)newIndex=noteList.length;
如果(oldIndex
工作演示
完整代码
import 'package:flutter/material.dart';
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,
),
home: MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
@override
_MyHomePageState createState() => _MyHomePageState();
}
class Note {
String title;
String note;
Note({this.title, this.note});
}
class databaseHelper {
static Future<List<Note>> getNoteList() {
return Future.value([
Note(title: "1", note: "n1"),
Note(title: "2", note: "n2"),
Note(title: "3", note: "n3"),
Note(title: "4", note: "n4"),
Note(title: "5", note: "n5")
]);
}
}
class _MyHomePageState extends State<MyHomePage> {
List<Note> noteList = [];
Future<List<Note>> _future;
void _onReorder(int oldIndex, int newIndex) async {
if (newIndex > noteList.length) newIndex = noteList.length;
if (oldIndex < newIndex) newIndex -= 1;
setState(() {
final Note item = noteList[oldIndex];
noteList.removeAt(oldIndex);
print(item.title);
noteList.insert(newIndex, item);
});
}
@override
void initState() {
// TODO: implement initState
super.initState();
_future = databaseHelper.getNoteList();
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Container(
padding: EdgeInsets.all(8.0),
child: ListView(
children: <Widget>[
SizedBox(
height: MediaQuery.of(context).size.height * 0.882,
child: FutureBuilder(
future: _future,
builder: (BuildContext context, AsyncSnapshot snapshot) {
if (snapshot.data == null) {
return Text('Loading');
} else {
if (snapshot.data.length < 1) {
return Center(
child: Text('No Messages, Create New one'),
);
}
noteList = snapshot.data;
return ReorderableListView(
children: List.generate(
snapshot.data.length,
(index) {
return ListTile(
key: Key('$index'),
title: Text(
snapshot.data[index].title,
style: TextStyle(
fontWeight: FontWeight.bold,
fontSize: 20,
),
),
subtitle: Text(snapshot.data[index].note,
maxLines: 4),
trailing: InkWell(
child: Icon(Icons.add_box,
color: Colors.green),
onTap: () {
/*TextEditingController txt =
TextEditingController();
txt.text = snapshot.data[index].note;
print(txt);
Route route = MaterialPageRoute(
builder: (context) =>
MyHomePage(custMessage: txt));
Navigator.push(context, route);*/
// addNewMessageDialog(txt);
},
),
// isThreeLine: true,
onTap: () {
/*Route route = MaterialPageRoute(
builder: (context) => AddNote(
note: snapshot.data[index],
));
Navigator.push(context, route);*/
},
);
},
).toList(),
onReorder: _onReorder,
);
}
}))
],
)),
);
}
}
导入“包装:颤振/材料.省道”;
void main(){
runApp(MyApp());
}
类MyApp扩展了无状态小部件{
@凌驾
小部件构建(构建上下文){
返回材料PP(
标题:“颤振演示”,
主题:主题数据(
主样本:颜色。蓝色,
视觉密度:视觉密度。自适应平台密度,
),
主页:MyHomePage(标题:“颤振演示主页”),
);
}
}
类MyHomePage扩展StatefulWidget{
MyHomePage({Key,this.title}):超级(Key:Key);
最后的字符串标题;
@凌驾
_MyHomePageState createState()=>\u MyHomePageState();
}
课堂笔记{
字符串标题;
弦乐;
注释({this.title,this.Note});
}
类数据库助手{
静态未来getNoteList(){
返回未来值([
注(标题:“1”,注:“n1”),
注(标题:“2”,注:“n2”),
注(标题:“3”,注:“n3”),
注(标题:“4”,注:“n4”),
注(标题:“5”,注:“n5”)
]);
}
}
类_MyHomePageState扩展状态{
列表注释列表=[];
未来,未来;;
void _onReorder(int-oldIndex,int-newIndex)异步{
如果(newIndex>noteList.length)newIndex=noteList.length;