向左滑动时，不会删除列表项

Question

我是个新手。我有一个任务，其中有一个项目要删除左侧创建的注释。用滑动删除列表项目时，它会被删除，直到我进行热重新启动。当我进行热重启时，项目会重新出现。也许我的代码中有个错误。请帮帮我。

import 'dart:convert';
import 'dart:collection';
import 'package:flutter/material.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter/rendering.dart';
import 'package:shared_preferences/shared_preferences.dart';


class Home extends StatefulWidget {
const Home ({key}): super(key: key);

@override
State<Home> createState() => _HomeState();
}
class _HomeState extends State<Home> {

final myController = TextEditingController();
bool submit = false;

Color mainColor = Color(0xFFEEEFF5);
Color secColor = Color(0xFF3A3A3A);
Color tdBlue = Color(0xFF5F52EE);


String temp = "";
List<String> todoList = [];
String index = "";

@override
void initState() {

super.initState();

myController.addListener(() {
setState(() {
submit = myController.text.isNotEmpty;
});
});

omLoadData();
}

submitData() async {
setState(() {
todoList.add(temp);
clearText();
});
SharedPreferences prefs = await SharedPreferences.getInstance();
await prefs.setStringList('todo_list', todoList);
}

omLoadData() async {
SharedPreferences prefs = await SharedPreferences.getInstance();
final data = prefs.getStringList("todo_list");
todoList.addAll(data!);
}

@override
void dispose() {
// Clean up the controller when the widget is disposed.
myController.dispose();
super.dispose();
}

void clearText() {
myController.clear();
}


@override
Widget build(BuildContext context){
return Scaffold(
backgroundColor: mainColor,
appBar: AppBar(
elevation: 0.0,
backgroundColor: secColor,
title: Text ('ToDo - List', style: TextStyle(fontSize: 26.5, fontWeight: FontWeight.bold, fontStyle: FontStyle.italic),),
),
body: Column(
children: [
Container(

margin: EdgeInsets.only(
top: 15.0,
left: 13.0,
right: 8.0,
),
child: Row(
children: [
Expanded(
child: TextField(
onChanged: (String value) {
temp = value;
},

controller: myController,
decoration:
InputDecoration(
prefixIcon: Icon(Icons.notes, color: Colors.orangeAccent,),
labelText: 'Замітка',
hintText: 'Введіть замітку',
filled: true,
fillColor: Colors.white,
border: OutlineInputBorder(),
contentPadding: EdgeInsets.all(10.0),
enabledBorder: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(30.0),),

),
),
),
),
SizedBox(
width: 10.0,
),
ElevatedButton(
style: ElevatedButton.styleFrom(backgroundColor: tdBlue),

onPressed:
submit ? () => submitData() : null,
child:
Text('+', style: TextStyle(fontSize: 35),),
),
], // Закривається 2-ий чілдрен
), //Row 1-ий
),

Expanded(
child: Padding(
padding: EdgeInsets.only(
top: 5.0,
),
child: ListView.builder(

itemCount: todoList.length,
itemBuilder: (BuildContext context, int index){
final item  =  todoList[index];
return Dismissible(
direction: DismissDirection.endToStart,
background: const Card(color: Colors.red,
child: Icon(Icons.delete_sweep,size: 30, color: Colors.white,)
),
key: Key(todoList[index]),
onDismissed: (direction){
setState(() {
todoList.removeAt(index);
});
},
child: Card(
margin: EdgeInsets.only(
top: 8.5,
left: 25.0,
right: 25.0,
),
shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(25.0)),
elevation: 0.0,
child:
ListTile(
title: Text(todoList[index],
),),
),

);
},
),
)

),

],
),
);
}
}

尝试了不同的删除选项。观看视频和阅读文章。所考虑的方案都不起作用。也许我的代码中有个错误。

Answer 1

删除SharedPreferences上的项目时更新列表

onDismissed: (direction) async {
setState(() {
todoList.removeAt(index);
});
SharedPreferences prefs = await SharedPreferences.getInstance();
await prefs.setStringList('todo_list', todoList);
},