Deleting Item out of List, Listview.build shows wrong data - flutter

Question

I have a Stateful widget that i pass a list to (for example 2 items).
After I delete an item, the widget should rebuild itself.
Unfortunately, the deleted item is still displayed and the other one is not.
When I re-enter the widget, the correct item is loaded.
There is a similar problem List not updating on deleting item
but maybe someone can explain me what i did wrong and why provider is helping me here instead of setState?
My code is:
import 'package:firebase_database/firebase_database.dart';
import 'package:flutter/material.dart';
import 'package:trip_planner/util/dialog_box.dart';
import 'package:trip_planner/util/previewUrl.dart';
class BookingPage extends StatefulWidget {
final List toDoList;
BookingPage({
super.key,
required this.toDoList,
});
#override
State<BookingPage> createState() => _BookingPageState();
}
class _BookingPageState extends State<BookingPage> {
//text controller
final _controller = TextEditingController();
final _database = FirebaseDatabase.instance.ref();
//Liste is an example what i have in my list
List toDoList2 = [
["https://www.booking.com/Share-Rnv2Kf", true],
["https://www.booking.com/Share-3hKQ0r", true],
];
void initState(){
super.initState();
}
void deleteTask(int index){
setState(() {
widget.toDoList.removeAt(index);
});
//DatabaseReference _testRef = _database.child("Hotel:");
//_testRef.set(widget.toDoList.toString());
}
//save new Item
void saveNewItem(){
setState(() {
widget.toDoList.add([_controller.text, false]);
//DatabaseReference _testRef = _database.child("Hotel:");
//_testRef.set(widget.toDoList.toString());
_controller.clear();
});
Navigator.of(context).pop();
}
void createNewItem(){
showDialog(
context: context,
builder: (context){
return DialogBox(
controller: _controller,
onSave: saveNewItem,
onCancel: () => Navigator.of(context).pop(),
);
},
);
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Booking Seiten'),
elevation: 0,
),
floatingActionButton: FloatingActionButton(
onPressed: createNewItem,
child: Icon(Icons.add),
),
body: ListView.builder(
itemCount: widget.toDoList.length,
itemBuilder: (context, index){
return PreviewUrl(
url2: widget.toDoList[index][0],
deleteFunction: (context) => setState(() => deleteTask(index)),
);
},
),
);
}
}
i thought setState does the same thing as when i re-enter the widget, but it doesn't.
import 'package:any_link_preview/any_link_preview.dart';
import 'package:flutter/material.dart';
import 'package:flutter_slidable/flutter_slidable.dart';
import 'package:url_launcher/url_launcher.dart';
class PreviewUrl extends StatelessWidget {
final String url2;
//Function(bool?)? onChanged;
Function(BuildContext)? deleteFunction;
PreviewUrl({
super.key,
required this.url2,
required this.deleteFunction,
//required this.onChanged,
});
Future openBrowserURL({
required String url,
bool inApp = false,
}) async {
if(await canLaunch(url)){
await launch(
url,
forceSafariVC: inApp, //iOS
forceWebView: inApp, //Android
enableJavaScript: true, //Android
);
}
}
#override
Widget build(BuildContext context) {
return Padding(
padding: const EdgeInsets.all(1.0),
child: Slidable(
endActionPane: ActionPane(
motion: StretchMotion(),
children: [
SlidableAction(
onPressed: deleteFunction,
icon: Icons.delete,
backgroundColor: Colors.red.shade300,
borderRadius: BorderRadius.circular(12),
)
],
),
child: Container(
child: AnyLinkPreview.builder(
link: url2,
itemBuilder: (context, metadata, imageProvider) => Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
if (imageProvider != null)
GestureDetector(
onTap: () async {
final url = url2;
openBrowserURL(url: url, inApp: true);
},
child: Container(
constraints: BoxConstraints(
maxHeight: MediaQuery.of(context).size.width *0.25,
),
decoration: BoxDecoration(
borderRadius: BorderRadius.only(
topLeft: Radius.circular(12),
topRight: Radius.circular(12)),
image: DecorationImage(
image: imageProvider,
fit: BoxFit.cover,
),
),
),
),
Container(
width: double.infinity,
color: Theme.of(context).primaryColor.withOpacity(0.6),
padding: const EdgeInsets.symmetric(
vertical: 10, horizontal: 15),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
if (metadata.title != null)
Text(
metadata.title!,
maxLines: 1,
style:
const TextStyle(fontWeight: FontWeight.w500),
),
const SizedBox(height: 5),
if (metadata.desc != null)
Text(
metadata.desc!,
maxLines: 1,
style: Theme.of(context).textTheme.bodySmall,
),
Text(
metadata.url ?? url2,
maxLines: 1,
style: Theme.of(context).textTheme.bodySmall,
),
],
),
),
],
),
),
),
),
);
}
}

Answer 1

If you run the simplified version of your code in DartPad - it will work:
import 'package:flutter/material.dart';
const Color darkBlue = Color.fromARGB(255, 18, 32, 47);
List toDoList = [
["Button 1", true],
["Button 2", true],
];
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
theme: ThemeData.dark().copyWith(
scaffoldBackgroundColor: darkBlue,
),
debugShowCheckedModeBanner: false,
home: Scaffold(
body: Center(
child: BookingPage(toDoList: toDoList),
),
),
);
}
}
class BookingPage extends StatefulWidget {
final List toDoList;
const BookingPage({
super.key,
required this.toDoList,
});
#override
State<BookingPage> createState() => _BookingPageState();
}
class _BookingPageState extends State<BookingPage> {
//Liste is an example what i have in my list
List toDoList2 = [
["Button 1", true],
["Button 2", true],
];
#override
void initState() {
super.initState();
}
void deleteTask(int index) {
setState(() {
widget.toDoList.removeAt(index);
});
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('Booking Seiten'),
elevation: 0,
),
body: ListView.builder(
itemCount: widget.toDoList.length,
itemBuilder: (context, index) {
return ElevatedButton(
style: ElevatedButton.styleFrom(
backgroundColor: Colors.lightBlue,
padding: const EdgeInsets.all(12),
textStyle: const TextStyle(fontSize: 22),
),
child: Text(widget.toDoList[index][0]!),
onPressed: () => setState(() => deleteTask(index)),
);
},
),
);
}
}
Which tells me that the problem is your PreviewUrl. My guess is - it is a statful widget, and when the tree rebuilds - it will link the old State object to the first item.
Using Keys might help, something like:
return PreviewUrl(
key: ObjectKey(widget.toDoList[index]),
url2: widget.toDoList[index][0],
deleteFunction: (context) => setState(() => deleteTask(index)),
);