我有一個有狀態的小部件，我將一個串列傳遞給（例如 2 個專案）。洗掉專案后，小部件應自行重建。不幸的是，已洗掉的專案仍然顯示，而另一個則不顯示。當我重新輸入小部件時，會加載正確的專案。有一個類似的問題串列在洗掉專案時沒有更新， 但也許有人可以解釋我做錯了什么以及為什么提供者在這里幫助我而不是 setState？
我的代碼是：
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)),
);
},
),
);
}
}
我認為 setState 的作用與我重新輸入小部件時的作用相同，但事實并非如此。
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,
),
],
),
),
],
),
),
),
),
);
}
}
uj5u.com熱心網友回復：
如果您在 DartPad 中運行代碼的簡化版本 - 它會起作用：
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)),
);
},
),
);
}
}
這告訴我問題出在您的 PreviewUrl 上。我的猜測是 - 它是一個統計小部件，當樹重建時 - 它會將舊的 State 物件鏈接到第一項。
使用 Keys 可能會有所幫助，例如：
return PreviewUrl(
key: ObjectKey(widget.toDoList[index]),
url2: widget.toDoList[index][0],
deleteFunction: (context) => setState(() => deleteTask(index)),
);
轉載請註明出處，本文鏈接：https://www.uj5u.com/qiye/527892.html
標籤：扑颤振依赖