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我想从 listofTaskNotApprove 类更新图像，它将文档快照的对象传递到 EditTaskNotApprove。在更新图像之前，我需要显示特定的图像，用户将从 listofTaskNotApprove 中选择特定信息。问题是如何将当前图像索引显示到新屏幕中？

ListOfTaskNotAccepted 类。

import 'package:carousel_pro/carousel_pro.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:flutter/material.dart';
import 'package:fyp/screen/RecordOfficer/EditTaskNotApprove.dart';
import 'package:fyp/shared/Loading.dart';
import 'package:google_fonts/google_fonts.dart';


class ListOfTaskNotAccepted extends StatefulWidget {
  @override
  _ListOfTaskNotAcceptedState createState() => _ListOfTaskNotAcceptedState();
}
final FirebaseAuth auth = FirebaseAuth.instance;
Stream<QuerySnapshot> getUser(BuildContext context) async* {
  final FirebaseUser rd = await auth.currentUser();
  yield* Firestore.instance.collection("Task").where('uid',isEqualTo: rd.uid).where("verified", isEqualTo: 'TidakSah').snapshots();
}
class _ListOfTaskNotAcceptedState extends State<ListOfTaskNotAccepted> {
  List<NetworkImage> _listOfImages = <NetworkImage>[];
  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: Text("Aduan Tidak Diterima"),
          backgroundColor: Colors.redAccent,
        ),
      body: Container(
      child: StreamBuilder(
          stream: getUser(context),
          builder: (context, snapshot){
            if (snapshot.hasError || !snapshot.hasData) {
              return Loading();
            } else{
              return ListView.builder(
                  itemCount: snapshot.data.documents.length,
                  itemBuilder: (BuildContext context, int index){
                   DocumentSnapshot da = snapshot.data.documents[index];
                    _listOfImages =[];
                    for(int i =0; i <da['url'].length; i++){
                      _listOfImages.add(NetworkImage(da['url'][i]));
                    }
                    return Card(
                        child:ListTile(
                          title: Container(
                            alignment: Alignment.centerLeft,
                            child: Column(
                              children: <Widget>[
                                SizedBox(height: 5.0),
                                Container(alignment: Alignment.centerLeft,
                                  child: Row(
                                    children: [
                                      Text("Sumber Aduan: ", style: GoogleFonts.asap(fontWeight: FontWeight.bold)),
                                      Text(da['sumberAduan'], style: GoogleFonts.asap(fontWeight: FontWeight.bold)),
                                    ],
                                  ),
                                ),
                                SizedBox(height: 5.0),
                                Container(alignment: Alignment.centerLeft,
                                  child: Row(
                                    children: [
                                      Text("Nombor Aduan: ", style: GoogleFonts.lato(fontWeight: FontWeight.bold)),
                                      Text(da['noAduan'], style: GoogleFonts.lato(fontWeight: FontWeight.bold)),
                                    ],
                                  ),
                                ),
                                SizedBox(height: 5.0),
                                Container(alignment: Alignment.centerLeft,
                                  child: Row(
                                    children: [
                                      Text("Lokasi: ", style: GoogleFonts.lato(fontWeight: FontWeight.bold)),
                                      Text(da['kawasan'] + " " + da['naJalan'], style: GoogleFonts.lato(fontWeight: FontWeight.bold)),
                                    ],
                                  ),
                                ),
                                SizedBox(height: 5.0),
                                Container(alignment: Alignment.centerLeft,
                                  child: Row(
                                    children: [
                                      Text("Kategori: ", style: GoogleFonts.arimo(fontWeight: FontWeight.w500)),
                                      Text(da['kategori'], style: GoogleFonts.arimo(fontWeight: FontWeight.w500)),
                                    ],
                                  ),
                                ),
                                Column(
                                  children: [
                                    Container(
                                      margin: EdgeInsets.all(10.0),
                                      height: 200,
                                      decoration: BoxDecoration(
                                          color: Colors.white
                                      ),
                                      width: MediaQuery.of(context).size.width,
                                      child: Carousel(
                                        boxFit: BoxFit.cover,
                                        images: _listOfImages,
                                        autoplay: false,
                                        indicatorBgPadding: 5.0,
                                        dotPosition: DotPosition.bottomCenter,
                                        animationCurve: Curves.fastLinearToSlowEaseIn,
                                        animationDuration: Duration(milliseconds: 2000),
                                      ),
                                    )
                                  ],
                                )
                              ],
                            ),
                          ),
                          subtitle: Container(
                          child: Column(
                            children: [
                              SizedBox(height: 5.0),
                              Container(alignment: Alignment.centerLeft,
                                child: Row(
                                  children: [
                                    Text("Catatan: ", style: GoogleFonts.arimo(fontWeight: FontWeight.w500)),
                                    Text(da['comments'], style: GoogleFonts.arimo(fontWeight: FontWeight.w500)),
                                  ],
                                ),
                              ),
                            ],
                          ),
                        ),
                          onTap: () {Navigator.push(context, MaterialPageRoute(builder: (context) => EditTask(da:da)));}
                        )
                    );
                  });
               }
          }),
       )
    );
  }
}

这是 EditTask 类，我需要显示用户选择的图像的当前索引。

import 'package:carousel_pro/carousel_pro.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:flutter/material.dart';



class EditTask extends StatefulWidget {
 final DocumentSnapshot da;

  const EditTask({Key key, this.da}) : super(key: key);

  @override
  _EditTaskState createState() => _EditTaskState(da);
}

class _EditTaskState extends State<EditTask> {
  DocumentSnapshot da;
  _EditTaskState(DocumentSnapshot da){
    this.da = da;
  }
 TextEditingController _noAduan;
 TextEditingController _sumberAduan;
 TextEditingController _kategori;
  DateTime myDateTime = DateTime.now();
 @override
 void initState(){
   super.initState();
   _noAduan = TextEditingController(text: widget.da.data['noAduan']);
   _sumberAduan =TextEditingController(text: widget.da.data['sumberAduan']);
   _kategori = TextEditingController(text: widget.da.data['kategori']);
   myDateTime = (da.data['date']).toDate();
  _listOfImages = NetworkImage(da.data['url']) as List<NetworkImage>; // this line show the error 

}

  List <String> sumber = <String> ['Sistem Aduan MBPJ', 'Sistem Aduan Waze', 'Sistem Aduan Utiliti'];
  List <String> kate = <String> ['Segera', 'Pembaikan Biasa'];
  String kategori;
  String sumberAduan;
  List <NetworkImage> _listOfImages = <NetworkImage>[];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: Text("Kemaskini Aduan"),
          backgroundColor: Colors.redAccent,
        ),
    body: Container(
      padding: const EdgeInsets.all(16.0),
      child: Center(
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.end,
            children: [
              SizedBox(height: 10.0),
              TextFormField(
                decoration:InputDecoration(
                    hintText: myDateTime.toString(),
                    border: OutlineInputBorder(
                        borderRadius: BorderRadius.circular(5))),
                onChanged: (value){
                  setState(() {
                    myDateTime = value as DateTime;
                    print(myDateTime);
                  });
                },
              ),
              SizedBox(height: 10.0),
              TextFormField(
                decoration:InputDecoration(
                  border: OutlineInputBorder(
                  borderRadius: BorderRadius.circular(5))),
                controller: _noAduan,
              ),
              SizedBox(height: 10.0),
              DropdownButtonFormField(
                hint:Text(widget.da.data['sumberAduan']),
                decoration: InputDecoration(
                    prefixIcon: Icon(Icons.perm_contact_calendar),
                    border: OutlineInputBorder(borderRadius: BorderRadius.circular(5))),
                isExpanded: true,
                value: sumberAduan,
                onChanged: (newValue) {
                  setState(() {
                    sumberAduan = newValue;
                    _sumberAduan.text = sumberAduan;
                  });
                },
                items: sumber.map((sum){
                  return DropdownMenuItem(
                    value: sum,
                    child: new Text(sum),
                  );
                }).toList(),
              ),
              SizedBox(height: 10.0),
              DropdownButtonFormField(
                hint:Text(widget.da.data['kategori']),
                decoration: InputDecoration(
                    prefixIcon: Icon(Icons.perm_contact_calendar),
                    border: OutlineInputBorder(borderRadius: BorderRadius.circular(5))),
                isExpanded: true,
                value: kategori,
                onChanged: (newValue) {
                  setState(() {
                    kategori = newValue;
                    _kategori.text = kategori;
                  });
                },
                items: kate.map((ka){
                  return DropdownMenuItem(
                    value: ka,
                    child: new Text(ka),
                  );
                }).toList(),
              ),
              Container(
                margin: EdgeInsets.all(10.0),
                height: 200,
                decoration: BoxDecoration(
                    color: Colors.white
                ),
                width: MediaQuery.of(context).size.width,
                child: Carousel(
                  boxFit: BoxFit.cover,
                  autoplay: false,
                  //images: _listOfImages,
                  indicatorBgPadding: 5.0,
                  dotPosition: DotPosition.bottomCenter,
                  animationCurve: Curves.fastLinearToSlowEaseIn,
                  animationDuration: Duration(milliseconds: 2000),
                ),
              )
            ],
          ),
      ),
    )
    );
  }
}

更新图像需要显示的 图像 当用户想要从 ListOfTaskNotApprove 更新信息时，这就是我想在 EditTask 类中显示图像的方式

该错误表明“类型'List'不是'String'类型的子类型”有人可以帮助我吗？因为我尝试了很多方法来解决这个问题，但它对我不起作用。

4

2 回答 2

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问题是您从 Firebase 存储中获取了一个 URL 列表，这些 URL 是字符串，但是您将此字符串添加到网络图像类型的列表中，这是错误的。由于字符串列表无法转换为网络映像列表。

有两种方法可以解决这个问题-

  1. 将列表类型更改为列表，然后在显示此图像的任何位置使用列表数据作为网络图像的参数。

     List<String> urls=new List();
 //suppose list is not empty
 ....
 return NetworkImage(urls[i]);
 ....

  2. 在将 url 添加到列表中时，添加一个网络图像对象并在显示图像时直接使用列表项。

     List<NetworkImage> list=new List();
 list.add(NetworkImage('some url'));
 ....
 return list[i];
 ....
于 2020-12-13T04:07:06.000 回答
0

你说：

_listOfImages = NetworkImage(da.data['url']) as List<NetworkImage>; // this line show the error

是的，您不能将 aNetworkImage转换为 a List<NetworkImage>。你可能的意思是：

_listOfImages = [ NetworkImage(da.data['url']) ] as List<NetworkImage>;
于 2020-12-13T17:35:52.623 回答