新：类型“_InternalLinkedHashMap<String, dynamic>”不是“DocumentSnapshot”类型的子类型

Posted 2023-02-23

【中文标题】新：类型“_InternalLinkedHashMap<String, dynamic>”不是“DocumentSnapshot”类型的子类型

【英文标题】：New: type '_InternalLinkedHashMap<String, dynamic>' is not a subtype of type 'DocumentSnapshot'

【发布时间】：2020-03-26 13:49:40

【问题描述】：

对不起，我现在正在编程，但我正在学习，请帮助我。我被困在这个问题上。这是我的第一个应用程序之一，几乎完成了，所以需要 likeke 的帮助才能完成。

我收到此错误：类型“_InternalLinkedHashMap”不是类型“DocumentSnapshot”的子类型

代码如下所示：

    import 'package:flutter/material.dart';
    import 'package:brew_app/services/auth.dart';
    import 'package:cloud_firestore/cloud_firestore.dart';

    class Home extends StatelessWidget 

    final AuthService _auth = AuthService();
    @override
    Widget build(BuildContext context) 
     return Scaffold(
      backgroundColor : Colors.grey[50],
      appBar: AppBar(
        title: Text('Brew Crew'),
        backgroundColor: Colors.orange[400],
        elevation: 0.0,
        actions: <Widget>[
          FlatButton.icon(
            icon: Icon(Icons.person),
            label: Text('Logout'),
            onPressed:() async 
              await _auth.signOut();

           ,

         )
       ],
     ),
     body: ListPage(),
   );
 

  class ListPage extends StatefulWidget 



    @override
    _ListPageState createState() => _ListPageState();
  

  class _ListPageState extends State<ListPage> 

 Future getPosts() async 
   var firestore = Firestore.instance;

QuerySnapshot qn = await firestore.collection("posts").getDocuments();

return qn.documents;


  

  navigateToDetails(DocumentSnapshot post)
    Navigator.push(context, MaterialPageRoute(builder: (context) => DetailPage(post: post,)));
  

 @override
  Widget build(BuildContext context) 
    return Container(
     child: FutureBuilder(
       future: getPosts(),
         builder: (_, snapshot)
        if(snapshot.connectionState == ConnectionState.waiting) 
          return Center(
            child: Text("Loading..."),
          );
         else 
          return ListView.builder(
              itemCount: snapshot.data.length,
              itemBuilder: (_, index)

                return ListTile(
                  title: Text(snapshot.data[index].data["title"]),
                  onTap: () => navigateToDetails(snapshot.data[index].data),
                );

          );


    

  ),
);

class DetailPage extends StatefulWidget 


  final DocumentSnapshot post;

  DetailPage(this.post);
  @override
  _DetailPageState createState() => _DetailPageState();


class _DetailPageState extends State<DetailPage> 
  @override
  Widget build(BuildContext context) 
    return Container(
      child: Card(
        child: ListTile(
          title: Text(widget.post.data["title"]),
          subtitle: Text(widget.post.data["content"]),
        )
      )
    );
  

【参考方案1】：

使用此代码：

snapshot.data[index].data // is of type Map<String,Dynamic>     
snapshot.data[index] // is the DocumentSnapshot

【讨论】：

欢迎接受答案或投票赞成：D