Question

我正在尝试从Firebase访问特定文档的数据我使用外部索引来指定哪个文档。我正在使用具有字符串和动态列表的aniaml模型我的firebase文档包含字符串和字符串列表 DatabaseService.dart

    import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:hkScan/models/animal.dart';

class DatabaseService {
  DatabaseService({this.index});
  final index;
  final CollectionReference animalsCollection =
      Firestore.instance.collection('Animals');

  Animal _animalFromSnapshot(QuerySnapshot snapshot) {
    try {
     return Animal(
      type: snapshot.documents[index].data['type"'] ?? '',
      feeding: snapshot.documents[index].data['feeding'] ?? '',
      slaughter: snapshot.documents[index].data['slaughter'] ?? '',
      breed: snapshot.documents[index].data['breed'] ?? '',
      cuts: snapshot.documents[index].data['cuts'] ?? '',
      grading: snapshot.documents[index].data['rating'] ?? '',
      image: snapshot.documents[index].data['image'] ?? '',
    );} catch(e){print(e.toString());return null;}
  }

  Stream<Animal> get animals {
    return animalsCollection.snapshots().map<Animal>(_animalFromSnapshot);
  }
}

动物模型：

class Animal {
  final String type;
  final String feeding;
  final List<dynamic> slaughter;
  final List<dynamic> breed;
  final List<dynamic> grading;
  final List<dynamic> cuts;
  final List<dynamic> image;
  Animal(
      {this.type,
      this.feeding,
      this.slaughter,
      this.breed,
      this.grading,
      this.cuts,
      this.image});
}

这就是我使用StreamProvider将流从Firebase传递到我的应用的方式

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:hkScan/models/animal.dart';
import 'package:hkScan/services/database.dart';
import 'package:hkScan/widgets/animalsGrid.dart';
import 'package:hkScan/widgets/productCard.dart';
import 'package:provider/provider.dart';

import 'models/style.dart';

class Body extends StatefulWidget {
  @override
  _BodyState createState() => _BodyState();
}

class _BodyState extends State<Body> {
  int isSelected = 0;
  int dindex = 0;
  @override
  Widget build(BuildContext context) {
    return StreamProvider<Animal>.value(
      value: DatabaseService(index: dindex).animals,

          child: Container(
            color: Color(0xFF161D36),
            child: Stack(
              children: [
.
.
.
.
.
                Positioned(
                    left: 21,
                    top: 355,
                    height: 290,
                    width: 260,
                    child: ListView.builder(
                        itemCount: 2,
                        itemBuilder: (context, index) {
                          final animal = Provider.of<Animal>(context);
                          return animal==null? Container():ProductCard(animal: animal,index: index,);
                        })),
.
.
.
.
.

产品卡：

import 'dart:ui';

import 'package:flutter/material.dart';
import 'package:hkScan/models/animal.dart';

import 'package:hkScan/models/style.dart';

class ProductCard extends StatelessWidget {
  final Animal animal;
  final index;
  ProductCard({this.animal, this.index});
  @override
  Widget build(BuildContext context) {
    return ClipPath(
      clipper: RoundedDiagonalPathClipper(),
      child: Stack(children: [
        Container(
          decoration: BoxDecoration(
            color: Colors.red,
            borderRadius: BorderRadius.circular(25),
            
          ),
        ),
        Positioned(
          child: ClipRRect(
            borderRadius: BorderRadius.only(
                bottomLeft: Radius.circular(25),
                bottomRight: Radius.circular(25)),
            child: BackdropFilter(
              filter: ImageFilter.blur(sigmaX: 25.0, sigmaY: 25.0),
              child: Container(
                width: 260.0,
                height: 71.0,
                decoration: BoxDecoration(
                  color: Colors.grey[900].withOpacity(0.2),
                  boxShadow: [
                    BoxShadow(
                      color: Colors.black38,
                      blurRadius:
                          15.0, // has the effect of softening the shadow
                      spreadRadius:
                          10.0, // has the effect of extending the shadow
                      offset: Offset(
                        -13.0, // horizontal, move right 10
                        15.0, // vertical, move down 10
                      ),
                    )
                  ],
                ),
              ),
            ),
          ),
          bottom: 0,
        ),
        Positioned(
            left: 20,
            bottom: 15,
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(animal.type,
                    style: myStyle((20), FontWeight.w400, Color(0xFFD1E2F4))),
                Text(animal.grading[index],
                    style: myStyle((15), FontWeight.w400, Color(0xFFD1E2F4)))
              ],
            )),
      ]),
    );
  }
}

FireBase： Firebase Console 但是我一直收到此错误：

I/flutter (11723): type 'String' is not a subtype of type 'List<dynamic>'

我该如何解决？谢谢

Flutter / Firebase类型“ String”不是类型“ List <dynamic>”的子类型

0 个答案: