未处理的异常：类型 'List<dynamic>' 不是类型 'List<String>' 的子类型：Flutter

Question

// 我在行中有错误：_picture = snapshot.data()[PICTURE]; ，它返回未处理的异常。 “List”类型不是“List”类型的子类型 This is the image of my firebase

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//也检测到的第二个错误来自行：products.add(ProductModel.fromSnapshot(product)); 两者都抛出未处理的异常类型'List'不是类型'的子类型列表'

import 'package:cloud_firestore/cloud_firestore.dart';

class ProductModel {
static const ID = "id";
static const NAME = "name";
static const PICTURE = "picture";
static const PRICE = "price";
static const DESCRIPTION = "description";
static const CATEGORY = "category";
static const QUANTITY = "quantity";
static const BRAND = "brand";
static const PAYSTACK_ID = "paystackId";


String _id;
String _name;
List<String>  _picture;
String _description;
String _category;
String _brand;
int _quantity;
int _price;
String _paystackId;



String get id => _id;

String get name => _name;

List<String>  get picture => _picture;

String get brand => _brand;

String get category => _category;

String get description => _description;

int get quantity => _quantity;

int get price => _price;

String get paystackId => _paystackId;






ProductModel.fromSnapshot(DocumentSnapshot snapshot) {
_id = snapshot.data()[ID];
_brand = snapshot.data()[BRAND];
_description = snapshot.data()[DESCRIPTION] ?? " ";
_price = snapshot.data()[PRICE].floor();
_category = snapshot.data()[CATEGORY];
_name = snapshot.data()[NAME];
_picture = snapshot.data()[PICTURE];
_paystackId = snapshot.data()[PAYSTACK_ID] ;

}
}

Answer 1

当我将 List<dynamic> 更改为 {{1}} 时它起作用了。基本上，这可以自动扫描与“图片”集合相关联的不同图像。