颤振 - Dart 解析 json 数据数组返回类型"列表<dynamic>"不是类型"列表"的子类型<BusinessTest>

Question

我试图使用自定义模型解析json文件，我总是得到错误type 'List<dynamic>' is not a subtype of type 'List<BusinessTest>'，我不知道如何修复我的代码。此外，它是一个好主意，总是使用空类型的变量，当你解析json文件?

这是我的数据的Json示例:

{
"businesses": [{
"id": "1",
"alias": "123",
"name": "aaa",
"image_url": "xxx.jpg",
"is_closed": false,
"url": ".com",
"review_count": 26,
"rating": 5.0
},
{
"id": "2",
"alias": "123",
"name": "aaa",
"image_url": "xxx.jpg",
"is_closed": false,
"url": ".com",
"review_count": 26,
"rating": 5.0
}
]
}

这是我为了解析Json所做的模型代码:

class BusinessSearch {
final List<BusinessTest> businesses;
final int total;
BusinessSearch(this.businesses, this.total);
BusinessSearch.fromJson(Map<String, dynamic> json)
: businesses = json['businesses'],
total = json['total'];
}
class BusinessTest {
final String? name;
final String? imageUrl;
final bool? isClosed;
final String? url;
final int? reviewCount;
BusinessTest(
this.name, this.imageUrl, this.isClosed, this.url, this.reviewCount);
BusinessTest.fromJson(Map<String, dynamic> json)
: name = json['name'],
imageUrl = json['image_url'],
isClosed = json['is_closed'],
url = json['url'],
reviewCount = json['review_count'];
}

这就是我试图解析它的方式:

void getData() async {
try {
String url =  'url';
NetworkHelp network = NetworkHelp(url: url);
var data = await network.getData();
Map<String, dynamic> businessMap = await jsonDecode(data);
var business = BusinessSearch.fromJson(businessMap);
} catch (e) {
print(e);
}
}

Answer 1

您必须像这样更新您的BusinessSearch模型。

class BusinessSearch {
BusinessSearch({
this.businesses,
this.total,
});
List<Business> businesses = [];
int total;
factory BusinessSearch.fromJson(Map<String, dynamic> json) => BusinessSearch(
businesses: List<Business>.from(json["businesses"].map((x) => Business.fromJson(x))),
total: json['total']
);
Map<String, dynamic> toJson() => {
"businesses": List<dynamic>.from(businesses.map((x) => x.toJson())),
"total": total,
};
}
class Business {
Business({
this.id,
this.alias,
this.name,
this.imageUrl,
this.isClosed,
this.url,
this.reviewCount,
this.rating,
});
String id;
String alias;
String name;
String imageUrl;
bool isClosed;
String url;
int reviewCount;
int rating;
factory Business.fromJson(Map<String, dynamic> json) => Business(
id: json["id"],
alias: json["alias"],
name: json["name"],
imageUrl: json["image_url"],
isClosed: json["is_closed"],
url: json["url"],
reviewCount: json["review_count"],
rating: json["rating"],
);
Map<String, dynamic> toJson() => {
"id": id,
"alias": alias,
"name": name,
"image_url": imageUrl,
"is_closed": isClosed,
"url": url,
"review_count": reviewCount,
"rating": rating,
};
}