json解析服务器List数据问题

服务器端返回数据:

[{"title":"空间","tags":["矩形房间","干湿分离","多开间进深"]},{"title":"手法","tags":["砖墙","铝膜","木模"]},{"title":"特征","tags":["落地窗","飘窗","普通窗","降板"]},{"title":"建筑","tags":["高层","别墅","复式","联排"]}]

自定义Bean对象如下:

class TagData {
  String title = "";
  List<String> tags = [];

  TagData();

  TagData.fromJson(Map<String, dynamic> map) {
    this.title = map["title"];
    this.tags = (map["tags"] as List).map((e) => e.toString()).toList();
  }

  Map<String, dynamic> toJson() => <String, dynamic>{"title": this.title, "tags": this.tags};
}

为方便使用自定义字符串接收服务器端返回的数据(十几种可以直接转换,可能不需要)

String jsonData=[{"title":"空间","tags":["矩形房间","干湿分离","多开间进深"]},{"title":"手法","tags":["砖墙","铝膜","木模"]},{"title":"特征","tags":["落地窗","飘窗","普通窗","降板"]},{"title":"建筑","tags":["高层","别墅","复式","联排"]}];

方法一、推荐解析如下:

List<dynamic> tagDataList1 = jsonDecode(jsonData);//不建议直接使用List<TagData>接收,要先过渡一下
List<TagData> tagDataList2 = tagDataList1.map((e) => TagData.fromJson(e)).toList();
//检验结果
tagDataList2.forEach((tagData) {
  print("=======tagData标题:::${tagData.title}==============");
  List.generate(tagData.tags.length, (index) => print("=======tagData[$index]:::${tagData.tags[index]}=============="));
});

结果如下:

到此处理结束.

方法二、我开始在解析的时候没有想到要过渡一下,直接使用List<TagData> 接收的

List<TagData> tagDataList1 = jsonDecode(jsonData);
tagDataList1.forEach((tagData) {
  print("=======tagData标题:::${
  tagData["title"]}==============");
  List.generate(tagData["tags"].length, (index) => print("=======tagData[$index]:::${
  tagData["tags"][index]}=============="));
});

结果也同方法一一样，这里代码不同之处在于要使用tagData["title"]，tagData["tags"]，而不是tagData.title，tagData.tags.这是因为Map还没转换成TagData对象,方法一中的过渡就是将Map转换成TagData对象.

方法二没有方法一使用起来方便.

方法三、开始还想到过另外一种方法，当时是因为还不清楚解析List<对象>的数据,就想着外面再套一层,使得对象中有一个数组字段,完整model如下:

class TagList {
  TagList();

  List<TagData> list = [];//这里的list要与服务端统一,一般情况下会叫data,我这里只是模拟

  TagList.fromJson(Map<String, dynamic> map) {
    this.list = (map["list"] as List).map((e) => TagData.fromJson(e)).toList();
  }

  Map<String, dynamic> toJson() => <String, dynamic>{"list": this.list};
}

class TagData {
  String title = "";
  List<String> tags = [];

  TagData();

  TagData.fromJson(Map<String, dynamic> map) {
    this.title = map["title"];
    this.tags = (map["tags"] as List).map((e) => e.toString()).toList();
  }

  Map<String, dynamic> toJson() => <String, dynamic>{"title": this.title, "tags": this.tags};
}

对于fromJson和toJson的理解这个链接有说明:https://blog.csdn.net/qq_34707150/article/details/125440101

使用代码:

String jsonData={"list":[{"title":"空间","tags":["矩形房间","干湿分离","多开间进深"]},{"title":"手法","tags":["砖墙","铝膜","木模"]},{"title":"特征","tags":["落地窗","飘窗","普通窗","降板"]},{"title":"建筑","tags":["高层","别墅","复式","联排"]}]}=================
TagList tagList1 = TagList.fromJson(jsonDecode(jsonData));
tagList1.list.forEach((element) {
  print("=======element:::${element.title}==============");
  List.generate(element.tags.length, (index) => print("=======element[$index]:::${element.tags[index]}=============="));
});

运行也能得到方法一的结果,这个就有点小麻烦了,又套了一层,本来是不需要的,个人感觉最好的是方法一.