java - Android:如何从对象名称可能更改的 JSON 响应中检索多个 JSON 对象？

Question

我有以下 JSON 响应 fragment ，用于按 first_name、last_name 和 email 过滤 ListView 。

"data": {

"filters": {
            "first_name": {
                "key": "first_name",
                "label": "First Name",
                "order": 1,
                "values": [
                    "Shaun",
                    "Max",
                    "Tyler"
                ],
                "filter_type": "select"
            },
            "last_name": {
                "key": "last_name",
                "label": "Last Name",
                "order": 2,
                "values": [
                    "Nash",
                    "Mally",
                    "Carick"
                ],
                "filter_type": "select"
            },
            "email": {
                "key": "email",
                "label": "Email",
                "order": 3,
                "values": [
                    "shaun@email.com",
                    "max@email.com",
                    "tyler@email.com"
                ],
                "filter_type": "select"
            }
        },

        ...

}

我的问题是 first_name、last_name 和 email 是自定义过滤器，这意味着这些 JSON 对象名称可以更改。例如，另一个响应可能如下所示:

"data": {

"filters": {
            "age": {
                "key": "age",
                "label": "Age",
                "order": 1,
                "values": [
                    "33",
                    "24",
                    "47"
                ],
                "filter_type": "select"
            },
            "middle_name": {
                "key": "middle_name",
                "label": "Middle Name",
                "order": 2,
                "values": [
                    "Nicholas",
                    "Ava",
                    "George"
                ],
                "filter_type": "select"
            },
            "email": {
                "key": "email",
                "label": "Email",
                "order": 3,
                "values": [
                    "shaun@email.com",
                    "max@email.com",
                    "tyler@email.com"
                ],
                "filter_type": "select"
            }
        },

        ...
}

在这里，使用的自定义过滤器是 age、middle_name 和 email。虽然这些过滤器名称可能不同，但每个过滤器始终有一个 key、label、order、values 和filter_type 字段。

我无法理解如何使用 GSON 正确解析此处的信息。我尝试研究将 JSON 用于 POJO 网站，但我不知道如何应用它，因为过滤器并不总是相同的。我也尝试这样做:

JSONObject dataObject = myJSON.getJSONObject("data");
if(dataObject.has("filters")){
    JSONObject filterJSONObject = dataObject.getJSONObject("filters");
    //I need to retrieve the keys/values for each filter here
}

但这只返回第一个过滤器对象而不是其余的。

任何帮助将不胜感激

Answer 1

我建议采用不同的方法。您可以像这样创建类(名称仅供示例，但字段名称很重要):

public static class Holder {
        private final Filters data;

        public Holder(Filters data) {
            this.data = data;
        }

        public Filters getData() {
            return data;
        }
    }

    public static class Filters {
        private final Map<String, Value> filters;

        public Filters(Map<String, Value> filters) {
            this.filters = filters;
        }

        public Map<String, Value> getFilters() {
            return filters;
        }
    }

    public static class Value {
        private final String label;
        private final int order;

        public Value(String label, int order) {
            this.label = label;
            this.order = order;
        }

        public String getLabel() {
            return label;
        }

        public int getOrder() {
            return order;
        }
    }

以上结构将序列化到您的示例 json 中:

        Value value1 = new Value("label1", 1);
        Value value2 = new Value("label2", 2);
        Map<String, Value> data = new HashMap<>();
        data.put("age", value1);
        data.put("email", value2);
        Filters filters = new Filters(data);

        Gson gson = new GsonBuilder().setPrettyPrinting().create();
        Log.d("json", gson.toJson(new Holder(filters)));

这是日志输出:

{
  "data": {
    "filters": {
      "age": {
        "label": "label1", 
        "order": 1
      }, 
      "email": {
        "label": "label2", 
        "order": 2
      }
    }
  }
}