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 响应片段，用于按 first_name、last_name 和 email.

过滤列表视图

"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"
            }
        },

        ...
}

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。我尝试研究使用 JSON 到 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。我也在尝试这样做：

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
}

但这只是 returns 第一个过滤器对象而不是其余的。

如有任何帮助，我们将不胜感激

Answer 1

您可以像下面这样查看

    JSONObject firstNameFilter = filterJSONObject.getJSONObject("first_name");
    JSONObject ageFilter = filterJSONObject.getJSONObject("age");

    if(firstNameFilter != null){
    }

    if(ageFilter != null){
    }

Answer 2

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中 json:

        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
      }
    }
  }
}

Answer 3

您可以使用 keys() 方法

获得包含 JSONObject 中键列表的迭代器

Answer 4

你可以试试这个方法

Map<String, Object> filterMap = new HashMap<String, Object>();
if(dataObject.has("filters")){
        JSONObject filterJSONObject = null;
        try {
            filterJSONObject = dataObject.getJSONObject("filters");
        } catch (JSONException e) {
            e.printStackTrace();
        }
        //I need to retrieve the keys/values for each filter here
        Iterator<String> keysItr = filterJSONObject.keys();

        while(keysItr.hasNext()) {
            String key = keysItr.next();
            Object value = null;
            try {
                value = filterJSONObject.get(key);
            } catch (JSONException e) {
                e.printStackTrace();
            }

           if(value instanceof JSONObject) {
                value = togetValueMap((JSONObject) value);
            }
            filterMap.put(key, value);
        }
    }

  private ArrayList<FilterValue> togetValueMap(JSONObject value) {

        ArrayList<FilterValue> arrayList = new ArrayList<FilterValue>();
        List<String> list = new ArrayList<String>(); 

          for (int i = 0; i < value.length(); i++) {
            FilterValue filterValue = new FilterValue();

            try {
                filterValue.setKey(value.getString("key"));
                filterValue.setLabel(value.getString("label"));
                filterValue.setOrder(value.getInt("order"));
               filterValue.setFilter_type(value.getString("filter_type"));
                JSONArray  jsonArray =  value.getJSONArray("values");

                for (int j=0; j<jsonArray.length(); j++) {
                    list.add(jsonArray.getString(j) );
                }
                filterValue.setValues(list);
                arrayList.add(filterValue);
            } catch (JSONException e) {
                e.printStackTrace();
            }
        }
        return arrayList;
    }

public static class FilterValue {
    private String key;
    private String label;
    private int order;
    private List<String> values;
    private String filter_type;

    public void setKey(String key) {
        this.key = key;
    }

    public void setLabel(String label) {
        this.label = label;
    }

    public void setOrder(int order) {
        this.order = order;
    }

    public void setValues(List<String> values) {
        this.values = values;
    }

    public void setFilter_type(String filter_type) {
        this.filter_type = filter_type;
    }
    public String getKey() {
        return key;
    }

    public String getLabel() {
        return label;
    }

    public int getOrder() {
        return order;
    }

    public List<String> getValues() {
        return values;
    }

    public String getFilter_type() {
        return filter_type;
    }
}

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

Android: How to retrieve multiple JSON objects from a JSON response in which object names might change?

java

android

json

gson

retrofit