Android JsonObject Error org.json.JSONException: No value

Question

当在java for Android中读取JSON字符串时，当有值要查找时，它会给出错误"找不到值"。json 字符串来自 (http://ddragon.leagueoflegends.com/cdn/7.24.1/data/en_US/champion.json( 我需要帮助来确定我在读取 JSON 字符串时出错的地方。

我得到的错误如下。

W/System.err: org.json.JSONException: No value for Aatrox
W/System.err:     at org.json.JSONObject.get(JSONObject.java:389)
W/System.err:     at com.icyrelic.lolsummoner.api.LeagueAPI$3.onSuccess(LeagueAPI.java:146)
W/System.err:     at com.icyrelic.lolsummoner.api.LeagueAPI$1.onResponse(LeagueAPI.java:51)
W/System.err:     at com.icyrelic.lolsummoner.api.LeagueAPI$1.onResponse(LeagueAPI.java:41)
W/System.err:     at com.android.volley.toolbox.StringRequest.deliverResponse(StringRequest.java:78)
W/System.err:     at com.android.volley.toolbox.StringRequest.deliverResponse(StringRequest.java:30)
W/System.err:     at com.android.volley.ExecutorDelivery$ResponseDeliveryRunnable.run(ExecutorDelivery.java:106)
W/System.err:     at android.os.Handler.handleCallback(Handler.java:751)
W/System.err:     at android.os.Handler.dispatchMessage(Handler.java:95)
W/System.err:     at android.os.Looper.loop(Looper.java:154)
W/System.err:     at android.app.ActivityThread.main(ActivityThread.java:6776)
W/System.err:     at java.lang.reflect.Method.invoke(Native Method)
W/System.err:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1520)
W/System.err:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1410)

来自联盟API的代码.java

public static void createRequest(String url, final VolleyCallback callback) {

    final StringRequest stringRequest = new StringRequest(Request.Method.GET, url,
            new Response.Listener<String>() {
                @Override
                public void onResponse(String response) {
                    try {
                        Object json = new JSONTokener(response).nextValue();

                        if(json instanceof JSONObject) {
                            callback.onSuccess(new JSONObject(response));
                        } else if(json instanceof  JSONArray) {
                            callback.onSuccess(new JSONArray(response));
                        } else {
                            throw new Exception("Unknown JSON");
                        }

                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
            }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            error.printStackTrace();
        }
    });
    queue.add(stringRequest);
}
private void setupChampionData() {
    createRequest("http://ddragon.leagueoflegends.com/cdn/7.24.1/data/en_US/champion.json", new VolleyCallback() {
        @Override
        public void onSuccess(Object response) {
            JSONObject json = ((JSONObject) response);
            try {
                JSONObject champions = json.getJSONObject("data");

                Iterator<String> temp = champions.keys();
                System.out.println(json.toString());
                while (temp.hasNext()) {
                    String key = temp.next();
                    JSONObject value = ((JSONObject) json.get(key));
                    championData.put(value.getInt("key"), value);
                }


            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    });
}

Answer 1

您正在从错误的对象读取值。试试这个

                JSONObject value = ((JSONObject) champions.get(key));

而不是

                JSONObject value = ((JSONObject) json.get(key));

Answer 2

JSONObject jsonObjectRoot = new JSONObject("Your_Json");
JSONObject jsonObjectData = jsonObjectRoot.getJSONObject("data");
JSONObject jsonObjectAtrox = jsonObjectData.getJSONObject("Aatrox");
JSONObject jsonObjectAtroxInfo = jsonObjectAtrox.getJSONObject("info");

等等...

Answer 3

"type":"champion",
"format":"standAloneComplex",
"version":"7.24.1",
"data":{  
"Aatrox":{  },
"Ahri":{  },
}..     

如果您看到 json 响应"Aatrox"是数据对象中的 JSONObject。修改对象读取器。你可能会得到它。