Question

我有以下JSON字符串：

{
    "error":false,
    "message":"modules retrieved successfully",
    "subjectsEnrolled":
    {
        "studentNumber":"PT2014-1282",
        "courseId":1,
        "moduleNames":["Internet Programming and E-commerce","Operating Systems","Java and Distributed Systems"]
    }
}

我希望检索moduleNames中的值。

尝试检索值的当前方法是：

@Override
protected void onPostExecute(String s) {

    super.onPostExecute(s);

    try {

        JSONObject object = new JSONObject(s);
        JSONArray array = object.getJSONArray("moduleNames");

        if (!object.getBoolean("error")) {
            Toast.makeText(getActivity(), object.getString("message"), Toast.LENGTH_SHORT).show();

        } else {
        }
    } catch (JSONException e) {
        e.printStackTrace();
        Log.e("JSON Parser", "Error parsing data " + e.toString());
    }
}

遵循以下追踪：

10-29 20:48:50.741 14484-14484/com.example.vhuhwavho.mylms W/System.err: org.json.JSONException: No value for moduleNames
10-29 20:48:50.741 14484-14484/com.example.vhuhwavho.mylms W/System.err:     at org.json.JSONObject.get(JSONObject.java:355)
10-29 20:48:50.741 14484-14484/com.example.vhuhwavho.mylms W/System.err:     at org.json.JSONObject.getJSONArray(JSONObject.java:549)
10-29 20:48:50.741 14484-14484/com.example.vhuhwavho.mylms W/System.err:     at com.example.vhuhwavho.mylms.ModulesFragment$PerformNetworkRequest.onPostExecute(ModulesFragment.java:166)
10-29 20:48:50.741 14484-14484/com.example.vhuhwavho.mylms W/System.err:     at com.example.vhuhwavho.mylms.ModulesFragment$PerformNetworkRequest.onPostExecute(ModulesFragment.java:137)
10-29 20:48:50.741 14484-14484/com.example.vhuhwavho.mylms W/System.err:     at android.os.AsyncTask.finish(AsyncTask.java:632)
10-29 20:48:50.741 14484-14484/com.example.vhuhwavho.mylms W/System.err:     at android.os.AsyncTask.access$600(AsyncTask.java:177)
10-29 20:48:50.741 14484-14484/com.example.vhuhwavho.mylms W/System.err:     at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:645)
10-29 20:48:50.741 14484-14484/com.example.vhuhwavho.mylms W/System.err:     at android.os.Handler.dispatchMessage(Handler.java:102)
10-29 20:48:50.741 14484-14484/com.example.vhuhwavho.mylms W/System.err:     at android.os.Looper.loop(Looper.java:146)
10-29 20:48:50.741 14484-14484/com.example.vhuhwavho.mylms W/System.err:     at android.app.ActivityThread.main(ActivityThread.java:5487)
10-29 20:48:50.741 14484-14484/com.example.vhuhwavho.mylms W/System.err:     at java.lang.reflect.Method.invokeNative(Native Method)
10-29 20:48:50.741 14484-14484/com.example.vhuhwavho.mylms W/System.err:     at java.lang.reflect.Method.invoke(Method.java:515)
10-29 20:48:50.746 14484-14484/com.example.vhuhwavho.mylms W/System.err:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1283)
10-29 20:48:50.746 14484-14484/com.example.vhuhwavho.mylms W/System.err:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099)
10-29 20:48:50.746 14484-14484/com.example.vhuhwavho.mylms W/System.err:     at dalvik.system.NativeStart.main(Native Method)
10-29 20:48:50.746 14484-14484/com.example.vhuhwavho.mylms E/JSON Parser: Error parsing data org.json.JSONException: No value for moduleNames

有什么建议吗？

Answer 1

JsonArray位于JsonObject内部，因此您必须先获取内部对象 subjectEnrolled ，然后按如下方式获取数组：

    JSONObject root_object = new JSONObject(s);
    JSONObject object = root_object.getJSONObject("subjectsEnrolled");
    JSONArray array = object.getJSONArray("moduleNames");

Answer 2

试试这个

    JSONObject object = new JSONOBject(s);
    String error = object.getString("error");
    String message = object.getString("message");

    JSONObject obj2 = object.getJSONObject("subjectsEnrolled");
    String studentnumber = obj2.getString("studentNumber");
    String courseid = obj2.getString("courseId");


    JSONArray jarr1 = obj2.getJSONArray("moduleNames");
    Log.d("checkjsonarrayresponsehere==", ""+jarr1);

Answer 3

检查一下，如上所述，你必须先得到内部对象然后需要一个类似于此的步骤来读取数组中的每个值。

   for(JsonValue value : arrObj){
      System.out.println(value.toString());
   }

http://www.java2novice.com/java-json/javax.json/read-json-array/

从JSONArray中检索数组

3 个答案: