当我在 post 方法上点击 api 时得到空对象响应
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【中文标题】当我在 post 方法上点击 api 时得到空对象响应【英文标题】：Getting null object response when i hit the api on post method 【发布时间】：2019-11-18 17:19:51 【问题描述】：我有一些 json 数据，我正在尝试通过 api 响应 json。但是当我试图得到回应时，每次 得到 W/System.err: org.json.JSONException: No value for cadet_details 这个错误在我的 android studio logcat 上。帮我怎么做 得到这个回应。
我的活动代码：-
private void ncccadetlist(int i)
mHandler.sendEmptyMessage(SHOW_PROG_DIALOG);
progress_dialog_msg = "loading...";
String Url = "http://www.tsassessors.in/nccwork/API/cadre_sign_up_login/getApprovedCadetsListByInstitute.php";
StringRequest stringRequest = new StringRequest(Request.Method.GET, Url,
new Response.Listener<String>()
@Override
public void onResponse(String s)
try
JSONObject json = new JSONObject(s);
Log.d("status", s);
String status = json.getString("status");
String msg = json.getString("msg");
if (json.getString("status").equals("0"))
Log.d("step1", "cadets");
JSONArray jsonArray = json.getJSONArray("cadet_details");
for (int i = 0; i < jsonArray.length(); i++)
JSONObject localJson = jsonArray.getJSONObject(i);
CadetDetail cadetDetail = new CadetDetail();
cadetDetail.setCadetName(localJson.getString("cadet_name"));
cadetDetail.setEnrollmentNo(localJson.getString("enrollment_no"));
cadetDetail.setIsIsoUploaded(localJson.getString("is_iso_uploaded"));
cadetDetailsArray.add(cadetDetail);
progress_dialog.dismiss();
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
else
FancyToast.makeText(context, "" + msg , FancyToast.LENGTH_LONG, FancyToast.ERROR, false).show();
catch (JSONException e)
e.printStackTrace();
,
new Response.ErrorListener()
@Override
public void onErrorResponse(VolleyError volleyError)
FancyToast.makeText(context,"Some issue in loading",FancyToast.LENGTH_LONG,FancyToast.ERROR,false).show();
)
@Override
protected Map<String, String> getParams() throws AuthFailureError
Map<String, String> params = new Hashtable<String, String>();
Log.d("Final", "history of api");
params.put("instt_id", insttId );
params.put("ncc_year", "2" );
return params;
;
RequestQueue requestQueue = Volley.newRequestQueue(this);
requestQueue.add(stringRequest);
CadetDetail.java
package com.tsa.ncc_dte_punjab.models;
import java.util.HashMap;
import java.util.Map;
public class CadetDetail
private String cadetName;
private String status;
private String msg;
private String enrollmentNo;
private String isIsoUploaded;
private Map<String, Object> additionalProperties = new HashMap<String, Object>();
public String getCadetName()
return cadetName;
public void setCadetName(String cadetName)
this.cadetName = cadetName;
public String getEnrollmentNo()
return enrollmentNo;
public void setEnrollmentNo(String enrollmentNo)
this.enrollmentNo = enrollmentNo;
public String getIsIsoUploaded()
return isIsoUploaded;
public void setIsIsoUploaded(String isIsoUploaded)
this.isIsoUploaded = isIsoUploaded;
public Map<String, Object> getAdditionalProperties()
return this.additionalProperties;
public String getStatus()
return status;
public void setStatus(String status)
this.status = status;
public String getMsg()
return msg;
public void setMsg(String msg)
this.msg = msg;
public void setAdditionalProperty(String name, Object value)
this.additionalProperties.put(name, value);
JSON 响应：-
"status": "1",
"cadet_details": [
"cadet_name": "AJIT SINGH",
"enrollment_no": "",
"is_iso_uploaded": "0"
,
"cadet_name": "AKASH",
"enrollment_no": "",
"is_iso_uploaded": "0"
,
"cadet_name": "AKASH",
"enrollment_no": "",
"is_iso_uploaded": "0"
,
"cadet_name": "AKASH ",
"enrollment_no": "",
"is_iso_uploaded": "0"
,
]
错误：
2019-07-09 12:58:22.243 11818-11818/com.tsa.ncc_dte_punjab W/.ncc_dte_punjab: type=1400 audit(0.0:79109): avc: denied getattr for path="/dev/sw_sync" dev="tmpfs" ino=6638 scontext=u:r:untrusted_app:s0:c512,c768 tcontext=u:object_r:sw_sync_device:s0 tclass=chr_file permissive=0
2019-07-09 12:58:22.250 11818-11818/com.tsa.ncc_dte_punjab D/status:
"status":"0","msg":"Please select NCC Year"
2019-07-09 12:58:22.250 11818-11818/com.tsa.ncc_dte_punjab D/step1: cadets
2019-07-09 12:58:22.250 11818-11818/com.tsa.ncc_dte_punjab W/System.err: org.json.JSONException: No value for cadet_details
2019-07-09 12:58:22.256 11818-11818/com.tsa.ncc_dte_punjab W/System.err: at org.json.JSONObject.get(JSONObject.java:389)
2019-07-09 12:58:22.256 11818-11818/com.tsa.ncc_dte_punjab W/System.err: at org.json.JSONObject.getJSONArray(JSONObject.java:584)
2019-07-09 12:58:22.256 11818-11818/com.tsa.ncc_dte_punjab W/System.err: at com.tsa.ncc_dte_punjab.activities.AttendanceActivity$5.onResponse(AttendanceActivity.java:327)
2019-07-09 12:58:22.256 11818-11818/com.tsa.ncc_dte_punjab W/System.err: at com.tsa.ncc_dte_punjab.activities.AttendanceActivity$5.onResponse(AttendanceActivity.java:314)
2019-07-09 12:58:22.256 11818-11818/com.tsa.ncc_dte_punjab W/System.err: at com.android.volley.toolbox.StringRequest.deliverResponse(StringRequest.java:82)
2019-07-09 12:58:22.256 11818-11818/com.tsa.ncc_dte_punjab W/System.err: at com.android.volley.toolbox.StringRequest.deliverResponse(StringRequest.java:29)
2019-07-09 12:58:22.256 11818-11818/com.tsa.ncc_dte_punjab W/System.err: at com.android.volley.ExecutorDelivery$ResponseDeliveryRunnable.run(ExecutorDelivery.java:102)
2019-07-09 12:58:22.256 11818-11818/com.tsa.ncc_dte_punjab W/System.err: at android.os.Handler.handleCallback(Handler.java:836)
2019-07-09 12:58:22.257 11818-11818/com.tsa.ncc_dte_punjab W/System.err: at android.os.Handler.dispatchMessage(Handler.java:103)
2019-07-09 12:58:22.257 11818-11818/com.tsa.ncc_dte_punjab W/System.err: at android.os.Looper.loop(Looper.java:203)
2019-07-09 12:58:22.257 11818-11818/com.tsa.ncc_dte_punjab W/System.err: at android.app.ActivityThread.main(ActivityThread.java:6251)
2019-07-09 12:58:22.257 11818-11818/com.tsa.ncc_dte_punjab W/System.err: at java.lang.reflect.Method.invoke(Native Method)
2019-07-09 12:58:22.257 11818-11818/com.tsa.ncc_dte_punjab W/System.err: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1063)
2019-07-09 12:58:22.257 11818-11818/com.tsa.ncc_dte_punjab W/System.err: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:924)
I am trying to help by Editing , Just change the Method Of Request
from GET to POST because GET not Passing any Parameter
with Request so that response will be status 0
the another thing int insttId = 1;
define some where in your code your will get success response with status 1. ```
【问题讨论】：
您发布的 json 响应是正确的。在此处检查您的 json 响应https://jsonlint.com/
你有没有为此提供任何参数？
【参考方案1】：
只需改变这个-：
json.getString("status").equals("0")
到：
json.getString("status").equals("1")
【讨论】：
【参考方案2】：您没有正确加载 JSON 文件。使用这个：
try
JSONObject obj = null;
obj = new JSONObject(FileUtils.readFileRoot(AppConstants.CONFIG_FILE_NAME, this));
//Load the config file
catch (JSONException e)
Crashlytics.getInstance().core.logException(e);
// Issue #627
// added the catch exception to check the config and throwing back to setup activity
Toast.makeText(getApplicationContext(), "JsonException" + e, Toast.LENGTH_LONG).show();
showAlertDialogButtonClicked(e.toString());
我的配置文件声明是：
public static String CONFIG_FILE_NAME = "config.json";
如果有用请点赞！
【讨论】：
【参考方案3】：首先：这是一个 GET 请求，而不是您在代码中提到的 POST。
StringRequest stringRequest = new StringRequest(Request.Method.GET, Url,
第二：对于 GET 请求，api 返回这个 json 响应
"status":"0","msg":"Please select NCC Year"
在此响应中不包含 cadet_details 对象。
您需要像这样更改您的代码：
try
JSONObject json = new JSONObject(s);
Log.d("status", s);
String status = json.getString("status");
if (!status.equals("0"))
Log.d("step1", "cadets");
JSONArray jsonArray = json.getJSONArray("cadet_details");
for (int i = 0; i < jsonArray.length(); i++)
JSONObject localJson = jsonArray.getJSONObject(i);
CadetDetail cadetDetail = new CadetDetail();
cadetDetail.setCadetName(localJson.getString("cadet_name"));
cadetDetail.setEnrollmentNo(localJson.getString("enrollment_no"));
cadetDetail.setIsIsoUploaded(localJson.getString("is_iso_uploaded"));
cadetDetailsArray.add(cadetDetail);
progress_dialog.dismiss();
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
else
String msg = json.getString("msg");
FancyToast.makeText(context, "" + msg , FancyToast.LENGTH_LONG, FancyToast.ERROR, false).show();
catch (JSONException e)
e.printStackTrace();
【讨论】：
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