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while sending array from android to server 1st element sets at server side 0 value but in android it sets correct value what is the solution

server data
android data
I am passing arraylist of srid of all element and post to server using volley request.enter image description here
here is the code
public class AttendenceShowStdList extends AppCompatActivity {
ActivityAttendenceShowStdListBinding AttendenceShowStdList;
ArrayList<AttStdListModel> userlist = new ArrayList<>();
ArrayList<AllStdListsrIdAdmIdModel> list= new ArrayList<>();
ArrayList<AllStdListModel> stdlist = new ArrayList<>();
AttStdListAdapter adapter;
private DatePickerDialog datePickerDialog;
private String date,clid,sectionId,yrId,instId,usid,usType,attdate;
SharedPreferences sharedPreferences_teach;//staff shareprefferece for profile fetch
private static final String SHARED_PREF_NAME_TEACH="myprefteach";
private static final String Key_USID_TEACH = "techusid";
private static final String Key_INSTID_TEACH = "techinstid";
private static final String Key_USTYPE_TEACH = "techustype";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
AttendenceShowStdList= ActivityAttendenceShowStdListBinding.inflate(getLayoutInflater());
setContentView(AttendenceShowStdList.getRoot());
sharedPreferences_teach =getSharedPreferences(SHARED_PREF_NAME_TEACH, Context.MODE_PRIVATE);
instId=sharedPreferences_teach.getString(Key_INSTID_TEACH,null);
usid=sharedPreferences_teach.getString(Key_USID_TEACH,null);
usType=sharedPreferences_teach.getString(Key_USTYPE_TEACH,null);
//getting data from TakeAttendenceAdapter cardview
clid=getIntent().getExtras().getString("ClassId");
sectionId=getIntent().getExtras().getString("sectionId");
Log.d("cliddd",clid);
yrId=getIntent().getExtras().getString("YearId");
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
date = sdf.format(new Date());
Log.d("dttt",date);
userlist = (ArrayList<AttStdListModel>) getModel(false);
adapter = new AttStdListAdapter(this,userlist);
AttendenceShowStdList.rvstdlist.setAdapter(adapter);
AttendenceShowStdList.rvstdlist.setLayoutManager(new LinearLayoutManager(getApplicationContext(), LinearLayoutManager.VERTICAL, false));
// recyclerView.setLayoutManager(new LinearLayoutManager(getApplicationContext()));
// recyclerView.setHasFixedSize(true);
getData();
//toolbar
setSupportActionBar(AttendenceShowStdList.toolbar);
Objects.requireNonNull(getSupportActionBar()).setDisplayShowHomeEnabled(true);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
AttendenceShowStdList.submit.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
submitAttendence();
// Intent intent = new Intent(AttendenceShowStdList.this,SubmitAttendenceActivity.class);
// startActivity(intent);
}
});
}
private List<AttStdListModel> getModel(boolean isSelect){
List<AttStdListModel> list = new ArrayList<>();
for(int i = 0; i < list.size(); i++){
AttStdListModel model = new AttStdListModel();
model.setSelected(isSelect);
// model.setStud_name(String.valueOf(list.get(i)));
model.setAdmi_id(String.valueOf(list.get(i)));
list.add(model);
}
return list;
}
private void getData() {
RequestQueue queue = Volley.newRequestQueue(getApplicationContext());
String url1="https://comzent.in/wonderschoolerp/apis/teacher/get_studteachers_att.php";
StringRequest request = new StringRequest(Request.Method.POST, url1, new com.android.volley.Response.Listener<String>() {
#SuppressLint("NotifyDataSetChanged")
#Override
public void onResponse(String response) {
// Toast.makeText(getContext(), "Data added to API", Toast.LENGTH_SHORT).show();
try {
JSONObject respObj = new JSONObject(response);
JSONArray jsonArray5=respObj.getJSONArray("studatt_details");
Log.d("std details",jsonArray5.toString());
for(int i=0;i<jsonArray5.length();i++){
JSONObject jsonObject=jsonArray5.getJSONObject(i);
String sr_id=jsonObject.optString("sr_id");
String admi_id=jsonObject.optString("admi_id");
String stud_name=jsonObject.optString("stud_name");
String stud_phone=jsonObject.optString("stud_phone");
String stud_email=jsonObject.optString("stud_email");
String attd_status=jsonObject.optString("attd_status");
String attd_reason=jsonObject.optString("attd_reason");
userlist.add(new AttStdListModel(sr_id,admi_id,stud_name,stud_phone,stud_email,
attd_status,attd_reason));
Log.d("s", String.valueOf(userlist));
list.add(new AllStdListsrIdAdmIdModel(sr_id,admi_id,stud_name,stud_phone,stud_email,
attd_status,attd_reason));
}
} catch (JSONException e) {
e.printStackTrace();
}
adapter=new AttStdListAdapter(getApplicationContext(),userlist);
AttendenceShowStdList.rvstdlist.setAdapter(adapter);
adapter.notifyDataSetChanged();
}
}, new com.android.volley.Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(getApplicationContext(), "Fail to get response = " + error, Toast.LENGTH_SHORT).show();
}
}) {
#Override
protected Map<String, String> getParams() {
Map<String, String> params = new HashMap<String, String>();
params.put("get_studattd","1");
params.put("us_id",usid);
params.put("inst_id",instId);
params.put("class_id",clid);
params.put("sec_id",sectionId);
params.put("ay_id",yrId);
params.put("stud_attend_date",date);
return params;
}
};
queue.add(request);
}
//submit attendence
private void submitAttendence() {
RequestQueue queue = Volley.newRequestQueue(getApplicationContext());
String url1="https://comzent.in/wonderschoolerp/apis/teacher/take_studteacher_att.php";
StringRequest request = new StringRequest(Request.Method.POST, url1, new com.android.volley.Response.Listener<String>() {
#Override
public void onResponse(String response) {
// Toast.makeText(getContext(), "Data added to API", Toast.LENGTH_SHORT).show();
try {
JSONObject respObj = new JSONObject(response);
String msg=respObj.getString("message");
Toast.makeText(AttendenceShowStdList.this, msg, Toast.LENGTH_LONG).show();
Log.d("response msg",msg);
if(msg.equals("Attendance Generated Successfully..!")){
finish();
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new com.android.volley.Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(getApplicationContext(), "Fail to get response = " + error, Toast.LENGTH_LONG).show();
Log.d("error msg", String.valueOf(error));
}
}) {
#Override
protected Map<String, String> getParams() {
Map<String, String> params = new HashMap<String, String>();
ArrayList<String> allstdsrid = new ArrayList<String>();
for(int i=0; i < list.size(); i++) {
allstdsrid.add(String.valueOf(list.get(i).getSr_id()));
}
params.put("sr_id", String.valueOf(allstdsrid));
Log.d("params", String.valueOf(params));
Log.d("allstudentsrid", String.valueOf(allstdsrid));
ArrayList<String> allstdadmid = new ArrayList<String>();
for(int i=0; i < list.size(); i++) {
allstdadmid.add(list.get(i).getAdmi_id());
params.put("admission_id", String.valueOf(allstdadmid));
}
Log.d("allstudentsadmid", String.valueOf(allstdadmid));
///selected student list
ArrayList<String> attstd = new ArrayList<String>();
for (int i = 0; i < AttStdListAdapter.userlist.size(); i++) {
if (AttStdListAdapter.userlist.get(i).getSelected()) {
attstd.add(AttStdListAdapter.userlist.get(i).getAdmi_id());
}
}
params.put("student_attend_submit","1");
params.put("class_id",clid);
params.put("sec_id",sectionId);
params.put("ay_id",yrId);
params.put("att_status", String.valueOf(attstd));
Log.d("params", String.valueOf(params));
params.put("stud_attend_date",date);
params.put("inst_id",instId);
params.put("us_id",usid);
params.put("us_type",usType);
return params;
}
};
queue.add(request);
}
//toolbar back to home
public boolean onOptionsItemSelected(#NonNull MenuItem item) {
if(item.getItemId()==android.R.id.home){
finish();
}
return super.onOptionsItemSelected(item);
}
}
After submitting attendance, values of array of srid and admid retrive at server correctly ,problem is that only first record's srid and admid sets to '0' value.There is no problem when same Api is fetch on postman.

ArrayList won't populate ListView but I can display the items added to ArrayList

I don't know why the items added to ArrayList won't populate ListView, I tried checking if items are indeed added to ArrayList but it shows it does.
You can check the image of the added items here
Here is my code. I'm using another xml for checkedtextview so my listview will display items with checkboxes.
ArrayList<String> symptomsListTest = new ArrayList<>();
ListView chl1;
String URL = "***********";
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_sample);
addListItem();
chl1 = (ListView) findViewById(R.id.checklistSample);
chl1.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);
ArrayAdapter<String> aa = new ArrayAdapter<String>(this, R.layout.symptoms_checklist, R.id.txt_title, symptomsListTest);
//ArrayAdapter<String> aa=new ArrayAdapter<String>(this,R.layout.symptoms_checklist, R.id.txt_title,symptomsListTest);
chl1.setAdapter(aa);
chl1.setOnItemClickListener(new AdapterView.OnItemClickListener()
{
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id)
{
String selectedItem = ((TextView) view).getText().toString();
if(symptomsListTest.contains(selectedItem))
{
symptomsListTest.remove(selectedItem); //remove deselected item from the list of selected items
}
else
{
symptomsListTest.add(selectedItem); //add selected item to the list of selected items
}
}
});
}
public void addListItem()
{
StringRequest stringRequest = new StringRequest(Request.Method.POST, URL,
new Response.Listener<String>()
{
#Override
public void onResponse(String response)
{
try
{
JSONObject jsonObject = new JSONObject(response);
String success = jsonObject.getString("success");
String message = jsonObject.getString("message");
JSONArray jsonArray = jsonObject.getJSONArray("read");
if(success.equals("1"))
{
for(int i = 0; i < jsonArray.length(); i++)
{
JSONObject object = jsonArray.getJSONObject(i);
String symptom = object.getString("symptom1");
symptomsListTest.add(symptom);
//Toast.makeText(SAMPLE.this, ""+symptom, Toast.LENGTH_SHORT).show();
//Toast.makeText(Login.this, ""+message+"\nYour name is: "+name+"\nYour email is: "+email,Toast.LENGTH_SHORT).show();
}
}
else
{
Toast.makeText(SAMPLE.this, ""+message,Toast.LENGTH_SHORT).show();
}
}
catch (JSONException e)
{
e.printStackTrace();
Toast.makeText(SAMPLE.this, e.toString(),Toast.LENGTH_SHORT).show();
}
}
},
new Response.ErrorListener()
{
#Override
public void onErrorResponse(VolleyError error)
{
Toast.makeText(SAMPLE.this, error.toString(),Toast.LENGTH_SHORT).show();
}
})
{
#Override
protected Map<String, String> getParams() throws AuthFailureError
{
Map<String, String> params = new HashMap<>();
String result="success";
params.put("result", result);
return params;
}
};
RequestQueue requestQueue = Volley.newRequestQueue(this);
requestQueue.add(stringRequest);
}

You are executing an AsyncTask which is giving a response after sometime, meanwhile the code of listView and it's adapter is already executed. You just need to add one line after the for loop like this :-
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject object = jsonArray.getJSONObject(i);
String symptom = object.getString("symptom1");
symptomsListTest.add(symptom);
//Toast.makeText(SAMPLE.this, ""+symptom, Toast.LENGTH_SHORT).show();
//Toast.makeText(Login.this, ""+message+"\nYour name is: "+name+"\nYour email is: "+email,Toast.LENGTH_SHORT).show();
}
//** Add This line **
aa.notifyDataSetChanged();
And make sure your ArrayAdapter is declared global. Hope this helps.

repeatation of data in Listview after calling api everytime

I am calling api to fetch data from server and populating the data into Listview using adapter but data gets double itself everytime api getting called. ie:- on first time api call, list shows data like.
A
B
C
on second time api call, list gets data like..
A
B
C
A
B
C
here is my Fragment:
String GetChatURL = RECEIVING_URL+"receiptID="+userId+"&senderID="+recepientID;
StringRequest stringRequest = new StringRequest(Request.Method.GET, GetChatURL,
new com.android.volley.Response.Listener<String>() {
#Override
public void onResponse(String response) {
Log.d("respose valuee",response);
try {
JSONArray jsonArray = new JSONArray(response);
JSONObject jsonObject = new JSONObject();
JSONObject jsonObject1 = new JSONObject();
for(int i = 0;i<=jsonArray.length();i++) {
final ChatReceivingBean chatReceivingBean = new ChatReceivingBean();
jsonObject = jsonArray.getJSONObject(i);
chatReceivingBean.setMessageText(jsonObject.getString("MessageText"));
chatReceivingBean.setSenderID (jsonObject.getString ("senderID"));
chatArrayList.add (chatReceivingBean);
String id = chatReceivingBean.getSenderID ();
adapter = new ChatAdapter (getActivity(),chatArrayList,id);
messagesContainer.setAdapter(adapter);
scroll();
}
Log.e("stringgggg ",chatArrayList.toString ());
} catch (JSONException e) {
e.printStackTrace();
}
}
},
new com.android.volley.Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(getActivity(),error.toString(),Toast.LENGTH_LONG ).show();
}
})
{
#Override
protected Map<String, String> getParams() throws AuthFailureError {
Map<String,String> map = new HashMap<String,String>();
map.put(KEY_CHAT_RECEIVE_USERID,userId);
map.put(KEY_CHAT_RECEIVE_SENDERID,recepientID);
return map;
}
};
try {
RequestQueue requestQueue = Volley.newRequestQueue (getActivity ());
requestQueue.add (stringRequest);
}catch (Exception e){
}
Here is Adapter class:
#Override
public View getView(int position, View convertView, ViewGroup parent) {
sharedPreferences = context.getApplicationContext().getSharedPreferences("MyPref", MODE_PRIVATE);
recepientID = sharedPreferences.getString("key_id",null);
userId = sharedPreferences.getString("key_name",null);
Log.d ("recepientID",recepientID);
Log.d ("userId",userId);
String iid = chatReceivingBeen.get (position).getSenderID ();
View v=convertView;
if(v==null)
{
if(chatReceivingBeen.get (position).getSenderID().equalsIgnoreCase(recepientID)){
//v = View.inflate(cxt, R.layout.right, null);
v= View.inflate (context, R.layout.list_item_chat_other,null);
}else {
// v = View.inflate(cxt, R.layout.left, null);
v= View.inflate (context, R.layout.list_item_chat,null);
}
}
txtMessage = (TextView)v.findViewById(R .id.txtMessage);
if(chatReceivingBeen!=null) {
// holder.txtMessage.setText (chatReceivingBeen.get (position).getMessageText ());
txtMessage.setText (chatReceivingBeen.get (position).getMessageText ());
}
return v;
}

clear chatArrayList before adding to it:
StringRequest stringRequest = new StringRequest(Request.Method.GET, GetChatURL,
new com.android.volley.Response.Listener<String>() {
#Override
public void onResponse(String response) {
Log.d("respose valuee",response);
try {
//clear
chatArrayList.clear()
JSONArray jsonArray = new JSONArray(response);
JSONObject jsonObject = new JSONObject();
JSONObject jsonObject1 = new JSONObject();
....

My app crashes when there is no value in my JSON

I'm posting "id" value (which i pass to this activity via getintent)
Uid = getIntent().getStringExtra("id");
to server and retrieving the corresponding jsonobjects.
#Override
protected Map<String, String> getParams() {
Map<String, String> params = new HashMap<String, String>();
params.put("id", Uid);
return params;
}
When my jsonarray is empty, my app crashes. I want to toast"Error" when jsonarray is empty. How can I fix this?
Here is my code:
public class kill extends FragmentActivity {
GridView grid1;
CustomGrid_Album adapter;
private ProgressDialog pDialog;
String Uid,Disp;
public String category;
public String selected;
public static String imagename;
Button Alb_sel;
ArrayList<Item_album> gridArray = new ArrayList<Item_album>();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.album_display);
grid1 = (GridView) findViewById(R.id.gridView2);
Uid = getIntent().getStringExtra("id");
Disp = getIntent().getStringExtra("disp");
Alb_sel=(Button)findViewById(R.id.album_to_select);
pDialog = new ProgressDialog(kill.this);
pDialog.setMessage("Loading...");
pDialog.show();
//fetching JSONArray
final RequestQueue queue = Volley.newRequestQueue(getApplicationContext());
StringRequest stringRequest = new StringRequest(com.android.volley.Request.Method.POST, AppConfig.URL_Gallery4,
new Response.Listener<String>() {
#Override
public void onResponse(String response) {
Datas.imageIds = new String[response.length()];
JSONArray arr = null;
try {
arr = new JSONArray(response);
} catch (JSONException e1) {
e1.printStackTrace();
}
int i=0;
for (i = 0; i < arr.length(); i++) {
try {
JSONObject obj = arr.getJSONObject(i);
category = obj.getString("category_name");
selected = obj.getString("album_id");
imagename = obj.getString("org_image_name");
Datas.imageIds[i] = AppConfig.URL_IMAGE_temp+obj.getString("album_image").substring(3);
gridArray.add(new Item_album(Datas.imageIds[i]));
} catch (JSONException e) {
e.printStackTrace();
}
}
final int xl = i;
adapter = new CustomGrid_Album(kill.this,xl,gridArray);
adapter.notifyDataSetChanged();
grid1.setAdapter(adapter);
pDialog.dismiss();
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(getApplicationContext(), "No images in this gallery", Toast.LENGTH_SHORT).show();
error.printStackTrace();
}
})
{
#Override
protected Map<String, String> getParams() {
Map<String, String> params = new HashMap<String, String>();
params.put("id", Uid);
return params;
}
};
queue.add(stringRequest);
}
}

apply the check in onResponse
if(response.length()==0){
// error message
}else{
// your rest of the code
}

This looks problematic.
Datas.imageIds = new String[response.length()];
You don't want an array with the size of the string. You want an array of the size of the JSONArray within the response.
public void onResponse(String response) {
JSONArray arr = null;
try {
arr = new JSONArray(response);
Datas.imageIds = new String[arr.length()];
} catch (JSONException e1) {
e1.printStackTrace();
}
However, your code is going to continue on if an exception is thrown there, then you'll end up with a NullPointerException, so you should move the for-loop into the try-catch as well.
Realistically, though, you should just use a JSONArrayRequest if you're going to be expecting a JSONArray.
i want to toast"Error" when jsonarray is empty
Simple enough.
arr = new JSONArray(response);
if (arr.length() == 0) {
// TODO: Toast
}

I would simply add two checks to your onResponse method:
...
public void onResponse(String response) {
// Check if the response itself is an empty string or null
if(TextUtils.isEmpty(response)) {
// Show your user feedback
return;
}
Datas.imageIds = new String[response.length()];
JSONArray arr = null;
try {
arr = new JSONArray(response);
// Check if your JSON has no elements in it
if(arr.length == 0) {
// Show your user feedback
return;
}
} catch (JSONException e1) {
e1.printStackTrace();
}
...

You have declared JSONArray arr = null;
After that you assign the server's JSON to that JSONArray.
Add a line after getting that
if(arr==null)
{
//toast
}
else
{
//whatever you want to do with JSON
}

StringRequest stringRequest = new StringRequest(com.android.volley.Request.Method.POST, AppConfig.URL_Gallery4,
new Response.Listener<String>() {
#Override
public void onResponse(String response) {
if(response.length()==0){
Toast.makeText(getActivity(),"no data found",Toast.LENGTH_SHORT).show();
}
else{
Datas.imageIds = new String[response.length()];
JSONArray arr = null;
try {
arr = new JSONArray(response);
} catch (JSONException e1) {
e1.printStackTrace();
}
if(arr.length()>0){
int i=0;
for (i = 0; i < arr.length(); i++) {
try {
JSONObject obj = arr.getJSONObject(i);
category = obj.getString("category_name");
selected = obj.getString("album_id");
imagename = obj.getString("org_image_name");
Datas.imageIds[i] = AppConfig.URL_IMAGE_temp+obj.getString("album_image").substring(3);
gridArray.add(new Item_album(Datas.imageIds[i]));
} catch (JSONException e) {
e.printStackTrace();
}
}
final int xl = i;
adapter = new CustomGrid_Album(kill.this,xl,gridArray);
adapter.notifyDataSetChanged();
grid1.setAdapter(adapter);
}else{
Toast.makeText(getActivity(),"no data found",Toast.LENGTH_SHORT).show();
}
}
pDialog.dismiss();
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(getApplicationContext(), "No images in this gallery", Toast.LENGTH_SHORT).show();
error.printStackTrace();
}
})
{
#Override
protected Map<String, String> getParams() {
Map<String, String> params = new HashMap<String, String>();
params.put("id", Uid);
return params;
}
};

Use the below code to check whether response is null or not and in object check whether it is having key or data with key is not null
if(response!=null){
try {
Datas.imageIds = new String[response.length()];
JSONArray arr = new JSONArray(response);
for (int i = 0; i < arr.length(); i++) {
try {
JSONObject obj = arr.getJSONObject(i);
if(obj!=null){
if(obj.has("category_name") && !obj.isNull("category_name"){
category = obj.getString("category_name");
}
if(obj.has("album_id") && !obj.isNull("album_id"){
selected = obj.getString("album_id");
}
if(obj.has("org_image_name") && !obj.isNull("org_image_name"){
imagename = obj.getString("org_image_name");
}
if(obj.has("album_image") && !obj.isNull("album_image"){
Datas.imageIds[i] = AppConfig.URL_IMAGE_temp+obj.getString("album_image").substring(3);
gridArray.add(new Item_album(Datas.imageIds[i]));
}
}
} catch (JSONException e) {
e.printStackTrace();
}
}
final int xl = i;
adapter = new CustomGrid_Album(kill.this,xl,gridArray);
adapter.notifyDataSetChanged();
grid1.setAdapter(adapter);
pDialog.dismiss();
} catch (JSONException e1) {
e1.printStackTrace();
}
}

You are using StringRequest, instead of that use JsonArrayRequest to make request as below, so you will get response in onResponse methode when there is a valid JSONArray in response, and if there is no data then you will get response in onError method
JsonArrayRequest rReq = new JsonArrayRequest(Request.Method.GET,"url", new JSONObject(), new Response.Listener() {
#Override
public void onResponse(JSONArray response) {
Log.e(TAG, "onResponse: "+response.toString() );
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Log.e(TAG, "onErrorResponse: "+error.getMessage() );
}
})

Android - Same JSON parsing class for different web services

I have made a JSONParse class for parsing JSON response. I have to call 3 web services. But I want to use only that SINGLE class for parsing JSON response for all 3 web services. All 3 web services has different keys and values. What I have done is like below..
MainActivity.java
public class MainActivity extends AppCompatActivity implements AdapterView.OnItemClickListener {
// Anything Else Goes Here
private ArrayList<ModelCourse> ArrayListModelCourses;
// Variables
private String url = "stream.php";
private String career_path = "";
// Widgets
private ListView lv;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
init();
}
private void init() {
initialisation();
find_view_by_id();
clickListners();
fetchData();
}
private void initialisation() {
ArrayListModelCourses = new ArrayList<>();
}
private void find_view_by_id() {
lv = (ListView) findViewById(R.id.list_view);
}
private void clickListners() {
lv.setOnItemClickListener(this);
}
private void fetchData() {
StringRequest stringReq = new StringRequest(Request.Method.POST, Constants.base_url + url, new Response.Listener<String>() {
#Override
public void onResponse(String response) {
try {
JSONObject jo = new JSONObject(response);
if (jo.has("success")) {
JsonParse jsonParse = new JsonParse(response);
ArrayListModelCourses = jsonParse.parseJson();
} else {
Toast.makeText(MainActivity.this, "Error msg from server!!", Toast.LENGTH_LONG).show();
}
} catch (JSONException e) {
e.printStackTrace();
}
CustomAdapter ca = new CustomAdapter(getApplicationContext(), ArrayListModelCourses);
lv.setAdapter(ca);
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(MainActivity.this, "Error:" + error.getMessage(), Toast.LENGTH_LONG).show();
}
}) {
#Override
protected Map<String, String> getParams() {
Map<String, String> params = new HashMap<String, String>();
params.put("user_id", "51");
return params;
}
};
RequestQueue queue = Volley.newRequestQueue(this);
queue.add(stringReq);
}
#Override
public void onItemClick(AdapterView<?> adapterView, View view, int position, long id) {
String stream_name = ArrayListModelCourses.get(position).getmCourse_name();
String stream_id = ArrayListModelCourses.get(position).getmCourse_id();
career_path += stream_name + ", ";
fetchData();
}
}
JsonParse.java - The single class that I want to use for 3 web services.
public class JsonParse {
// Anything Else Goes Here
ArrayList<ModelCourse> modelCourses = new ArrayList<>();
// Variables
public static final String KEY_ARRAY = "stream_name";
public static final String KEY_ID = "stream_id";
public static final String KEY_NAME = "stream_name";
private String mJsonRes;
public JsonParse(String jsonRes) {
this.mJsonRes = jsonRes;
}
public ArrayList<ModelCourse> parseJson() throws JSONException {
JSONObject jo = new JSONObject(mJsonRes);
JSONArray ja = jo.getJSONArray(KEY_ARRAY);
for (int i = 0; i < ja.length(); i++) {
ModelCourse modelCourseObj = new ModelCourse();
JSONObject object = ja.getJSONObject(i);
modelCourseObj.mCourse_id = object.getString(KEY_ID);
modelCourseObj.mCourse_name = object.getString(KEY_NAME);
modelCourses.add(modelCourseObj);
}
return modelCourses;
}
}
Thanks in advance.

Use can use Gson for mapping json data to objects.
Create models classes for your json data. (use link http://www.jsonschema2pojo.org/)
Now in your MainActivity onResponse() method pass the string response to JsonParse class.
In JsonParse class parse your json data
Gson gson = new Gson();
gson.fromJson(jsonString, JsonModelRootClassName.class);
You can create one method to get "JsonModelRootClassName" based on your web services call.