android volley JsonArrayRequest return nothing - android-volley

Question

in the below code my arrayList will be empty after JsonArrayRequest block.
I set break point at this line: "int size = arrayList.size();"
every thing is OK until "while" loop finishes. after that allayList is empty.
JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(Request.Method.GET, json_url,(String) null,
new Response.Listener<JSONArray>() {
#Override
public void onResponse(JSONArray response) {
int count=0;
int responseLength = response.length();
responseLength--;
while (count<responseLength)
{
try {
JSONObject jsonObject = response.getJSONObject(count);
Contact contact = new Contact(jsonObject.getString("title"),
jsonObject.getString("email"),
jsonObject.getString("description"),
jsonObject.getString("date"),
jsonObject.getBoolean("status"));
arrayList.add(contact);
int size = arrayList.size();
count++;
} catch (JSONException e) {
e.printStackTrace();
}
}
int size = arrayList.size();
}
},
new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(context,"Error....",Toast.LENGTH_SHORT).show();
error.printStackTrace();
}
}
);
int size = arrayList.size();
VolleySingleton.getmInstance(context).addToRequestQueue(jsonArrayRequest);
return arrayList;

Answer 1

I will show what i did using CallBack interface:
in onCreate() method:
recyclerView = (RecyclerView) findViewById(R.id.recyclerview);
recyclerView.setHasFixedSize(true);
LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
recyclerView.setLayoutManager(linearLayoutManager);
BackgroundTask backgroundTask = new BackgroundTask(this);
backgroundTask.getContacts(new BackgroundTask.arrayListCallBack() {
#Override
public void onSuccess(ArrayList<Contact> contacts) {
RecyclerView.Adapter adapter = new RecyclerAdapter(MainActivity.this, contacts);
recyclerView.setAdapter(adapter);
}
#Override
public void onFail(String error) {
Toast.makeText(MainActivity.this, error, Toast.LENGTH_LONG).show();
}
});
and in the BackgroundTask class:
JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(Request.Method.POST, server_url, new Response.Listener<JSONArray>() {
#Override
public void onResponse(JSONArray response) {
int count = 0;
while (count < response.length()) {
try {
JSONObject jsonObject = response.getJSONObject(count);
Contact contact = new Contact(jsonObject.getString("name"), jsonObject.getString("section"));
contacts.add(contact);
Log.d("process request", "....."+jsonObject.getString("name"));
count++;
} catch (JSONException e) {
e.printStackTrace();
Toast.makeText(context, e.getMessage()+"\nError in Response", Toast.LENGTH_LONG).show();
}
callBack.onSuccess(contacts);
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
error.printStackTrace();
Toast.makeText(context, error.getMessage()+"\nError in Connection", Toast.LENGTH_LONG).show();
callBack.onFail("There's error ...");
}
});
MySingleton.getInstance(context).addToRequestQueue(jsonArrayRequest);
}
public interface arrayListCallBack {
void onSuccess(ArrayList<Contact> contacts);
void onFail(String error);
}