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How to update array adapter using timer/handler?

I get the data from API such as printer name, model and status and displaying in the listview in array adapter.In my program I am testing if the printer is idle or not and showing by using green(idle) and red (busy) circles in the listview , but my issue is that the state has to be constantly checked and get updated to display on screen green or red circle, for this case I was checking out into handler and timers and tried to implement it but unsuccessfully - nothing worked. I am unsure which one is better to use and how , since I am using array adapter.
If you have any insights, please let me know.
My adapter class:
public class NsdServiceInfoAdapter extends ArrayAdapter<PrinterNew> {
private Context mContext;
private List<PrinterNew> services;
private InetAddress hostAddress;
//Creating new constructor with parameters such as this class(context), layout id (list item layout Id) and data model.
public NsdServiceInfoAdapter(#NonNull Context context, int layoutId, List<PrinterNew> list) {
super(context, layoutId, list);
mContext = context;
services = list;
}
#NonNull
#Override
public View getView(int position, #Nullable View convertView, #NonNull
ViewGroup parent) {
View listItem = convertView;
//Checking if view is empty then we inflate our list layout.
if (listItem == null)
listItem =
LayoutInflater.from(mContext).inflate(R.layout.list_item, parent, false);
//Getting data's position in the data set.
final PrinterNew currentService = services.get(position);
final ImageView i = listItem.findViewById(R.id.status_circle);
TextView t = listItem.findViewById(R.id.TextView_serviceName);
final TextView r = listItem.findViewById(R.id.TextView_serviceIP);
r.setText(currentService.getPrinterModel());
t.setText(currentService.getPrinterName());
if (currentService.isIdle()) {
i.setColorFilter(Color.rgb(42, 187, 155));
} else {
i.setColorFilter(Color.rgb(240, 52, 52));
}
return listItem;
}
}
My printer class
public PrinterNew() {
}
public String getPrinterName() {
return printerName;
}
public void setPrinterName(String printerName) {
this.printerName = printerName;
}
public String getPrinterModel() {
return printerModel;
}
public String getPrinterInformation() {
return this.printInformation;
}
public void setPrinterInformation(String url, Context context, final VolleyCallback callback) {
Log.d("API", "Currently calling URL " + url);
RequestQueue queue = Volley.newRequestQueue(context);
queue.add(new StringRequest(Request.Method.GET, url, new Response.Listener<String>() {
#Override
public void onResponse(String response) {
Log.d("API", "Print information" + response);
String temp = response.substring(2, response.length() - 2);
byte msgArray[];
try {
msgArray = temp.getBytes("ISO-8859-1");
state = msgArray[0];
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
printInformation = response;
callback.onSuccess(printInformation);
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Log.d("API", "Print information nope ");
callback.onFailure(error);
}
}));
}
public String getMenuInformation() {
return menuInformation;
}
public void setMenuInformation(String url, Context context, final VolleyCallback callback) {
Log.d("API", "Currently calling URL " + url);
RequestQueue queue = Volley.newRequestQueue(context);
queue.add(new StringRequest(Request.Method.GET, url, new Response.Listener<String>() {
#Override
public void onResponse(String response) {
String temp = response.substring(2, response.length() - 2);
Log.d("API", "Current menu" + response);
byte msgArray[];
try {
msgArray = temp.getBytes("ISO-8859-1");
currentMenu = msgArray[0];
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
menuInformation = response;
callback.onSuccess(menuInformation);
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Log.d("API", "Current menu Nope ");
callback.onFailure(error);
}
}));
}
public boolean isIdle() {
if (state == -1 && currentMenu == 0) {
return true;
} else {
return false;
}
}
public void setPrinterService(NsdServiceInfo service) {
this.printerService = service;
}
public NsdServiceInfo getPrinterService() {
return this.printerService;
}
public interface VolleyCallback {
void onSuccess(String result);
void onFailure(Object response);
}
public void setPrinterModel(String url, Context context, final VolleyCallback callback) {
Log.d("API", "Currently calling URL " + url);
RequestQueue queue = Volley.newRequestQueue(context);
queue.add(new StringRequest(Request.Method.GET, url, new Response.Listener<String>() {
#Override
public void onResponse(String response) {
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Log.d("API", "printer model nope ");
callback.onFailure(error);
}
}));
}
}

use recyclerview.
to refresh your list whenever there is data change in the list with recyclerview, you need to user adapter.notifyDataSetChanged()
but catch here is you need to get exact object in the list, the update it then refresh it with above line.
Hope this helps.

How to call more than one api in single activity by making separate class for all volley operations

I have created a separate class in which I have defined all about volley and in another activity, I have directly pass URL, CONTEXT and Get Response...
but in my NavDrawerActivity.java how do I call the subCategoryJSON(); method without writing my volley code again as I have done with mainCategoryJSON(); method in which I just simply pass the URL, method type.
Also is this a correct approach I am doing or there need to be some modification in the code, what I want is that wherever I am using API in my project and using volley for it, I don't have to write code again and again just simply pass the URL,method type
VolleyResponseListener.java
public interface VolleyResponseListener {
void onResponse(String response, String tag);
void onError(VolleyError error, String tag);
}
CustomStringRequestVolley.java
public class CustomStringRequestVolley {
private String url;
private String tag;
Context ctx;
private VolleyResponseListener volleyResponseListener;
public CustomStringRequestVolley(String url, String tag,Context ctx,VolleyResponseListener volleyResponseListener){
this.url = url;
this.tag = tag;
this.ctx=ctx;
this.volleyResponseListener = volleyResponseListener;
sendRequest();
}
private void sendRequest() {
final ProgressDialog pDialog = new ProgressDialog(ctx);
pDialog.setMessage("Loading ...");
pDialog.show();
StringRequest stringRequest = new StringRequest(Request.Method.GET,url,
new Response.Listener<String>() {
#Override
public void onResponse(String response) {
Log.e("catresponse", "response " + response);
if (pDialog.isShowing()) {
pDialog.dismiss();
}
volleyResponseListener.onResponse(response, tag);
}
},
new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
error.printStackTrace();
}
});
stringRequest.setRetryPolicy(new DefaultRetryPolicy(
5000,
DefaultRetryPolicy.DEFAULT_MAX_RETRIES,
DefaultRetryPolicy.DEFAULT_BACKOFF_MULT));
VolleySingleton.getInstance(ctx).addToRequestQueue(stringRequest);
}
}
NavDrawerActivity.java
public class NavDrawerActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener, VolleyResponseListener {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_nav_drawer);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
mainCategoryJSON();
subCategoryJSON();
}
private void mainCategoryJSON() {
CustomStringRequestVolley request1 = new CustomStringRequestVolley(URLs.categoryURL, "TAG1", this, this);
}
#Override
public void onResponse(String response, String tag) {
switch (tag) {
case "TAG1":
try {
Log.i("Responseeeeeezaq :", response.toString() + " " + tag);
JSONObject obj = new JSONObject(response);
JSONArray productArray = obj.getJSONArray("categories");
for (int i = 0; i < productArray.length(); i++) {
JSONObject productObject = productArray.getJSONObject(i);
CategoryModelClass categoryModelClass = new CategoryModelClass();
categoryModelClass.setCategoryID(productObject.getInt("Category-Id"));
categoryModelClass.setCategoryName(productObject.getString("Category-Name"));
categoryModelClass.setCategoryImg(productObject.getString("Category-Image"));
categoryArrayList.add(categoryModelClass);
Log.d("zpuyi", String.valueOf(categoryArrayList));
}
categoryAdapter.notifyDataSetChanged();
} catch (Exception e) {
e.printStackTrace();
}
break;
}
}
#Override
public void onError(VolleyError error, String tag) {
VolleyLog.e("Error: ", error.getMessage());
}
private void subCategoryJSON() {
StringRequest stringRequest = new StringRequest(Request.Method.GET, URLs.subcategoryURL,
new Response.Listener<String>() {
#Override
public void onResponse(String response) {
Log.d("subcategoryJsonResponse", response.toString());
try {
JSONObject obj = new JSONObject(response);
JSONArray productArray = obj.getJSONArray("sub-categories");
for (int i = 0; i < productArray.length(); i++) {
JSONObject productObject = productArray.getJSONObject(i);
SubCategoryModelClass subCategoryModelClass = new SubCategoryModelClass();
subCategoryModelClass.setSubCategory_Id(productObject.getInt("Subcategories-Id"));
subCategoryModelClass.setCat_id(productObject.getInt("categories-Id"));
subCategoryModelClass.setSubCategory_Name(productObject.getString("Subcategories-Name"));
subCategoryModelClass.setSubCategory_Img(productObject.getString("Subcategories-Image"));
subCategoryModelClassList.add(subCategoryModelClass);
Log.d("subCategoryArraylist", String.valueOf(subCategoryModelClassList));
}
for (int i = 0; i < subCategoryModelClassList.size(); i++) {
subcategory_id = subCategoryModelClassList.get(i).getSubCategory_Id();
category_id = subCategoryModelClassList.get(i).getCat_id();
subcategory_name = subCategoryModelClassList.get(i).getSubCategory_Name();
// subcategory_desc = subCategoryModelClassList.get(i).getSubCategory_Desc();
subcategory_image = subCategoryModelClassList.get(i).getSubCategory_Img();
Log.d("fdsaff", subcategory_image);
SQLiteDatabase database = dbHelper.getWritableDatabase();
dbHelper.insertSubCategoryProduct(subcategory_id, category_id, subcategory_name, "https://www.ecrm.sample.in/app/img/"+subcategory_image, database);
dbHelper.close();
}
subCategoryAdapter.notifyDataSetChanged();
} catch (JSONException e) {
e.printStackTrace();
}
}
},
new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
VolleyLog.e("Error: ", error.getMessage());
}
});
VolleySingleton.getInstance(getApplicationContext()).addToRequestQueue(stringRequest);
}
}

You have written the answer correctly but you are not implementing the written custom volley class code in the activity class.
First Define the interface class for the Volley as below,
Now implement the volley interface in the java class where you have written the custom volley class as below:
CustomStringRequestVolley.java
public class CustomStringRequestVolley implements volleyCallback {
public Context context;
public CustomStringRequestVolley(Context context) {
this.context = context;
}
public interface volleyCallback {
void onSuccess(String result);
void onError(String error);
}
public void callGetServer(String URL, final
volleyCallback callback){
if (!checkInternetConnection(context)) {
showNoInternetDialogue(context);
return;
}
RequestQueue requestQueue = Volley.newRequestQueue(context);
StringRequest stringRequest = new StringRequest(Request.Method.GET, URL, new
Response.Listener<String>() {
#Override
public void onResponse(String response) {
callback.onSuccess(response);
}
}, error -> {
if (error.networkResponse == null){
if (error.getClass().equals(TimeoutError.class)){
Toast.makeText(context, "Timeout.Please try again",
Toast.LENGTH_SHORT).show();
}else if (error.getClass().equals(NoConnectionError.class)){
Toast.makeText(context, "Timeout.Please try again", Toast.LENGTH_SHORT).show();
}else if (error.getClass().equals(NetworkError.class)) {
Toast.makeText(context, "Network Error.Please try again", Toast.LENGTH_SHORT).show();
}else if (error.getClass().equals(ParseError.class)){
Toast.makeText(context, "Parse error", Toast.LENGTH_SHORT).show();
}else if (error.getClass().equals(ServerError.class)){
Toast.makeText(context, "Server Error.Please try again", Toast.LENGTH_SHORT).show();
}
else {
parseVolleyError(error);
}
}
}
) {
#Override
protected Map<String, String> getParams() {
return new HashMap<>();
}
#Override
public Map<String, String> getHeaders() {
Map<String, String> headers = new HashMap<>();
headers.put("Content-Type", "application/x-www-form-urlencoded");
return headers;
}
};
//setting up the retry policy for slower connections
int socketTimeout = 120000;//120000 milli seconds - change to what you want
RetryPolicy policy = new DefaultRetryPolicy(socketTimeout,
DefaultRetryPolicy.DEFAULT_MAX_RETRIES, DefaultRetryPolicy.DEFAULT_BACKOFF_MULT);
stringRequest.setRetryPolicy(policy);
requestQueue.add(stringRequest);
}
}
Now use this Custom volley class in every activity you required. It reduces you
boilerplate code
NavDrawerActivity.java
CustomStringRequestVolley customStringRequestVolley;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_starting_point_navigation);
customStringRequestVolley = new CustomStringRequestVolley(this);
}
private void subCategoryJSON() {
customStringRequestVolley.callGetServer(URLs.subcategoryURL,new volleyCallback() {
#Override
public void onSuccess(String result) {
try {
JSONObject obj = new JSONObject(response);
JSONArray productArray = obj.getJSONArray("sub-categories");
for (int i = 0; i < productArray.length(); i++) {
JSONObject productObject = productArray.getJSONObject(i);
SubCategoryModelClass subCategoryModelClass = new SubCategoryModelClass();
subCategoryModelClass.setSubCategory_Id(productObject.getInt("Subcategories-Id"));
subCategoryModelClass.setCat_id(productObject.getInt("categories-Id"));
subCategoryModelClass.setSubCategory_Name(productObject.getString("Subcategories-Name"));
subCategoryModelClass.setSubCategory_Img(productObject.getString("Subcategories-Image"));
subCategoryModelClassList.add(subCategoryModelClass);
Log.d("subCategoryArraylist", String.valueOf(subCategoryModelClassList));
}
for (int i = 0; i < subCategoryModelClassList.size(); i++) {
subcategory_id = subCategoryModelClassList.get(i).getSubCategory_Id();
category_id = subCategoryModelClassList.get(i).getCat_id();
subcategory_name = subCategoryModelClassList.get(i).getSubCategory_Name();
// subcategory_desc = subCategoryModelClassList.get(i).getSubCategory_Desc();
subcategory_image = subCategoryModelClassList.get(i).getSubCategory_Img();
Log.d("fdsaff", subcategory_image);
SQLiteDatabase database = dbHelper.getWritableDatabase();
dbHelper.insertSubCategoryProduct(subcategory_id, category_id, subcategory_name, "https://www.ecrm.sample.in/app/img/"+subcategory_image, database);
dbHelper.close();
}
subCategoryAdapter.notifyDataSetChanged();
} catch (JSONException e) {
e.printStackTrace();
}
}
#Override
public void onError(String error) {
//show error code
}
});
}
Let me know after you try this #Abhishek

I need to display data on top of a RecyclerView after refreshing in reverse order

Recycle view load list and reached at top by mList.add(0,actor) but i want to reverse the list.
also i chnaged my code like this,
mLayoutManager.setReverseLayout(true);
mList.add(0,actor);
Here is my recycleview info, This is my recyclview api code InfoJson() here:
public class GatekeeperInfoActivity extends BaseActivity implements View.OnClickListener , MyComplaintListner {
private RecyclerView mRecyclerView;
private GateInfoAdapter mAdapter;
private RecyclerView.LayoutManager mLayoutManager;
private List<GateInfoPojo> mList;
Context ctx;
String visitor_id,id,cid;
M_Shared_Pref m_shared_pref;
ImageView back_button, img;
private MyDialog dialog;
TextView complaint,subject,msg,from_name_txt;
ImageView attach;
String from_id,from_name,from_mobile;
String id_rwa,new_id;
public static final int DISMISS_TIMEOUT = 2000;
LinearLayout ll_no_data;
int limit =0;
int limit_refresh;
static int nums;
private appconfig.EndlessRecyclerOnScrollListener scrollListener;
LinearLayoutManager linearLayoutManager;
public int overallXScrol = 0;
Button button;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.rwa_view_info);
ctx = GatekeeperInfoActivity.this;
dialog = new MyDialog(this);
m_shared_pref = new M_Shared_Pref(GatekeeperInfoActivity.this);
visitor_id = m_shared_pref.getPrefranceStringValue(App_Info.Visitor_ID);
id = m_shared_pref.getPrefranceStringValue(App_Info.Flat_User_Id);
cid = m_shared_pref.getPrefranceStringValue(App_Info.Flat_User_Id_cid);
Bundle bundle = this.getIntent().getExtras();
from_id = bundle.getString("id");
from_name = bundle.getString("name");
from_mobile = bundle.getString("mobile");
id_rwa = getIntent().getStringExtra("id_rwa");
if (from_id != null && !from_id.isEmpty() && !from_id.equals("null"))
{ new_id = from_id; }
else{ new_id = id_rwa; }
System.out.println("check:check"+from_id+":"+id_rwa);
///// using this new_id
mList = new ArrayList<GateInfoPojo>();
mRecyclerView = findViewById(R.id.my_recycler_view);
mRecyclerView.setHasFixedSize(true);
mLayoutManager = new LinearLayoutManager(this);
mRecyclerView.setLayoutManager(new LinearLayoutManager(this));
mAdapter = new GateInfoAdapter(mList, ctx);
ll_no_data = findViewById(R.id.ll_no_data);
mAdapter.setMyClickListener(this);
/* button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
limit_refresh = nums+limit;
limit = limit_refresh;
if(nums>=20){
// item_progress_bar.setVisibility(View.VISIBLE);
InfoJson();
}
}
});*/
mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
if (!recyclerView.canScrollVertically(-1)) {
// Toast.makeText(GatekeeperInfoActivity.this, "Last", Toast.LENGTH_LONG).show();
limit_refresh = nums+limit;
limit = limit_refresh;
if(nums>=20){
// item_progress_bar.setVisibility(View.VISIBLE);
InfoJson();
}
}
}
});
img = findViewById(R.id.pic);
from_name_txt = findViewById(R.id.from_name_txt);
attach = findViewById(R.id.attach);
msg = findViewById(R.id.msg);
complaint = findViewById(R.id.complaint);
subject = findViewById(R.id.subject);
back_button = findViewById(R.id.back_button);
back_button.setOnClickListener(this);
attach.setOnClickListener(this);
if(NetWorkCheck.checkConnection(GatekeeperInfoActivity.this)){
mList.clear();
InfoJson();
}
else{
TastyToast.makeText(getApplicationContext(), "Internet connection is disable", TastyToast.LENGTH_LONG, TastyToast.WARNING);
}
}
#Override
public void onClick(View v) {
switch (v.getId()){
case R.id.back_button:
finish();
break;
case R.id.attach:
if(msg.getText().toString().length()>0){
submitReply(msg.getText().toString(),new_id);
}
else{
TastyToast.makeText(getApplicationContext(), "Enter Message", TastyToast.LENGTH_LONG, TastyToast.INFO);
}
break;
}
}
public void InfoJson() {
dialog.ShowProgressDialog();
RequestQueue requestQueue = Volley.newRequestQueue(this);
StringRequest stringRequest = new StringRequest(Request.Method.POST, Constant.Base_Url+"AllChatWithUser.php?", new Response.Listener<String>() {
#Override
public void onResponse(String response) {
try {
dialog.CancelProgressDialog();
JSONObject obj = new JSONObject(response);
String error = obj.getString("error");
nums = obj.getInt("nums");
System.out.println("limit_limit_num"+nums);
if(nums>=1) {
if (error.equals("true")) {
from_name_txt.setText("GateKeeper : " + obj.getString("names"));
JSONArray tower = obj.getJSONArray("Flat");
for (int i = 0; i < tower.length(); i++) {
JSONObject jsonnew = tower.getJSONObject(i);
GateInfoPojo actor = new GateInfoPojo();
String id = jsonnew.getString("id");
String Reply_From = jsonnew.getString("reply_from");
String message = jsonnew.getString("message");
String reply_date = jsonnew.getString("send_time");
String usertype = jsonnew.getString("usertype");
actor.setId(id);
actor.setReply_from(Reply_From);
actor.setMessage(message);
actor.setSend_time(reply_date);
actor.setUsertype(usertype);
if(limit==0){
mList.add(actor);
}
else{
mList.add(0,actor);
}
mAdapter.notifyDataSetChanged();
mRecyclerView.setAdapter(mAdapter);
mRecyclerView.getLayoutManager().scrollToPosition(nums - 1);
}
}
}
else
{
mRecyclerView.setVisibility(View.GONE);
ll_no_data.setVisibility(View.VISIBLE);
// TastyToast.makeText(getApplicationContext(), obj.getString("msg"), TastyToast.LENGTH_LONG, TastyToast.ERROR);
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
VolleyLog.d(TAG, "Error: " + error.getMessage());
dialog.CancelProgressDialog();
}
}) {
#Override
protected Map<String, String> getParams() {
Map<String, String> params = new HashMap<>();
params.put("empid", new_id);
params.put("fid", id);
params.put("usertype", "FlatUser");
params.put("limit", String.valueOf(limit));
Log.e("params", String.valueOf(params));
return params;
}
};
requestQueue.add(stringRequest);
}
#Override
public void onItemClick(View v, Object bean, String feed, String rating,String comp_spinner) {
String complaint_id = ((GateInfoPojo) bean).getId();
// submitComplaintInfo(complaint_id,feed,rating,comp_spinner);
}
#Override
public void onItemClickActivity(View v, Object bean) {
String complaint_id = ((GateInfoPojo) bean).getId();
}
public void submitReply(final String msg1,final String new_id) {
dialog.ShowProgressDialog();
RequestQueue requestQueue = Volley.newRequestQueue(this);
StringRequest stringRequest = new StringRequest(Request.Method.POST, Constant.Base_Url+"ChatWithUser.php?", new Response.Listener<String>() {
#Override
public void onResponse(String response) {
try {
dialog.CancelProgressDialog();
JSONObject obj = new JSONObject(response);
String error = obj.getString("error");
if (error.equals("true"))
{
// TastyToast.makeText(getApplicationContext(), obj.getString("msg"), TastyToast.LENGTH_LONG, TastyToast.SUCCESS);
msg.setText("");
InfoJson();
mList.clear();
}
else
{
TastyToast.makeText(getApplicationContext(), obj.getString("msg"), TastyToast.LENGTH_LONG, TastyToast.ERROR);
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
VolleyLog.d(TAG, "Error: " + error.getMessage());
dialog.CancelProgressDialog();
}
}) {
#Override
protected Map<String, String> getParams() {
Map<String, String> params = new HashMap<>();
params.put("fid", id);
params.put("empid", new_id);
params.put("usertype", "FlatUser");
params.put("message", msg1);
Log.e("params", String.valueOf(params));
return params;
}
};
requestQueue.add(stringRequest);
}
}
But this is not working its add to top but not reverse the api data bottom to top.
Any help would be appreciated.

You can reverse the array list by -
Collections.reverse(mList);
After that setAdapter() or notifyDataSetChanged() according to your requirement.
public void InfoJson() {
dialog.ShowProgressDialog();
RequestQueue requestQueue = Volley.newRequestQueue(this);
StringRequest stringRequest = new StringRequest(Request.Method.POST, Constant.Base_Url+"AllChatWithUser.php?", new Response.Listener<String>() {
#Override
public void onResponse(String response) {
try {
dialog.CancelProgressDialog();
JSONObject obj = new JSONObject(response);
String error = obj.getString("error");
nums = obj.getInt("nums");
System.out.println("limit_limit_num"+nums);
if(nums>=1) {
if (error.equals("true")) {
from_name_txt.setText("GateKeeper : " + obj.getString("names"));
JSONArray tower = obj.getJSONArray("Flat");
for (int i = 0; i < tower.length(); i++) {
JSONObject jsonnew = tower.getJSONObject(i);
GateInfoPojo actor = new GateInfoPojo();
String id = jsonnew.getString("id");
String Reply_From = jsonnew.getString("reply_from");
String message = jsonnew.getString("message");
String reply_date = jsonnew.getString("send_time");
String usertype = jsonnew.getString("usertype");
actor.setId(id);
actor.setReply_from(Reply_From);
actor.setMessage(message);
actor.setSend_time(reply_date);
actor.setUsertype(usertype);
if(limit==0){
mList.add(actor);
}
else{
mList.add(0,actor);
}
}
Collections.reverse(mList);
mAdapter.notifyDataSetChanged();
mRecyclerView.setAdapter(mAdapter);
// mRecyclerView.getLayoutManager().scrollToPosition(nums - 1);
}
}
else
{
mRecyclerView.setVisibility(View.GONE);
ll_no_data.setVisibility(View.VISIBLE);
// TastyToast.makeText(getApplicationContext(), obj.getString("msg"), TastyToast.LENGTH_LONG, TastyToast.ERROR);
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
VolleyLog.d(TAG, "Error: " + error.getMessage());
dialog.CancelProgressDialog();
}
}) {
#Override
protected Map<String, String> getParams() {
Map<String, String> params = new HashMap<>();
params.put("empid", new_id);
params.put("fid", id);
params.put("usertype", "FlatUser");
params.put("limit", String.valueOf(limit));
Log.e("params", String.valueOf(params));
return params;
}
};
requestQueue.add(stringRequest);
}

Try adding the following code, both of them need to be true.
mLayoutManager.setStackFromEnd(true);
mLayoutManager.setReverseLayout(true);

From OnCreate() remove your setadapter as your list doesn't have data yet.
and in your onResponse() reverse your listdata before setting it
Collections.reverse(mList);
mAdapter = new GateInfoAdapter(mList, ctx);
mRecyclerView.setAdapter(mAdapter);

How to manage position in recycler view when scroll after notifydatasetchanged

Here is my code, I have to call method getServerResponse() for first time to get store in arraylist and when I scrolls down I have to call method getServerResponseScroll(). I got result and notify adapter but after scrolling down and up data changes position or may be not visible or get changed. I had created custom adapter for chat. Please help me how to sort out this kind of problem.
public class ChatDetailActivity extends AppCompatActivity {
String macAddress;
RecyclerView recyclerView;
Activity context;
ChatAdapter adapter;
EditText etText;
DatabaseAdapter db;
NetClient nc;
EditText edtSend;
Button btnSend;
DataPref mDataPref;
static int page = 0;
SwipeRefreshLayout mSwipeRefreshLayout;
JSONArray chatDetailListJsonArray;
String toId, channelId, toProfilePic, deviceToken, deviceOsType;
static ArrayList<ChatDetailModel> chatDetailModels = new ArrayList<ChatDetailModel>();
// User mchatUSer;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_chat_detail);
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
recyclerView = (RecyclerView) findViewById(R.id.card_recycler_view);
mSwipeRefreshLayout = (SwipeRefreshLayout) findViewById(R.id.swipeRefreshLayout);
edtSend = (EditText) findViewById(R.id.edtSend);
btnSend = (Button) findViewById(R.id.btnSend);
db = new DatabaseAdapter(this);
mDataPref = DataPref.getInstance(this);
WifiManager wifiManager = (WifiManager) getSystemService(Context.WIFI_SERVICE);
WifiInfo wInfo = wifiManager.getConnectionInfo();
macAddress = wInfo.getMacAddress();
etText = (EditText) findViewById(R.id.etText);
toId = getIntent().getStringExtra("toId");
channelId = getIntent().getStringExtra("channelId");
toProfilePic = getIntent().getStringExtra("toProfilePic");
deviceToken = getIntent().getStringExtra("deviceToken");
deviceOsType = getIntent().getStringExtra("deviceOsType");
getServerResponse(this);
connectionForSend();
btnSend.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
sendMessage();
}
});
}
void getServerResponse(final Context context){
StringRequest strReqNewsList = new StringRequest(Request.Method.POST, Constants.getChatDetailListUrl, new
Response.Listener<String>() {
#Override
public void onResponse(String response) {
System.out.println("GetNewsList Response POST " + response);
/*
if (progressDialog != null) {
if (progressDialog.isShowing())
progressDialog.dismiss();
}*/
String message = "";
try {
JSONObject jsonObjectResponse = new JSONObject(response);
String responseStatus = jsonObjectResponse.getString("status");
message = jsonObjectResponse.getString("message");
if (responseStatus.equals("true")) {
chatDetailListJsonArray = jsonObjectResponse.getJSONArray("data");
if(page==0) {
GetChat.getInstance(context).deleteAllTableData("tbl_chat_detail", channelId);
}
// JSONObject chatListJsonObject= new JSONObject(gson.toJson(chatListJsonArray));
ArrayList<ChatDetailModel> chatlistModels = new Gson()
.fromJson(chatDetailListJsonArray.toString(),
new TypeToken<List<ChatDetailModel>>() {
}.getType());
for (int i = 0; i < chatDetailListJsonArray.length(); i++) {
ChatDetailModel chatlistModel = chatlistModels.get(i);
chatlistModel.setChannel_id(channelId);
GetChat.getInstance(context).addChatDetailList(new JSONObject(new Gson().toJson(chatlistModel)));
}
JSONArray chatListJsonArray = GetChat.getInstance(ChatDetailActivity.this).getChatDetailListJsonArray(channelId);
chatDetailModels = new Gson().fromJson(chatListJsonArray.toString(), new TypeToken<List<ChatDetailModel>>() {
}.getType());
implemantation();
}
} catch (JSONException e) {
e.printStackTrace();
JSONArray chatListJsonArray = GetChat.getInstance(ChatDetailActivity.this).getChatDetailListJsonArray(channelId);
chatDetailModels = new Gson().fromJson(chatListJsonArray.toString(), new TypeToken<List<ChatDetailModel>>() {
}.getType());
implemantation();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
/* if (progressDialog != null) {
if (progressDialog.isShowing())
progressDialog.dismiss();
}*/
error.printStackTrace();
JSONArray chatListJsonArray = GetChat.getInstance(ChatDetailActivity.this).getChatDetailListJsonArray(channelId);
chatDetailModels = new Gson().fromJson(chatListJsonArray.toString(), new TypeToken<List<ChatDetailModel>>() {
}.getType());
implemantation();
// DatabaseAdapter.deleteDatabase(context);
}
}){
#Override
protected Map<String, String> getParams() {
Map<String, String> params = new HashMap<String, String>();
params.put("to_id", toId);
params.put("from_id", mDataPref.getUserId());
params.put("page",page+"");
params.put("last_sync_date_time", "");
return params;
}
#Override
public Map<String, String> getHeaders() {
Map<String, String> params = new HashMap<String, String>();
params.put("Content-Type", "application/x-www-form-urlencoded");
return params;
}
};
strReqNewsList.setRetryPolicy(new DefaultRetryPolicy(40 * 1000, 1, 1.0f));
AppController.getInstance(context).addToRequestQueue(strReqNewsList);
}
void getServerResponseScroll(final Context context) {
StringRequest strReqNewsList = new StringRequest(Request.Method.POST, Constants.getChatDetailListUrl, new
Response.Listener<String>() {
#Override
public void onResponse(String response) {
System.out.println("GetNewsList Response POST " + response);
String message = "";
try {
JSONObject jsonObjectResponse = new JSONObject(response);
String responseStatus = jsonObjectResponse.getString("status");
message = jsonObjectResponse.getString("message");
if (responseStatus.equals("true")) {
chatDetailListJsonArray = jsonObjectResponse.getJSONArray("data");
// JSONObject chatListJsonObject= new JSONObject(gson.toJson(chatListJsonArray));
ArrayList<ChatDetailModel> chatlistModels = new Gson()
.fromJson(chatDetailListJsonArray.toString(),
new TypeToken<List<ChatDetailModel>>() {
}.getType());
for (int i = 0; i < chatDetailListJsonArray.length(); i++) {
ChatDetailModel chatlistModel = chatlistModels.get(i);
chatlistModel.setChannel_id(channelId);
GetChat.getInstance(context).addChatDetailList(new JSONObject(new Gson().toJson(chatlistModel)));
}
JSONArray chatListJsonArray = GetChat.getInstance(ChatDetailActivity.this).getChatDetailListJsonArray(channelId);
// chatDetailModels.clear();
ArrayList<ChatDetailModel> chatDetailModels1 = new ArrayList<ChatDetailModel>();
chatDetailModels1 = new Gson().fromJson(chatListJsonArray.toString(), new TypeToken<List<ChatDetailModel>>() {
}.getType());
chatDetailModels.clear();
chatDetailModels.addAll(chatDetailModels1);
mSwipeRefreshLayout.setRefreshing(false);
adapter.notifyDataSetChanged();
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
/* if (progressDialog != null) {
if (progressDialog.isShowing())
progressDialog.dismiss();
}*/
error.printStackTrace();
// DatabaseAdapter.deleteDatabase(context);
}
}) {
#Override
protected Map<String, String> getParams() {
Map<String, String> params = new HashMap<String, String>();
params.put("to_id", toId);
params.put("from_id", mDataPref.getUserId());
params.put("page", page + "");
params.put("last_sync_date_time", "");
return params;
}
#Override
public Map<String, String> getHeaders() {
Map<String, String> params = new HashMap<String, String>();
params.put("Content-Type", "application/x-www-form-urlencoded");
return params;
}
};
strReqNewsList.setRetryPolicy(new DefaultRetryPolicy(40 * 1000, 1, 1.0f));
AppController.getInstance(context).addToRequestQueue(strReqNewsList);
}
void implemantation() {
RecyclerView.LayoutManager manager = new LinearLayoutManager(this.getApplicationContext());
recyclerView.setLayoutManager(manager);
adapter = new ChatAdapter(this.getApplicationContext(), chatDetailModels);
recyclerView.setAdapter(adapter);
recyclerView.scrollToPosition(chatDetailModels.size() - 1);
recyclerView.addOnItemTouchListener(new RecyclerItemClickListener(this, recyclerView, new RecyclerItemClickListener.OnItemClickListener() {
#Override
public void onItemClick(View view, int position) {
Intent i = new Intent(ChatDetailActivity.this, ProfilesDetailActivity.class);
// i.putExtra("profileId",ChatlistModel.get(position).getId());
startActivity(i);
}
#Override
public void onItemLongClick(View view, int position) {
}
}));
mSwipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
#Override
public void onRefresh() {
page++;
getServerResponseScroll(ChatDetailActivity.this);
}
});
}
// Adapter for chat
public class ChatAdapter extends RecyclerView.Adapter<ChatAdapter.ViewHolder> {
private ArrayList<ChatDetailModel> chatDetailModels;
private Context context;
public ChatAdapter(Context context, ArrayList<ChatDetailModel> chatDetailModels) {
this.context = context;
this.chatDetailModels = chatDetailModels;
}
#Override
public ChatAdapter.ViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.chat_lsit_row, viewGroup, false);
return new ViewHolder(view);
}
#Override
public void onBindViewHolder(ViewHolder viewHolder, int position) {
if (chatDetailModels.get(position).getFrom_username().equalsIgnoreCase(mDataPref.getUsername())) {
viewHolder.messageTextRight.setText(chatDetailModels.get(position).getMessage());
viewHolder.chatLeftLayout.setVisibility(View.GONE);
if (mDataPref.getProfilePicFullUrl().equals("null") || mDataPref.getProfilePicFullUrl().equals("")) {
viewHolder.fromImageView.setImageResource(R.drawable.default_profile_pic);
} else {
Picasso.with(context).load(mDataPref.getProfilePicFullUrl()).placeholder(R.drawable.default_profile_pic).transform(new CircleTransform()).resize(40, 40).into(viewHolder.fromImageView);
}
} else {
viewHolder.messageTextLeft.setText(chatDetailModels.get(position).getMessage());
viewHolder.chatRightLayout.setVisibility(View.GONE);
if (toProfilePic.equals("null") || toProfilePic.equals("")) {
viewHolder.toImageView.setImageResource(R.drawable.default_profile_pic);
} else {
Picasso.with(context).load(toProfilePic).placeholder(R.drawable.default_profile_pic).transform(new CircleTransform()).resize(40, 40).into(viewHolder.toImageView);
}
}
}
#Override
public int getItemCount() {
return chatDetailModels.size();
}
public class ViewHolder extends RecyclerView.ViewHolder {
private LinearLayout chatLeftLayout;
private ImageView toImageView;
private TextView messageTextLeft;
private LinearLayout chatRightLayout;
private TextView messageTextRight;
private ImageView fromImageView;
public ViewHolder(View view) {
super(view);
chatLeftLayout = (LinearLayout) view.findViewById(R.id.chatLeftLayout);
toImageView = (ImageView) view.findViewById(R.id.toImageView);
messageTextLeft = (TextView) view.findViewById(R.id.message_text_left);
chatRightLayout = (LinearLayout) view.findViewById(R.id.chatRightLayout);
messageTextRight = (TextView) view.findViewById(R.id.message_text_right);
fromImageView = (ImageView) view.findViewById(R.id.fromImageView);
}
}
}
}

From onSaveInstanceState documentation:
Called when the LayoutManager should save its state. This is a good time to save your
* scroll position, configuration and anything else that may be required to restore the same
* layout state if the LayoutManager is recreated.
* RecyclerView does NOT verify if the LayoutManager has changed between state save and
* restore. This will let you share information between your LayoutManagers but it is also
* your responsibility to make sure they use the same parcelable class.
To get current state of recyclerview:
private Parcelable recyclerViewState = recyclerView.getLayoutManager().onSaveInstanceState();
to restore saved instance:
recyclerView.getLayoutManager().onRestoreInstanceState(recyclerViewState);

Recycler view not rendering the data list

I'm trying to implement a recycler view in fragment using Volley library.
Data is loaded and logged successfully from the server but not displayed at all in the recycler fragment.
The request fetches the data and logs it but nothing renders in the fragment. There are no XML errors.
HitVideoFragment.java
public class HitVideoFragment extends Fragment {
private RecyclerView recyclerView;
private HitVideoAdapter adapter;
private List<HitVideo> hitVideoList = new ArrayList<HitVideo>();
public HitVideoFragment() {
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setHasOptionsMenu(true);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_hit_video, container, false);
return view;
}
#Override
public void onActivityCreated(Bundle savedInstanceState){
super.onActivityCreated(savedInstanceState);
//Initializing Views
recyclerView = (RecyclerView) this.getActivity().findViewById(R.id.hitvideo_recycler_view);
RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(this.getActivity());
recyclerView.setHasFixedSize(false);
recyclerView.setLayoutManager(layoutManager);
recyclerView.setItemAnimator(new DefaultItemAnimator());
adapter = new HitVideoAdapter(hitVideoList);
recyclerView.setAdapter(adapter);
//Calling method to get data
//Showing a progress dialog
final ProgressDialog loading = ProgressDialog.show(this.getActivity(),"Loading Data", "Please wait...",false,false);
//Creating a json array request
JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(AppConfig.URL_HIT_VIDEOS,
new Response.Listener<JSONArray>() {
#Override
public void onResponse(JSONArray response) {
//Dismissing progress dialog
loading.dismiss();
Log.d("Some tag", "onResponse: "+response.toString());
hitVideoList = new ArrayList<HitVideo>();
for(int i = 0; i<response.length(); i++) {
HitVideo hitVideo = new HitVideo();
JSONObject json = null;
try {
json = response.getJSONObject(i);
hitVideo.setTitle(json.getString("name"));
hitVideo.setUrl(json.getString("url"));
hitVideo.setUsername(json.getString("user_id"));
hitVideo.setHits(json.getInt("hits"));
} catch (JSONException e) {
e.printStackTrace();
}
hitVideoList.add(hitVideo);
}
adapter.notifyDataSetChanged();
}
},
new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
VolleyLog.d("Hit Video", "Error: " + error.getMessage());
}
}) {
#Override
public Map<String, String> getHeaders() throws AuthFailureError {
HashMap<String, String> headers = new HashMap<>();
Context _context = getActivity().getApplicationContext();
SharedPreferences pref;
String token;
if (_context != null) {
pref = _context.getSharedPreferences(Config.PREF_NAME, Config.PRIVATE_MODE);
if (pref != null) {
token = pref.getString(Config.USER_TOKEN, null);
headers.put("Authorization", "Bearer " + token);
}
}
return headers;
}
};
//Creating request queue
RequestQueue requestQueue = Volley.newRequestQueue(this.getActivity());
//Adding request to the queue
requestQueue.add(jsonArrayRequest);
}
This is not throwing any exceptions. And the model and adapters are doing their job fine. Thanks in advance.

I am probably too late to this,
But I had the same issue and I fixed it by returning the list.size() on the getItemCout() method in the Adapter class.