Develop Reference

my API does not show me anything and without error?

I'm working on a web service application, I display the data in a listview
At the beginning everything works but when I changed my api nothing is displayed and no error appears , I did not find the problem please !! how can I display my data !!
it's the part of the code !!
private class GetHttpResponse extends AsyncTask<String, Void,
ArrayList<subjects>>
{
public Context context;
String ResultHolder;
public GetHttpResponse(Context context)
{
this.context = context;
}
#Override
protected void onPreExecute()
{
super.onPreExecute();
}
#Override
protected ArrayList<subjects> doInBackground(String... arg0)
{
HttpServicesClass httpServiceObject = new HttpServicesClass(arg0[0]);
ArrayList<subjects> subjectsList = new ArrayList<subjects>();
try
{
httpServiceObject.ExecutePostRequest();
if(httpServiceObject.getResponseCode() == 200)
{
ResultHolder = httpServiceObject.getResponse();
if(ResultHolder != null)
{
JSONArray jsonArray = null;
try {
jsonArray = new JSONArray(ResultHolder);
JSONObject jsonObject;
subjects subjects;
for(int i=0; i<jsonArray.length(); i++)
{
subjects = new subjects();
jsonObject = jsonArray.getJSONObject(i);
if(valueInteger == jsonObject.getInt("tache_id") )
{
// subjects.nom=jsonObject.getString("nom");
subjects.SubjectName =
jsonObject.getDouble("tarif");
subjects.technicien_id =
jsonObject.getString("technicien_id");
subjectsList.add(subjects);
}}}
catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}}}}
catch (Exception e)
{
// TODO Auto-generated catch block
Log.e("Tech", "exception", e);
}
return subjectsList;
}
and this is my json
[
{
"tache_id": "2",
"technicien_id": "2",
"tarif": "100"
},
{
"tache_id": "3",
"technicien_id": "3",
"tarif": "200"
}]

Most probably there is an exception but your are catching it.Start removing your catch statements one by one until you find the error or put log messages in the catch statements.

When you changed your Api your response structure may be changed.So, Ensure the following steps:
Step1 - Save the response of your Api
Step2 - Your Api's JSON response contain Arrays and Objects.Write your code according to the response.

org.json.JSON.typeMismatch(JSON.java:111)

I am getting a org.json.JSON.typeMismatch(JSON.java:111) error while trying to create a JSON array. The received data looks like this:
{
"result":[
{
"#type":"d",
"#rid":"#-2:0",
"#version":0,
"a_adres":"kepez merkez geliyor herkez",
"takipkodu":"464664",
"agirlik":50
},
{
"#type":"d",
"#rid":"#-2:1",
"#version":0,
"a_adres":"merkez mahallesi 4 sok",
"takipkodu":"sd4fs654f64",
"agirlik":60
}
]
}
Code:
protected String doInBackground(String... urls) {
try {
String getResponse = get("http://178.18.206.128:2480/command/nakliye/sql/select a_adres,takipkodu,agirlik from yukilan");
return getResponse;
} catch (Exception e) {
this.exception = e;
return null;
}
}
protected void onPostExecute(String getResponse) {
ListView liste=(ListView)findViewById(R.id.list_view);
try {
JSONArray yukilanarray = new JSONArray(getResponse);
List<Yukilan> yukilanlar = new ArrayList<>();
//Populate the EmployeeDetails list from response
for (int i = 0; i<yukilanarray.length();i++){
Yukilan yeniilan = new Yukilan();
JSONObject yukilanobject = yukilanarray.getJSONObject(i);
yeniilan.setAdres(yukilanobject.getString(KEY_ADRES));
yeniilan.setAgirlik(yukilanobject.getString(KEY_AGIRLIK));
yeniilan.setTakip_kod(yukilanobject.getString(KEY_TAKIPKODU));
yukilanlar.add(yeniilan);
}
//Create an adapter with the EmployeeDetails List and set it to the LstView
yukilanadapter = new Yukilanadapter(yukilanlar,getApplicationContext());
liste.setAdapter(yukilanadapter);
} catch (JSONException e) {
e.printStackTrace();
}
// System.out.println(getResponse);
}
Please help.

I think you made a mistake in reading the json. the first element would be a JSONObject not a JSONArray.Below is the revised code.
protected String doInBackground(String... urls) {
try {
String getResponse = get("http://178.18.206.128:2480/command/nakliye/sql/select a_adres,takipkodu,agirlik from yukilan");
return getResponse;
} catch (Exception e) {
this.exception = e;
return null;
}
}
protected void onPostExecute(String getResponse) {
ListView liste=(ListView)findViewById(R.id.list_view);
try {
JSONObject jsonObject = new JSONObject(getResponse);
JSONArray yukilanarray = jsonObject.getJSONArray("result");
List<Yukilan> yukilanlar = new ArrayList<>();
//Populate the EmployeeDetails list from response
for (int i = 0; i<yukilanarray.length();i++){
Yukilan yeniilan = new Yukilan();
JSONObject yukilanobject = yukilanarray.getJSONObject(i);
yeniilan.setAdres(yukilanobject.getString(KEY_ADRES));
yeniilan.setAgirlik(yukilanobject.getString(KEY_AGIRLIK));
yeniilan.setTakip_kod(yukilanobject.getString(KEY_TAKIPKODU));
yukilanlar.add(yeniilan);
}
//Create an adapter with the EmployeeDetails List and set it to the LstView
yukilanadapter = new Yukilanadapter(yukilanlar,getApplicationContext());
liste.setAdapter(yukilanadapter);
} catch (JSONException e) {
e.printStackTrace();
}
// System.out.println(getResponse);
}

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() );
}
})

Showing ProgressBar on parsing and downloading json result

In my App I am hitting a service which can have no result to n number of results(basically some barcodes). As of now I am using default circular progressbar when json is parsed and result is being saved in local DB(using sqlite). But if the json has large number of data it sometimes takes 30-45 min to parse and simultaneously saving that data in DB, which makes the interface unresponsive for that period of time and that makes user think the app has broken/hanged. For this problem I want to show a progressbar with the percentage stating how much data is parsed and saved so that user get to know the App is still working and not dead. I took help from this link but couldn't find how to achieve. Here's my Asynctask,
class BackGroundTasks extends AsyncTask<String, String, Void> {
private String operation, itemRef;
private ArrayList<Model_BarcodeDetail> changedBarcodeList, barcodeList;
private ArrayList<String> changeRefList;
String page;
public BackGroundTasks(String operation, String itemRef, String page) {
this.operation = operation;
this.itemRef = itemRef;
this.page = page;
}
#Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
if (dialog == null) {
dialog = ProgressDialog.show(mActivity, null,
"Please wait ...", true);
}
}
#Override
protected Void doInBackground(String... params) {
// TODO Auto-generated method stub
try{
if (!connection.HaveNetworkConnection()) {
dialog.dismiss();
connection.showToast(screenSize, "No Internet Connection.");
return null;
}
if (operation.equalsIgnoreCase("DownloadChangeItemRef")) {
changeRefList = DownloadChangeItemRef(params[1]);
if (changeRefList != null && !changeRefList.isEmpty()) {
RefList1.addAll(changeRefList);
}
}
if ((changeRefList != null && changeRefList.size() >0)) {
setUpdatedBarcodes(changedBarcodeList);
}
}
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
#SuppressLint("SimpleDateFormat")
#Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
}
}
ArrayList<String> DownloadChangeItemRef(String api_token) {
ArrayList<String> changedRefList = null;
HttpClient httpClient = new DefaultHttpClient();
HttpPost postRequest = new HttpPost(thoth_url + "/" + todaysDate
+ "?&return=json");
String url = thoth_url + "/" + todaysDate + "?&return=json";
String result = "";
try {
changedRefList = new ArrayList<String>();
ResponseHandler<String> responseHandler = new BasicResponseHandler();
result = httpClient.execute(postRequest, responseHandler);
JSONObject jsonObj = new JSONObject(result);
JSONArray jsonarray = jsonObj.getJSONArray("changes");
if (jsonarray.length() == 0) {
return null;
}
for (int i = 0; i < jsonarray.length(); i++) {
JSONObject obj = jsonarray.getJSONObject(i);
changedRefList.add(obj.getString("ref"));
}
} catch (IllegalStateException e) {
// TODO Auto-generated catch block
// when there is no thoth url
Log.i("inclient: ", e.getMessage());
return null;
} catch (Exception e) {
// when there are no itemref
return null;
}
return changedRefList;
}
private boolean setUpdatedBarcodes(
final ArrayList<Model_BarcodeDetail> changedBarcodeList2) {
try {
BarcodeDatabase barcodeDatabase = new BarcodeDatabase(mActivity);
barcodeDatabase.open();
for (Model_BarcodeDetail model : changedBarcodeList2) {
barcodeDatabase.updateEntry(model, userId);
}
n++;
barcodeDatabase.close();
if (RefList1.equals(RefList)) {
if (dialog != null) {
dialog.dismiss();
}
connection.showToast(screenSize, "Barcodes updated successfully");
}
} catch (Exception e) {
Log.i("Exception caught in: ", "setDownloadedBarcodes method");
e.printStackTrace();
return false;
}
return true;
}

AsyncTask: doInbackground() not called with executeOnExecutor and execute

The code below tested on LG G3 and it worked fine. However when I tested it on a Samsung Galaxy S3/S2 doInBackground() is not called for some reason.
Code to check api:
public void startBlat(String tosearch) {
AsynctaskMovie asynctaskMovie = new AsynctaskMovie();
if (Build.VERSION.SDK_INT>=Build.VERSION_CODES.HONEYCOMB) {
asynctaskMovie.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR,tosearch);
}
else {
asynctaskMovie.execute(tosearch);
}
The Asynctask code:
class AsynctaskMovie extends AsyncTask<String, String, ArrayList<Movie>> {
JSONParser jsonParser = new JSONParser();
private static final String SEARCH_URL = "http://www.omdbapi.com/?";
#Override
protected void onPreExecute() {
super.onPreExecute();
movieArrayList = new ArrayList();
Log.i(getActivity().getCallingPackage(), "onPreExecute");
}
#Override
protected ArrayList<Movie> doInBackground(String... args) {
Log.i(getActivity().getCallingPackage(),"doInBackground");
HashMap<String, String> params = new HashMap<>();
params.put("s", args[0]);
params.put("r", "json");
JSONObject json = jsonParser.makeHttpRequest(SEARCH_URL, "GET", params);
Log.i(getActivity().getCallingPackage(), json.toString());
if (json != null) {
try {
if (json.getString("Response").equals("False")) {
return movieArrayList;
}
} catch (JSONException e) {
}
try {
JSONArray jsonArray = json.getJSONArray("Search");
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject jsonObject = (JSONObject) jsonArray.get(i);
String movieid = jsonObject.getString(App.getInstance().IMDBimdbID);
if (!movieid.equals("null")) {
Movie movie = new Movie(movieid);
movieArrayList.add(movie);
}
}
jsonArray = new JSONArray();
for (Movie movie : movieArrayList) {
params = new HashMap<>();
params.put("i", movie.getMovieid());
params.put("plot", "short");
params.put("r", "json");
JSONObject jsongetfullinfo = jsonParser.makeHttpRequest(SEARCH_URL, "GET", params);
if (jsongetfullinfo != null) {
jsonArray.put(jsongetfullinfo);
Log.i("", jsongetfullinfo.toString());
}
}
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject jObject = jsonArray.getJSONObject(i);
movieArrayList.get(i).updateFromIMDB(jObject);
}
for (Movie movie : movieArrayList) {
movie.setMovieposter(LoadFromUrl(movie.getPosterURL()));
}
return movieArrayList;
} catch (JSONException e) {
e.printStackTrace();
}
}
return movieArrayList;
}
#Override
protected void onPostExecute(ArrayList<Movie> movieArrayList) {
Log.i("ronen", "list size: " + movieArrayList.size());
if (movieArrayList.size() > 0) {
listView.setAdapter(new MovieAdapter(getActivity(), movieArrayList));
listView.setVisibility(View.VISIBLE);
} else {
Toast.makeText(getActivity().getApplicationContext(), "No found", Toast.LENGTH_SHORT).show();
}
}
private Bitmap LoadFromUrl(String theurl) {
URL url = null;
Bitmap bmp = null;
try {
url = new URL(theurl);
bmp = BitmapFactory.decodeStream(url.openConnection().getInputStream());
} catch (IOException e) {
}
return bmp;
}
}
I have no idea what could solve this problem.
Following the answers I read here it seems that the code should work, but not so.

Can't see anything suspicious.
I'd recommend running a very simple AsyncTask on a very simple app, make sure it works (if not, maybe it something to do with the phone, so try on an emulator to be sure)
Then change it step by step to resemble your code, and you'll see where the bug is.
G'Luck!