Why the arrayList always empty under Volley response result loop? - android

The carList is declared as a public variable in the class, and the log shows that values are added in the array, yet when I call the list is empty, how to solve it with Volley response?
public void onResponse(JSONObject response) {
try {
JSONArray resArray = response.getJSONArray("result");
for(int i=0;i<resArray.length();i++) {
JSONObject car = resArray.getJSONObject(i);
String id = car.getString("id");
String brand = car.getString("brand");
String created = car.getString("created");
carList.add(new CarListItem(brand, plate_number));
Log.d(TAG, "ADDED___: " +brand + " " + plate_number);
}
Thanks

#Benp
You right, the solution is to add the recycler adapter within the onResponse body as here:
public void onResponse(JSONObject response) {
try {
JSONArray resArray = response.getJSONArray("result");
for (int i = 0; i < resArray.length(); i++) {
JSONObject car = resArray.getJSONObject(i);
String id = car.getString("id");
String brand = car.getString("brand");
String created = car.getString("created");
carList.add(new CarListItem(car_id, brand, plateNumber, color));
}
} catch (JSONException e) {
e.printStackTrace();
}
if (carList.size() > 0) {
mAdapter = new RecyclerAdapterCarsList(carList);
buildRecyclerView();
}
}
It was simple, need a tiny clue to fix it ;)
Thanks for helping

Related

How to get Retrofit 2 error from array body

My current response is
{"response":"validation error","status":"failure","code":400,"errors":["You can not add multiple items with different categories"]}
My current code is :
String errorBody = response.errorBody().string();
JSONObject jsonObject = new JSONObject(errorBody.trim());
jsonObject = jsonObject.getJSONObject("errors");
Iterator<String> keys = jsonObject.keys();
String errors = "";
while (keys.hasNext()) {
String key = keys.next();
JSONArray arr = jsonObject.getJSONArray(key);
for (int i = 0; i < arr.length(); i++) {
errors += key + " : " + arr.getString(i) + "\n";
}
}
I am trying to get the error code to see if it matches specific keywords to handle the response
i think your current code its not to good,better way for u is:
create modelClass for your json output and in retrofit calls write:
if (model.status=='failure' || model.code==400){
print(response.message) // or something like this
}
You can look through the following code snippet
call.enqueue(new Callback<PagedResponse<NotificationModel>>() {
#RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN)
#Override
public void onResponse(Call<PagedResponse<NotificationModel>> call, Response<PagedResponse<NotificationModel>> response) {
if (response.isSuccessful()) {
if (response.code() == 200) {
try {
PagedResponse<NotificationModel> notifications = (PagedResponse<NotificationModel>) response.body();
tvRecordsCount.setText("Total "+response.body().getTotal()+" Notifications ");
showNotification(notifications);
} catch (Exception e){
e.printStackTrace();
}
} else {
showToast(getApplicationContext(), "Server Error");
}
}
}
#Override
public void onFailure(Call<PagedResponse<NotificationModel>> call, Throwable t) {
showToast(getApplicationContext(), t.getMessage());
}
});
I managed to get it working with this code:
String errors = "";
String errorBody = response.errorBody().string();
JsonParser parser = new JsonParser();
JsonObject rootObj = parser.parse(errorBody.trim()).getAsJsonObject();
JsonArray errorArray = rootObj.getAsJsonArray("errors");
for (JsonElement pa : errorArray) {
errors = pa.getAsString();
}

How to parse multiple Json values in Android?

I tried doing it multiple times using Volley library.
Link for JSON values: here
My android code to parse the values: here
public class GetUSGSjson extends AppCompatActivity
{
GridView jsonGridView;
ListView jsonListView;
Button jsonGetBtn;
RequestQueue USGSrequestqueue;
String USGSurl = "https://earthquake.usgs.gov/fdsnws/event/1/query?format=geojson&starttime=2016-01-01&endtime=2016-01-31&minmag=6&limit=10";
ArrayList<String> mArrayList;
ArrayList<String>FK;
JsonObjectRequest USGSjsonObjectReq;
JSONObject _properties_;
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.json_data);
jsonGridView = (GridView) findViewById(R.id.jsonGridView);
jsonGetBtn = (Button) findViewById(R.id.jsonGetBtn);
USGSrequestqueue = Volley.newRequestQueue(this);
mArrayList = new ArrayList<>();
FK = new ArrayList<>();
jsonGridView.setVisibility(View.GONE);
}
OnCllick of the button
public void USGSgetData(View view)
{
jsonGridView.setVisibility(View.VISIBLE);
USGSjsonObjectReq = new JsonObjectRequest(Request.Method.GET,USGSurl,null,
new Response.Listener<JSONObject>()
{
#Override
public void onResponse(JSONObject response)
{
try {
JSONObject _features_ = response.getJSONObject("features");
JSONArray _f_ = response.getJSONArray("features");
for (int x = 0; x < _f_.length(); x++)
{
JSONObject currentFeature = _f_.getJSONObject(x);
_properties_ = currentFeature.getJSONObject("properties"); //JsonObject
double mag = _properties_.getDouble("mag");
long time = _properties_.getLong("time");
String place = _properties_.getString("place");
mArrayList.add(String.valueOf(mag));
mArrayList.add(String.valueOf(time));
mArrayList.add(place);
ArrayAdapter VarrayAdapter = new ArrayAdapter<>(GetUSGSjson.this
,android.R.layout.simple_list_item_1, mArrayList);
jsonGridView.setAdapter(VarrayAdapter);
} catch (JSONException e)
{
e.printStackTrace();
Toast.makeText(GetUSGSjson.this, "Exception: "+e.getMessage(), Toast.LENGTH_LONG).show();
}
}
},
new Response.ErrorListener()
{
#Override
public void onErrorResponse(VolleyError error)
{
Toast.makeText(GetUSGSjson.this, "onErrorResponse: "+error.getMessage(), Toast.LENGTH_LONG).show();
}
}
);
USGSrequestqueue.add(USGSjsonObjectReq);
}
}
Try this,
try {
JSONArray arr_features=response.getJSONArray("features");
for(int i=0;i<arr_features.length();i++)
{
JSONObject obj=arr_features.getJSONObject(i);
String type=obj.getString("type");
JSONObject obj_properties=obj.getJSONObject("properties");
String mag=obj_properties.getString("mag");
String place=obj_properties.getString("place");
String time=obj_properties.getString("time");
String updated=obj_properties.getString("updated");
}
} catch (JSONException e) {
e.printStackTrace();
}
I found this way to solve my own problem
Remember that the "mag" is in double form "place" & "type" are in String form & "time" is a Unix time it's in long form.
try {
JSONArray _f_ = response.getJSONArray("features");
for (int x = 0; x < _f_.length(); x++)
{
JSONObject currentFeature = _f_.getJSONObject(x);
_properties_ = currentFeature.getJSONObject("properties"); //JsonObject
double mag = _properties_.getDouble("mag");
long time = _properties_.getLong("time");
String place = _properties_.getString("place");
String type = _properties_.getString("type");
// To add this on to ArrayList.
mArrayList.add("Place: "+place+"\n");
mArrayList.add("\nMagnitude: " + String.valueOf(mag)+"\n");
mArrayList.add("\nTime: " + String.valueOf(newTime)+"\n");
mArrayList.add("\nType: " + type+"\n");
}

Volley Object request Returning 0

I Have a Remote Database that contains 6 rows.
Here's my code, I put it in List so that i can get the size,
But it's always returning 0.
public List<Comments> getComments() {
final List<Comments> commentsData = new ArrayList<>();
JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.POST,
showUrl, new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
try {
JSONArray jsonArray = response.getJSONArray("poi");
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject jsonObject = jsonArray.getJSONObject(i);
Comments current = new Comments();
current.image = "drawable://" + R.drawable.juandirection_placeholder;
current.title = jsonObject.getString("title");
current.comment = jsonObject.getString("comment");
current.date = jsonObject.getString("date");
current.rating = Integer.parseInt(jsonObject.getString("rating"));
commentsData.add(current);
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
}
});
VolleyHelper.getInstance(getApplicationContext()).addToRequestQueue(jsonObjectRequest);
return commentsData;
}
I need the size for some use.
Why is it always returning zero?
I even tried adding a counter++ inside for loop.
But when i get the value of the counter its still zero.
JsonObjectRequest run on a background thread. That's why you getting the list size 0. you must work into the public void onResponse(JSONObject response) {} function .
Exmp.
#Override
public void onResponse(JSONObject response) {
try {
JSONArray jsonArray = response.getJSONArray("poi");
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject jsonObject = jsonArray.getJSONObject(i);
Comments current = new Comments();
current.image = "drawable://" + R.drawable.juandirection_placeholder;
current.title = jsonObject.getString("title");
current.comment = jsonObject.getString("comment");
current.date = jsonObject.getString("date");
current.rating = Integer.parseInt(jsonObject.getString("rating"));
commentsData.add(current);
}
// **you may call function and pass the list value to update your ui component. you will get the real size of list here.**
} catch (JSONException e) {
e.printStackTrace();
}
}

Android json processing

I'm reading json and it works fine.
But it's failed to add resulting String into the ArrayList.
Any ideas why ?
Here is the code.
StuffPics class (updated):
public class StuffPics {
private String imageUrl;
public StuffPics() {
}
public String getImageUrl() {
return imageUrl;
}
public String setImageUrl(String imageUrl) {
return this.imageUrl;
}
#Override
public String toString() {
return "StuffPics = " + this.imageUrl;
}
}
Activity (updated):
private ArrayList<StuffPics> mylist;
...
protected void onPostExecute(String result) {
try{
String url="http://www.test.com";
JSONArray jsonarray = new JSONArray(result);
int lengthJsonArr = jsonarray.length();
for (int i = 0; i < lengthJsonArr; i++)
{
//build url
JSONObject jsonChildNode = jsonarray.getJSONObject(i);
String autcElement = jsonChildNode.optString("picUrl").toString();
String img= url + autcElement;
System.out.println("imageUrl"+img);
//create object and add it to the list
StuffPics pic = new StuffPics();
pic.getImageUrl();
System.out.print("PIC"+pic);
mylist.add(pic);
}
}
catch (Exception e) {
e.printStackTrace();
}
}
So, the first System.out shows strings, as they should be. Means json was read the right way.
But the second System.out shows nothing. Means I can't add strings into StuffPics pic. As the result ArrayList mylist is empty as well.
What am I doing wrong ?
Well pic is a custom object StuffPics .
You will need to override toString() in order to see something
for example:
#Override
public String toString() {
return "StuffPics = " + this.imageUrl;
}
also make sure mylist is initialized and you can adjust your code like this:
try{
String url="http://www.test.com";
JSONArray jsonarray = new JSONArray(result);
int lengthJsonArr = jsonarray.length();
for (int i = 0; i < lengthJsonArr; i++)
{
//build url
JSONObject jsonChildNode = jsonarray.getJSONObject(i);
String autcElement = jsonChildNode.optString("picUrl").toString();
String img= url + autcElement;
System.out.println("imageUrl"+img);
//create object and add it to the list
StuffPics pic = new StuffPics();
pic.setImageUrl(img);
System.out.print("PIC"+pic.toString());
mylist.add(pic);
}
}
catch (Exception e) {
e.printStackTrace();
}
You can use Gson
to view your custom objects.son is a Java library that can be used to convert Java Objects into their JSON representation.
simply convert your object to a json using:
String json = new Gson().Json(pic);
and print it using logs.
Replace this line:
System.out.print("PIC"+pic);
with that:
System.out.print("PIC"+pic.getImageUrl());
Your list is not empty, you are only not able to see the URL you added.

storing json parsed values as string in array

I've got a json object, which is being collected into a function as string.
It contains array
{"officer_name":"V. M. ARORA"}{"officer_name":"Dr. C. P.
REDDY"}{"officer_name":"ARTI CHOWDHARY"}{"officer_name":"JAGDISH
SINGH"}
and here is the android code
public void func4(View view)throws Exception
{
AsyncHttpClient client = new AsyncHttpClient();
RequestParams rp = new RequestParams();
rp.put("pLat", "SELECT officer_name FROM iwmp_officer");
client.post("http://10.0.2.2/conc5.php", rp, new AsyncHttpResponseHandler() {
public final void onSuccess(String response) {
// handle your response here
ArrayList<String> User_List = new ArrayList<String>();
try {
/* here I need output in an array,
and only names not the "officer_name" */
} catch (Exception e) {
tx.setText((CharSequence) e);
}
//tx.setText(User_List.get(1));
}
#Override
public void onFailure(Throwable e, String response) {
// something went wrong
tx.setText(response);
}
});
}
The output I've shown above is in String, need to get it in array. Please help!
If the output you got is something like this.
String outputJson=[{"officer_name":"V. M. ARORA"}{"officer_name":"Dr. C. P. REDDY"}{"officer_name":"ARTI CHOWDHARY"}{"officer_name":"JAGDISH SINGH"}]
Then its a JSON Array.
You can parse it as
JsonArray array=new JsonArray(outputJson);
Then loop this json array using
for(JsonObject jsonObj in array){
String officerName=[jsonObj getString("officer_name");
}
You can use something like above The mentioned code is not correct syntactically but yes conceptually correct. You can go ahead with this.
List < String > ls = new ArrayList< String >();
JSONArray array = new JSONArray( response );
for (int i = 0; i < array.length() ; i++ ) {
JSONObject obj = array.getJSONObject(Integer.toString(i));
ls.add(obj.getString("officer_name"));
}
This would work
try {
JSONArray array= new JSONArray(response);
//array = new JSONArray(response);
for (int i = 0; i < array.length(); i++) {
//JSONObject obj = response.getJSONArray(i);
JSONObject jsonLineItem = (JSONObject) array.getJSONObject(i);
String name_fd = jsonLineItem.getString("officer_name");
User_List.add(jsonLineItem.getString("officer_name"));
Log.d("JSONArray", name_fd+" " +name_fd);
}
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
tx.setText( e.toString());
}

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