I have a simple URL that fetches some pics from pixabay website. with this URL: https://pixabay.com/api/?key=15507399-305bf88eb0892f7cdf58fb66b&image_type=photo&pretty=true&q=yellow+flowers.
Clicking on the link it is shown the JSON response. I want to get the "id" and "largeImageURL". but the method doesn't even execute. the Arraylist that is supposed to contain the values is always size = 0.
I have added the
<uses-permission android:name="android.permission.INTERNET"/>
I have no clue what I'm missing here
requestQueue = Volley.newRequestQueue(this);
loadImages();
//testing
String[] names = null;
for (int i = 0; i < images.size(); i++) {
names[i] = images.get(i).getId();
}
}
private void loadImages() {
String url = "https://pixabay.com/api/?key=15507399-305bf88eb0892f7cdf58fb66b&image_type=photo&pretty=true&q=yellow+flowers";
JsonObjectRequest request = new JsonObjectRequest(Request.Method.GET, url, null, new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
try {
JSONArray hits = response.getJSONArray("hits");
for (int i = 0; i < hits.length(); i++) {
JSONObject pics = hits.getJSONObject(i);
images.add(new Flowers(pics.getString("id"), pics.getString("largeImageURL")));
}
} catch (Exception e) {
e.printStackTrace();
Toast.makeText(MainActivity.this, "ha", Toast.LENGTH_SHORT).show();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Log.e("test", "Error", error);
}
});
requestQueue.add(request);
}
Your code is working except that the placement of the block of codes '//testing' is at the wrong location resulting in size = 0. It takes time for the data to come in before 'onResponse()' get triggered and stores the data in 'images'. But you are already accessing the 'images' before 'onResponse()'.
Related
I'm trying to parse json using volley but I cant receive the data. Assume that I received the data. I send that to the recycler view. But I'm not sure about using the JSONObject. Maybe there is a error I couldn't see it. And this is my json website "https://docs.spacexdata.com/#3d6e6f8a-a459-4265-84b1-e2b288a58537".
private void parseJson() {
String url = "https://docs.spacexdata.com/#d65a7f85-e0c7-41ce-b41d-9ad20a238d90";
JsonArrayRequest request = new JsonArrayRequest(Request.Method.GET, url, null, new Response.Listener<JSONArray>() {
#Override
public void onResponse(JSONArray response) {
try {
for(int i = 0; i < response.length(); i++) {
JSONObject capsuleObject = response.getJSONObject(i);
String details = capsuleObject.getString("details");
String type = capsuleObject.getString("type");
mCapsuleList.add(new Capsule("null", "null", "null", "null", 0, 0, type, details, 0));
}
mCapsuleAdapter = new CapsuleAdapter(CapsuleFragment.this.getContext(), mCapsuleList);
mRecyclerView.setAdapter(mCapsuleAdapter);
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
error.printStackTrace();
}
});
mRequestQueue.add(request);
}
There is a lot of value in json but I just want to receive "type" and "detail". It says my request is null. So how can i parse this?
The jason array request code goes like this:
JsonArrayRequest arrayRequest = new JsonArrayRequest(Request.Method.GET,url, (JSONArray) null , new Response.Listener<JSONArray>() {
#Override
public void onResponse(JSONArray response) {
try {
Log.d("Response:", String.valueOf(response.getJSONObject(0)));
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(context, "Response not recieved", Toast.LENGTH_SHORT).show();
}
});
And I've used a singleton instance of a request queue, to fetch the data,
AppController.getInstance(context.getApplicationContext()).addToRequestQueue(arrayRequest);
I'm using an api service that supplies a bunch of questions (The api generates a url, which returns a collection of JSON Objects, An Array (Just try and Open the url link, the json array will be seen)
But when I run the app, the request is not even getting a response,the progam flow is going into the error listner block.
Can someone explain this behaviour? Is it because the JSON array supplied by the url, has nested arrays? Why?
I tried reading and anlyzing other questions here, which might have the same issue, But i found nothing.
You want to just change JsonArrayRequest to JsonObjectRequest:
Please copy and paste below code:
JsonObjectRequest jsonObjReq = new JsonObjectRequest(Request.Method.GET,
url, null,
new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
Log.d("TAG", response.toString());
try {
JSONArray jsonArray = response.getJSONArray("results");
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject jsonObject = jsonArray.getJSONObject(i);
String category = jsonObject.getString("category");
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
VolleyLog.d("TAG", "Error: " + error.getMessage());
// hide the progress dialog
}
});
AppController.getInstance().addToRequestQueue(jsonObjReq, "TAG");
Follow this link for learn other request: Androidhive
I am working on an android app.
I want to retrieve json data into an ArrayList of my data model called Expert.
Here is the code on the onCreate() method
mExpertsList = new ArrayList<Expert>();
loadData();
Log.v("RESPONSE", Integer.toString(mExpertsList.size()));
Here is the code in the function retrieving json data.
private void loadData(){
RequestQueue queue = Volley.newRequestQueue(MainActivity.this);
JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.GET, "http://microblogging.wingnity.com/JSONParsingTutorial/jsonActors",
null, new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
try {
JSONArray jarray = response.getJSONArray("actors");
for (int i = 0; i < jarray.length(); i++) {
JSONObject object = jarray.getJSONObject(i);
Expert expert = new Expert();
expert.setImageUrl(object.getString("image"));
expert.setName(object.getString("name"));
expert.setTopic(object.getString("country"));
expert.setRating(random.nextFloat() * ((maxRating - minRating) + minRating));
expert.setDescription(object.getString("description"));
mExpertsList.add(expert);
}
}
catch(JSONException e){
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
}
});
queue.add(jsonObjectRequest);
}
Inside loadData() method the mExpertsList shows size of 6 at end of for loop. Checked this using log messages.
But a Log statement immediately after loadData() shows that mExpertsList has size of zero.
What am I missing here?
JsonObjectRequest is an Asynchronous request so your list will be update on other thread . And you logged the size synchronously so it will print 0 always .
Access the List inside onResponse(JSONObject response);
JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.GET, "http://microblogging.wingnity.com/JSONParsingTutorial/jsonActors",
null, new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
try {
JSONArray jarray = response.getJSONArray("actors");
for (int i = 0; i < jarray.length(); i++) {
JSONObject object = jarray.getJSONObject(i);
Expert expert = new Expert();
expert.setImageUrl(object.getString("image"));
expert.setName(object.getString("name"));
expert.setTopic(object.getString("country"));
expert.setRating(random.nextFloat() * ((maxRating - minRating) + minRating));
expert.setDescription(object.getString("description"));
mExpertsList.add(expert);
}
Log.v("RESPONSE", mExpertsList.size());
}
catch(JSONException e){
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
}
});
mExpertsList = new ArrayList<Expert>(); // You are initializing your list with size 0
loadData(); // Calling the API which will run in background
So whenever you are calling
Log.v("RESPONSE", Integer.toString(mExpertsList.size()));just after loadData() method your mExpertsList is still of size 0.
Size will change only after you get your API response.
This is an Asynchronous operation, Volley will not wait for your response and execute your next code.
If you want to print Arraylist size then print it just after for loop,
JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.GET, "http://microblogging.wingnity.com/JSONParsingTutorial/jsonActors",
null, new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
try {
JSONArray jarray = response.getJSONArray("actors");
for (int i = 0; i < jarray.length(); i++) {
JSONObject object = jarray.getJSONObject(i);
Expert expert = new Expert();
expert.setImageUrl(object.getString("image"));
expert.setName(object.getString("name"));
expert.setTopic(object.getString("country"));
expert.setRating(random.nextFloat() * ((maxRating - minRating) + minRating));
expert.setDescription(object.getString("description"));
mExpertsList.add(expert);
}
Log.v("RESPONSE", mExpertsList.size());
}
catch(JSONException e){
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
}
});
It will print the exxact size of your list.
It looks like you are making some kind of asynchronous call when you call loadData():
mExpertsList = new ArrayList<Expert>();
loadData();
Log.v("RESPONSE", Integer.toString(mExpertsList.size()));
When you check the size, it is possible that onResponse(), the handler for the web call, has not yet been called. If so, then the size would still appear to be zero.
You should only be relying on the contents of mExpertsList being there if onResponse has been successfully called with actual content.
Do this change in part 1:
mExpertsList = new ArrayList<Expert>();
loadData();
//Log.v("RESPONSE", Integer.toString(mExpertsList.size()));----Comment it out
Change in part 2:
private void loadData(){
RequestQueue queue = Volley.newRequestQueue(MainActivity.this);
JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.GET, "http://microblogging.wingnity.com/JSONParsingTutorial/jsonActors",
null, new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
try {
JSONArray jarray = response.getJSONArray("actors");
for (int i = 0; i < jarray.length(); i++) {
JSONObject object = jarray.getJSONObject(i);
Expert expert = new Expert();
expert.setImageUrl(object.getString("image"));
expert.setName(object.getString("name"));
expert.setTopic(object.getString("country"));
expert.setRating(random.nextFloat() * ((maxRating - minRating) + minRating));
expert.setDescription(object.getString("description"));
mExpertsList.add(expert);
Log.v("RESPONSE", Integer.toString(mExpertsList.size())); //-----New ADDED
}
}
catch(JSONException e){
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
}
});
queue.add(jsonObjectRequest);
}
I Know at first glance it's known mistake made by beginners but:
My standard response looks like this:
public ArrayList<Beer> jsonResponse(){
beerList.clear();
requestQueue = Volley.newRequestQueue(this);
JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(
Request.Method.GET,
Constants.BASE_API_URL + Constants.BEER_LIST_URL_ENDPOINT,
null,
new Response.Listener<JSONArray>() {
#Override
public void onResponse(JSONArray response) {
try {
for (int i = 0; i < response.length(); i++) {
JSONObject beerJsonObject = response.getJSONObject(i);
System.out.println(response.toString());
Beer beer = new Beer();
if (beerJsonObject.has("yeast")) {
beer.setYeast(beerJsonObject.getString("yeast"));
}
beer.setName(beerJsonObject.getString("name"));
beer.setIbu(beerJsonObject.getString("ibu"));
beer.setAlc(beerJsonObject.getString("abv"));
beer.setImgUrl(beerJsonObject.getString("image_url"));
beer.setId(beerJsonObject.getString("id"));
beer.setDescription(beerJsonObject.getString("description"));
beer.setFoodPairing(beerJsonObject.getString("food_pairing"));
beer.setFirstBrewed(beerJsonObject.getString("first_brewed"));
System.out.println(beer.getName()+" "+beer.getIbu()+" "+beer.getImgUrl());
beerList.add(beer);
}
beerRecyclerViewAdapter.notifyDataSetChanged();
} catch (JSONException e) {
e.printStackTrace();
}
}
},
new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(MainActivity.this, "Error", Toast.LENGTH_SHORT).show();
}
}
);
// Add JsonArrayRequest to the RequestQueue
requestQueue.add(jsonArrayRequest);
return beerList;
}
Everything works except "yeast" item:
if (beerJsonObject.has("yeast")) {
beer.setYeast(beerJsonObject.getString("yeast"));
}
without that if statement I've got standard json err. response no value for "yeast", I thought maybe not every object in response has this value and added that. But that doesn't helped, I still can't get that value, like it wouldn't exist in array, but it's not true, even in System.out.println(response.toString()) I can see a lot of "yeast" .
Here is example response from API I'm working with: https://api.punkapi.com/v2/beers
yeast is under ingredients
so should be:
if (beerJsonObject.has("ingredients")) {
JSONObject ingredients = beerJsonObject.getJSONObject("ingredients");
if (ingredients.has("yeast")) {
beer.setYeast(ingredients.getString("yeast"));
}
}
I have json api with many objects in it, I want store the data in the Map after giving a key. Then I want use that Map list later. below is the way i want do it.
Map<Integer, Integer> maplist; /// globle variable
//// inside response method inside the for loop
maplist = new HasMap<>();
maplist.put(10, 1);
//////.....
........
You can do something like this. below is the sample code
public void getQtyReserved() {
JsonObjectRequest request_json = new JsonObjectRequest(Request.Method.GET, cart_url + name, null,
new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
listMap = new HashMap<Integer, Integer>();
try {
JSONArray ja_data = response.getJSONArray("list");
int length = ja_data.length();
for (int i = 0; i < length; i++) {
JSONObject jsonobject = ja_data.getJSONObject(i);
int quantity_reserved = jsonobject.getInt("quantity_reserved");
int inventory_id = jsonobject.getInt("inventory_id");
listMap.put(inventory_id, quantity_reserved);
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
VolleyLog.e("Error: ", error.getMessage());
Toast.makeText(getApplicationContext(), "its empty", Toast.LENGTH_LONG).show();
}
});
MySingleton.mySingletonInstance(getApplicationContext()).addToRequestque(request_json);
}