Good morning! I've been a lot of days searching for an answer similar to this but I couldn't find it, so here I am.
In Android Studio, I've did a function which has a jsonArrayRequest request, which looks like this:
private String requestCoursesInfo() {
RequestQueue requestQueue = Volley.newRequestQueue(this.context);
JsonArrayRequest jsonArrayRequest= new JsonArrayRequest(
Request.Method.GET,
COURSES_URL,
null,
new Response.Listener<JSONArray>() {
#Override
public void onResponse(JSONArray coursesJsonArray) {
String name;
ArrayList<HashMap> coursesBasicInfoList = new ArrayList<>();
try {
for (int i=0; i < coursesJsonArray.length(); i++){
JSONObject courseInfo = coursesJsonArray.getJSONObject(i);
name = courseInfo.getString("name");
//ArrayList to group all the info
HashMap<String, String> currentCourseInfoList = new HashMap<>();
currentCourseInfoList.put("name", name);
coursesBasicInfoList.add(currentCourseInfoList);
}
} catch (JSONException e) {
//Do something with error
}
}
},
new Response.ErrorListener(){
#Override
public void onErrorResponse(VolleyError error){
// Do something when error occurred
}
}
){
#Override
public Map<String, String> getHeaders() {
Map<String, String> params = new HashMap<>();
params.put("Content-Type", "application/json");
return params;
}
};
// Add JsonObjectRequest to the RequestQueue
requestQueue.add(jsonArrayRequest);
return "courses";
}
The thing is, as you can see, once I have the response I build a HashMap with the key name and value of the name from the response and I put it all in coursesBasicInfoList ArrayList.
The thing is, this variable (coursesBasicInfoList) is never accessible from outside the request and what I want is to be able to put this arraylist in the "return" that you can see at the end of the function.
I know the request is asynchronous but I suppose it has to be some way to store this data from the response to use it in other methods, isn't it?
Thank you!
You can use LiveData to solve synchronization problem in asynchronous call like volley.
private MutableLiveData<ArrayList<HashMap>> requestCoursesInfo() {
MutableLiveData<ArrayList<HashMap>> mutableCoursesBasicInfoList = new MutableLiveData<>();
RequestQueue requestQueue = Volley.newRequestQueue(this.context);
JsonArrayRequest jsonArrayRequest= new JsonArrayRequest(
Request.Method.GET,
COURSES_URL,
null,
new Response.Listener<JSONArray>() {
#Override
public void onResponse(JSONArray coursesJsonArray) {
String name;
ArrayList<HashMap> coursesBasicInfoList = new ArrayList<>();
try {
for (int i=0; i < coursesJsonArray.length(); i++){
JSONObject courseInfo = coursesJsonArray.getJSONObject(i);
name = courseInfo.getString("name");
//ArrayList to group all the info
HashMap<String, String> currentCourseInfoList = new HashMap<>();
currentCourseInfoList.put("name", name);
coursesBasicInfoList.add(currentCourseInfoList);
}
} catch (JSONException e) {
//Do something with error
}
//post your result in LiveData
mutableCoursesBasicInfoList.postValue(coursesBasicInfoList);
}
},
new Response.ErrorListener(){
#Override
public void onErrorResponse(VolleyError error){
// Do something when error occurred
}
}
){
#Override
public Map<String, String> getHeaders() {
Map<String, String> params = new HashMap<>();
params.put("Content-Type", "application/json");
return params;
}
};
// Add JsonObjectRequest to the RequestQueue
requestQueue.add(jsonArrayRequest);
//Return MutableLiveData<ArrayList<HashMap>>
return mutableCoursesBasicInfoList;
}
And the observe the LiveData from your Activity/Fragment like below:
requestCoursesInfo().observe(this, new Observer<ArrayList<HashMap>>() {
#Override
public void onChanged(ArrayList<HashMap> hashMaps) {
//Do your operation here with ArrayList<HashMap>
}
});
Related
I want to send some bulk data to my php server so I constructed JSON Array. But how to send it using volley in Android. Could you anybody help. I already tried many ways but didnt work.
Below is my code for the dataset
JSONArray jsData = new JSONArray();
JSONObject others = new JSONObject();
while(crsrallansr.isAfterLast() == false) {
JSONObject Inner = new JSONObject();
try {
Inner.put("qid",crsrallansr.getString(crsrallansr.getColumnIndex("qid")));
Inner.put("qstn",crsrallansr.getString(crsrallansr.getColumnIndex("qid")));
Inner.put("result",crsrallansr.getString(crsrallansr.getColumnIndex("qid")));
} catch (JSONException e) {
e.printStackTrace();
}
jsData.put(Inner);
crsrallansr.moveToNext();
xx++;
}
Fixed the problem using StringRequest like :
reqPostanswers = new StringRequest(Request.Method.POST, url,new Response.Listener<String>() {
#Override
public void onResponse(String response) {
Log.i("posting info :",response.toString());
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
//Log.i("posting error :",error.toString());
}
}){
#Override
protected Map<String, String> getParams()
{
Map<String, String> params = new HashMap<String, String>();
params.put("user", thisuser);
params.put("answers",jsData.toString());
params.put("lickey","1761");
return params;
}
};
answerpostQueue = Volley.newRequestQueue(getApplicationContext());
answerpostQueue.add(reqPostanswers);
At the server side ( php ); the code is as follows :
$answers=json_decode($_POST['answers']);
foreach ($answers as $answer) {
$answer=json_encode($answer);
echo $answer;
$answer=json_decode($answer);
$uname=$_POST['user'];
$qid=$answer->qid;
$result=$answer->result;
$qstn=$answer->qstn;
I'm new to android development and I could not debug this error.
From volley java code
private void loadPending() {
RequestQueue queue= Volley.newRequestQueue(getApplicationContext());
int type = Request.Method.POST;
String url = "http://budgetcalc.tk/api/dailybudget/pending_list.php";
JsonArrayRequest request = new JsonArrayRequest(type, url,null,
new Response.Listener<JSONArray>(){
#Override
public void onResponse(JSONArray response) {
setPendingList(response);
}
},
new Response.ErrorListener(){
#Override
public void onErrorResponse(VolleyError error) {
error.printStackTrace();
Toast.makeText(getApplicationContext(), "Error "+error.getMessage(), Toast.LENGTH_SHORT).show();
}
}){
#Override
protected Map<String, String> getParams() throws AuthFailureError {
HashMap<String, String> params = new HashMap<String, String>();
params.put("userName",userName);
return params;
}
};
queue.add(request);
}
private void setPendingList(JSONArray response) {
List<HashMap<String,String>> list=new ArrayList<>();
Toast.makeText(this, "came to setPending", Toast.LENGTH_SHORT).show();
for (int i=0;i<response.length();i++){
try {
JSONObject obj=response.getJSONObject(i);
HashMap<String,String> map= new HashMap<String,String>();
map.put("id",obj.getString("id"));
map.put("item_name",obj.getString("item_name"));
map.put("item_amount",obj.getString("item_amount"));
map.put("item_type",obj.getString("itme_type"));
list.add(map);
} catch (JSONException e) {
e.printStackTrace();
}
}
//1. Layout File
int layout = R.layout.today_done_list_layout;
//2. View List
int[] views = {R.id.today_pending_list_item_name, R.id.today_pending_list_item_amount,R.id.today_pending_list_item_type,R.id.id };
//3. Column List
String[] cols = {"item_name", "item_amount","item_type","id"};
//4. Create Simple Adapter
SimpleAdapter adapter = new SimpleAdapter(this, list, layout, cols, views);
ListView lv = findViewById(R.id.today_pending_list);
lv.setAdapter(adapter);
}
From server side use post userName value and return JSONarray,when I checked the url with my userName using POSTMAN it gives
[{"id":"9","item_name":"pen","item_amount":"1","itme_type":"Income"},{"id":"11","item_name":"pen\n\n","item_amount":"1","itme_type":"Income"}]
But I get a error from logcat
org.json.jsonexception end of input at character 0 of volley
I think userName parameter is not going to the server when I use this volley request
I have a web service which gives data in JSON array format. Right now the data is being fetched just by passing the URL. But now I want to pass a parameter to get the JSON response. This web service has GET & POST methods.
I tried with Volley - Sending a POST request using JSONArrayRequest answer, but I couldn't implement it in my code. It would be really helpful if somebody could explain, how to achieve this in my code.
This is how my code looks like
String HTTP_SERVER_URL = "https://192.168.1.7/STUDENTWS/Default.asmx/StudentDataJson?InFacultyID=string";
public void JSON_WEB_CALL(){
//mSwipeRefreshLayout.setRefreshing(true);
jsonArrayRequest = new JsonArrayRequest(HTTP_SERVER_URL,
new Response.Listener<JSONArray>() {
#Override
public void onResponse(JSONArray response) {
JSON_PARSE_DATA_AFTER_WEBCALL(response);
}
},
new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
}
});
requestQueue = Volley.newRequestQueue(this);
requestQueue.add(jsonArrayRequest);
}
public void JSON_PARSE_DATA_AFTER_WEBCALL(JSONArray array){
for(int i = 0; i<array.length(); i++) {
DataModel GetDataModel = new DataModel();
JSONObject json = null;
try {
json = array.getJSONObject(i);
GetDataModel.setId(json.getString("STUDENTID"));
GetDataModel.setPlateNo(json.getString("GRADE"));
GetDataModel.setPlateCode(json.getString("HOUSE"));
}
catch (JSONException e)
{
e.printStackTrace();
}
DataAdapterClassList.add(GetDataModel);
mSwipeRefreshLayout.setRefreshing(false);
}
recyclerViewadapter = new NewRecyclerViewAdapter(DataAdapterClassList, this);
recyclerView.setAdapter(recyclerViewadapter);
if (array.length()!=0) {
SHOW_ALERT(array);
sendNotification(recyclerView, array);
}
}
For get with params you should create StringRequest. For example:
RequestQueue queue = Volley.newRequestQueue(context);
StringRequest sr = new StringRequest(Request.Method.GET, "http://headers.jsontest.com/",
new Response.Listener<String>() {
#Override
public void onResponse(String response) {
Log.e("HttpClient", "success! response: " + response.toString());
}
},
new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Log.e("HttpClient", "error: " + error.toString());
}
})
{
#Override
protected Map<String,String> getParams(){
Map<String,String> params = new HashMap<String, String>();
params.put("user","YOUR USERNAME");
params.put("pass","YOUR PASSWORD");
return params;
}
#Override
public Map<String, String> getHeaders() throws AuthFailureError {
Map<String,String> params = new HashMap<String, String>();
params.put("Content-Type","application/x-www-form-urlencoded");
return params;
}
};
// for json object
Map<String, String> jsonParams = new HashMap<String, String>();
jsonParams.put("fullname",fullName);
jsonParams.put("email",email);
jsonParams.put("password",password);
// for json array make any list.List will be converted to jsonArray
// example-----
// ArrayList<String> jsonParams =new ArrayList();
// jsonParams.add("Test1")
// jsonParams.add("Test2")
JsonObjectRequest objectRequest=new JsonObjectRequest(Request.Method.POST, url, new JSONObject(jsonParams), new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Log.e(TAG, "onErrorResponse: ",error );
Toast.makeText(ActivitySignUp.this,error.getMessage(), Toast.LENGTH_LONG).show();
}
}){
#Override
public Map<String, String> getHeaders() throws AuthFailureError {
HashMap<String,String> header=new HashMap<String, String>();
header.put("Content-Type","application/json");
return header;
}
};
If you want to pass a param to your server, then you might wanna do a POST method, else.. if you only wanted to get the data, then GET method is the best way... there's also header that you can use to pass data, but, I wouldn't recommend to use header for sending params... that's a sore eyes
Edit
//Set you method POST or GET
JsonObjectRequest(Request.Method.GET(/*here can set to POST too*/), url, null,
new Response.Listener<JSONObject>()
{
#Override
public void onResponse(JSONObject response) {
// display response
Log.d("Response", response.toString());
}
},
new Response.ErrorListener()
{
#Override
public void onErrorResponse(VolleyError error) {
Log.d("Error.Response", response);
}
}
);
The Android code is not sending the parameters when using JsonArrayRequest.
If I use StringRequest instead of JsonArrayRequest how do I convert the response from String to JSONObject to display it in a RecyclerView?
Intent intent = getIntent();
final String userID = intent.getExtras().getString("userID");
recyclerView = (RecyclerView)findViewById(R.id.display_expenses_recycler_view_id);
layoutManager = new LinearLayoutManager(this);
recyclerView.setLayoutManager(layoutManager);
recyclerView.setHasFixedSize(true);
JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(Request.Method.POST, expensesDisplay_url, (String) null,
new Response.Listener<JSONArray>() {
#Override
public void onResponse(JSONArray response) {
int count = 0;
Log.i("Response", String.valueOf(response));
while (count < response.length()) {
try {
JSONObject jsonObject = response.getJSONObject(count);
ExpensesDetails expensesDetails = new ExpensesDetails(jsonObject.getString("Expenses"),
jsonObject.getString("Description"), jsonObject.getString("datetime"));
arrayList.add(expensesDetails);
count++;
} catch (JSONException e) {
e.printStackTrace();
}
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(DisplayExpenses.this, "Error", Toast.LENGTH_LONG).show();
error.printStackTrace();
}
}) {
#Override
protected Map<String, String> getParams() throws AuthFailureError {
Map<String, String> params = new HashMap<String, String>();
params.put("userID", userID);
return params;
}
};
Log.i("Array", String.valueOf(arrayList));
MySingleton.getMyInstance(DisplayExpenses.this).addToRequestQueue(jsonArrayRequest);
adapter = new RecyclerAdapterExpenses(arrayList);
recyclerView.setAdapter(adapter);View.setAdapter(adapter);
This is the result sent from the server:
[
{
"Expenses":"0",
"Description":"car",
"datetime":"2016-10-25 21:10:57"
},
{
"Expenses":"2000",
"Description":"Car",
"datetime":"2016-10-25 21:46:05"
},
{
"Expenses":"5000",
"Description":"House payment",
"datetime":"2016-10-25 21:47:11"
},
{
"Expenses":"200",
"Description":"",
"datetime":"2016-10-26 20:51:42"
},
{
"Expenses":"500",
"Description":"",
"datetime":"2016-10-26 23:55:21"
}
]
Are you sure the user ID isn't being given? You have an empty RecyclerView until the Volley request finishes. And your Log.i statement happens before Volley completes, so you'll see an empty list...
You need an adapter.notifyDataSetChanged() within the onResponse call after the while loop to tell the adapter to display the data you added.
Not too sure what View is here... but you likely don't need the same adapter on two views.
recyclerView.setAdapter(adapter);View.setAdapter(adapter);
if i tried to use StringRequest instead of JsonArrayRequest how will i convert the string response from String to JSONObject to display them in a RecyclerView
You have a String response from onResponse, so use the constructor for JSONArray that takes a String.
JSONArray array = new JSONArray(response);
Note: that requires a try-catch.
I need to call an api that expects a string array as a POST parameter. So for an example of an API definition:
POST api/names
POST parameter expected is an array of names and some other attributes like below:
{ names: [ "John", "Bill" ], department: "Engineering" }
I am currently using a custom Volley framework as described in the Android documentation but it seems like the parameters from Volley can only be passed as a Map of (String, String as key and value). I already have the array from my Android app, ready to be passed as a post parameter but this Volley expects a String.
I tried to convert my array using Arrays.toString(myStringArray) and passed it like below but it does not work.
String[] namesArray = new String[1];
namesArray[0] = "Bill";
Map<String, String> mapParams = new HashMap<String, String>();
mapParams.put("department", "Computer Science");
mapParams.put("names", Arrays.toString(namesArray));
// Then call the Volley here passing the mapParams.
How can I call the api that expects a String of array when I can only use a String from Volley?
I will give you full code to post JsonObject on volley, through POST method.
JSONObject js = new JSONObject();
try {
js.put("genderType", "MALE");
}
} catch (JSONException e) {
e.printStackTrace();
}
String url = "LINK TO POST/";
// Make request for JSONObject
JsonObjectRequest jsonObjReq = new JsonObjectRequest(
Request.Method.POST, url, js,
new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
Log.e(TAG, "Response_Code from Volley" + "\n" + response.toString() + " i am king");
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
VolleyLog.e(TAG, "Error: " + error.getMessage());
NetworkResponse response = error.networkResponse;
if (error instanceof ServerError && response != null) {
try {
String res = new String(response.data,
HttpHeaderParser.parseCharset(response.headers, "utf-8"));
// Now you can use any deserializer to make sense of data
Log.e(TAG, "onErrorResponse: of uploadUser" + res);
// JSONObject obj = new JSONObject(res);
} catch (UnsupportedEncodingException e1) {
// Couldn't properly decode data to string
e1.printStackTrace();
}
}
}
}) {
#Override
public Map<String, String> getHeaders() throws AuthFailureError {
HashMap<String, String> headers = new HashMap<String, String>();
headers.put("Content-Type", "application/json");
return headers;
}
};
Log.e(TAG, "uploadUser: near volley new request ");
// Adding request to request queue
Volley.newRequestQueue(this).add(jsonObjReq);
}
Put anything you need in the js object with key and its values
Use JsonObjectRequest and simply pass a JSONObject. There's a full example here
public void makePostRequest(final Map<String,String> myMap,String MEDIA_URL,final VolleyResponse callback)
{
VolleySingleton VS;
Log.e("URL",MEDIA_URL);
VS=VS.getInstance();
RequestQueue rq=VS.getRequestQueue();
StringRequest stringRequest = new StringRequest(Request.Method.POST,MEDIA_URL,
new Response.Listener<String>() {
#Override
public void onResponse(String s) {
callback.onSuccess(s);
}
},
new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError volleyError) {
callback.onError();
}
}){
#Override
protected Map<String, String> getParams() throws AuthFailureError {
Map<String,String> params = new Hashtable<String, String>();
Iterator<Map.Entry<String, String>> iterator = myMap.entrySet().iterator();
while(iterator.hasNext()) {
Map.Entry<String,String> pairs = (Map.Entry<String,String>)iterator.next();
String value = pairs.getValue();
String key = pairs.getKey();
params.put(key,value);
Log.e("Key","Value"+value);
}
return params;
}
};
//Creating a Request Queue
// RequestQueue requestQueue = Volley.newRequestQueue(this);
DefaultRetryPolicy retryPolicy = new DefaultRetryPolicy(0, -1, DefaultRetryPolicy.DEFAULT_BACKOFF_MULT);
stringRequest.setRetryPolicy(retryPolicy);
//Adding request to the queue
rq.add(stringRequest);
}
Where the VolleyResponse is a simple custom interface like this
public interface VolleyResponse {
void onSuccess(String resp);
void onError();
}