Develop Reference

getting new data from a json file using volley

I have an android java app and i need some data from a json file so i used volley to get data from json
my problem is when i change data on the json file i should uninstall the app and install it again then get the new data otherwise it keeps the old data even after killing it from ram
RequestQueue requestQueue = Volley.newRequestQueue(this);
jsonObjectRequest = new JsonObjectRequest(Request.Method.GET, LINK, null, new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
try {
JSONArray jsonArrayVariabls = response.getJSONArray("variables");
JSONObject var = jsonArrayVariabls.getJSONObject(0);
Variables.name = var.getString("name");
Variables.adresse=var.getString("adresse");
callBack.onSuccess();
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
}
});
jsonObjectRequest.setRetryPolicy(new DefaultRetryPolicy(DefaultRetryPolicy.DEFAULT_TIMEOUT_MS, DefaultRetryPolicy.DEFAULT_MAX_RETRIES, DefaultRetryPolicy.DEFAULT_BACKOFF_MULT));
requestQueue.add(jsonObjectRequest);

The problem was from cache so you need to clear it before request using this line
requestQueue.getCache().clear();

Getting response data in Volley OnErrorResponse

I am hitting API on the server. It is working perfectly but when I run it in my app I am getting volley onErrorResponse along with data . I am not able to understand how it is possible. I am sharing code and error image. Please check.
private void callProductsApi() {
String tag_json_obj = "json_obj_req";
String url = Constants.GET_PRODUCTS;
pBar.setVisibility(View.VISIBLE);
JSONObject params = new JSONObject();
try {
params.put("token", Constants.token);
} catch (Exception e) {
e.printStackTrace();
}
JsonObjectRequest jsonObjReq = new JsonObjectRequest(Request.Method.POST,
url, params,
new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
Log.e("login_response", response.toString());
pBar.setVisibility(View.GONE);
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
VolleyLog.e("Error: " + error.getMessage());
Toast.makeText(Splash.this, R.string.some_error_occured, Toast.LENGTH_LONG).show();
pBar.setVisibility(View.GONE);
}
});
jsonObjReq.setRetryPolicy(new DefaultRetryPolicy(
100000,
DefaultRetryPolicy.DEFAULT_MAX_RETRIES,
DefaultRetryPolicy.DEFAULT_BACKOFF_MULT));
AppController.getInstance().addToRequestQueue(jsonObjReq, tag_json_obj);
}

The api should return success code which is 200, 201 and so on response. if it returns
other response in line of 400 or 500 it will display the correct json but in error method.

Using volley to make web service call

I have a web api setup and one of the endpoints in the API takes a JSON object (which in the API gets resolved to a .NET object).
Using Postman I can successfully call the post endpoint, here is the URL
https://example.com/api/helprequests
And here is the JSON which I include in the Postman request
{"Title":"Test Title", "Message":"Test Message"}
Everything works well in Postman, but I am trying to call this API from an Android app using Volley.
Here is the relevant code
String webAddress = "http://example.com/api/helprequests/";
RequestQueue queue = Volley.newRequestQueue(this);
StringRequest stringRequest = new StringRequest(Request.Method.POST, webAddress,
new Response.Listener<String>() {
#Override
public void onResponse(String response) {
Log.d("RESPONSE", response);
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Log.d("RESPONSE", "That didn't work!");
}
}) {
#Override
public String getBodyContentType() {
return "application/json";
}
#Override
public byte[] getBody() throws AuthFailureError {
try {
Map<String, String> params = new HashMap<String, String>();
params.put("Title","Test title");
params.put("Message", "Test message");
} catch (Exception ex) {
VolleyLog.wtf("Unsupported Encoding");
return null;
}
return null;
}
};
queue.add(stringRequest);
When I run this I get the following error:
E/Volley: [50225] BasicNetwork.performRequest: Unexpected response code 500 for https://example.com/api/helprequests
How do I add post data to a Volley request?

Instead of using the StringRequest do use JsonObjectRequest.
String webAddress = "http://example.com/api/helprequests/";
RequestQueue queue = Volley.newRequestQueue(this);
JSONObject object = new JSONObject();
try {
object.put("Title", "my title");
object.put("Message", "my message");
} catch (JSONException e) {
}
JsonObjectRequest request = new JsonObjectRequest(Request.Method.POST, webAddress,object, new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject object) {
Log.d("RESPONSE", object.toString());
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError volleyError) {
Log.d("RESPONSE", "That didn't work!");
}
});
queue.add(request);

String webAddress = "http://example.com/api/helprequests/";
RequestQueue queue = Volley.newRequestQueue(this);
JSONObject jsonObject= new JSONObject();
try {
jsonObject.put("Title", "my title");
jsonObject.put("Message", "my message");
} catch (JSONException e) {
}
RequestQueue queue = Volley.newRequestQueue(getApplicationContext());
JsonObjectRequestWithHeader jsonObjReq = new JsonObjectRequestWithHeader(Request.Method.POST,
webAddress , jsonObject, new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
Log.v("Response0", response.toString());
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
VolleyLog.d("Response", "Error: " + error.getMessage());
pd.dismiss();
}
});
int socketTimeout = 50000;//30 seconds - change to what you want
RetryPolicy policy = new DefaultRetryPolicy(socketTimeout, DefaultRetryPolicy.DEFAULT_MAX_RETRIES,
DefaultRetryPolicy.DEFAULT_BACKOFF_MULT);
jsonObjReq.setRetryPolicy(policy);
queue.add(jsonObjReq);
return null;
}

Send image via JsonObjectRequest Volley in Android?

I have a POST method send a JsonObject via Volley:
JsonObjectRequest request = new JsonObjectRequest(Request.Method.POST, url, postBody, new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
log("success");
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
log("" + error);
}
});
request.setRetryPolicy(new DefaultRetryPolicy(10000, 0, DefaultRetryPolicy.DEFAULT_BACKOFF_MULT));
Volley.newRequestQueue(this).add(request);
With postBody:
JSONObject postBody = new JSONObject();
try {
postBody.put("name", "rome");
//postBody.put("image", file?);
} catch (JSONException e) {
log("" + e);
}
I want to send a image file with key "image" above. This file type is the same with file of form-data in PostMan (not url of file).
Is there anyway to do it? Thanks.

com.android.volley.ParseError: org.json.JSONException

I got this error from volley library
#Override
public void onErrorResponse(VolleyError error) {
error.printStackTrace();
}
the error
com.android.volley.ParseError: org.json.JSONException: Value [{"id":"admin","name":"Admin"}] of type org.json.JSONArray cannot be converted to JSONObject
How can I receive the result as string and then I will process it using jackson ?

If you want to receive the result as a string don't use the JSONRequest. Go with the simple Request class.
Your problem is pretty simple the server is giving back a JSONArray with just one element inside.
A JSONArray is not a JSONObject. That's why the parsing is failing.

We Have to use JsonArrayRequest instead of JsonObjectRequest. The code as:
RequestQueue queue = Volley.newRequestQueue(this);
final String url = "http://192.168.88.253/mybazar/get_product_list.php";
// prepare the Request
JsonArrayRequest getRequest = new JsonArrayRequest(Request.Method.GET, url, null,
new Response.Listener<JSONArray>()
{
#Override
public void onResponse(JSONArray response) {
// display response
Log.d("Response", response.toString());
}
},
new Response.ErrorListener()
{
#Override
public void onErrorResponse(VolleyError error) {
Log.d("Error.Response", error.toString());
}
}
);
// add it to the RequestQueue
queue.add(getRequest);
Hope, it's solve the problem.

I noticed that there is class JsonArrayRequest supported by volley so I use this class and the problem solved, I was using JsonObjectRequest
https://android.googlesource.com/platform/frameworks/volley/+/43950676303ff68b23a8b469d6a534ccd1e08cfc/src/com/android/volley/toolbox

Probably the below logic will work for you:
JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(
Request.Method.GET,
url,
null,
new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
try {
JSONObject jsonObject1 = new JSONObject(response.toString());
JSONArray jsonArray = jsonObject1.getJSONArray("statewise");
Log.d("Json response", "onResponse: "+jsonObject1.toString());
for (int i = 0; i < jsonArray.length; i++) {
JSONObject jsonObject = jsonArray.getJSONObject(i);
//Here you will get your result so can use textview
//to populate the result
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Log.d(TAG, "onErrorResponse: "+error);
}
});
RequestQueue requestQueue = Volley.newRequestQueue(this);
requestQueue.add(jsonObjectRequest);
}