Develop Reference

Waiting for multiple volley calls

I'm trying to do something similar to the answer of this question
I'm using Volley rather than Retrofit, and have adapted my code accordingly. For me the callback handlers never actually fire, although the counDownLatch does timeout after the specified number of seconds. I suspect the handlers never fire because the countDownLatch.awaiting is using all the processing on the current thread. Or am I missing something else?
public void queryUmbrellaServer() {
ArrayList<String> identifiers = getHardwareIdentifiers(context);
VolleyLog.DEBUG = true;
CountDownLatch countDownLatch = new CountDownLatch(identifiers.size());
// creating a new variable for our request queue
final RequestQueue[] queue = {Volley.newRequestQueue(context)};
queue[0].start();
for (int i = 0; i < identifiers.size(); i++) {
String url = umbrellaServerUrl + identifiers.get(i) + "/";
Log.i(LOG_TAG, "Inside Loop " + url);
JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.GET, url, null,
new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
try {
countDownLatch.countDown();
String serverName = response.getString("mdm_server_url");
String registrationUrl = response.getString("registration_url");
String isDeviceOwner = response.getString("device_owner");
Toast.makeText(context, "Retrieved server name from umbrella server: " + serverName, Toast.LENGTH_LONG).show();
setMdmInfo(serverName, registrationUrl, isDeviceOwner);
Log.i(LOG_TAG, "Successful response");
//queue[0].stop();
results.add(isDeviceOwner.toString());
} catch (JSONException e) {
e.printStackTrace();
Log.d(LOG_TAG, "Error in parsing response");
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
countDownLatch.countDown();
if(error.networkResponse.data!=null) {
String jsonString = new String(error.networkResponse.data);
//Log.d(LOG_TAG, jsonString);
try {
JSONObject jsonObject = new JSONObject(jsonString);
String msg = jsonObject.getString("message");
if (!msg.equals("Device not found")) {
Log.d(LOG_TAG, "Error in retrieving response from server");
//queue[0].stop();
results.add("false");
}
else {
Log.d(LOG_TAG, "No device found");
results.add("false");
}
} catch (JSONException e) {
e.printStackTrace();
Log.d(LOG_TAG, "Error in retrieving response from server");
//queue[0].stop();
results.add("UNSET");
}
}
else {
Log.d(LOG_TAG, "Error in retrieving response from server");
//queue[0].stop();
results.add("UNSET");
}
}
});
// Add the request to the RequestQueue.
queue[0].add(jsonObjectRequest);
}
try {
countDownLatch.await(1L * identifiers.size(), TimeUnit.SECONDS); // join thread with timeout of second for each item
} catch (InterruptedException e) {
e.printStackTrace();
}
Log.d(LOG_TAG,"outside loop" + results);
}
I expected the results arrayList should get populated before the countDownLatch countdown completes, but I haven't been able to get any results.

Parse REST response message using retrofit and observable

My API returns this when I use wrong login information (using postman):
{
"error": {
"statusCode": 401,
"name": "Error",
"message": "login failed",
"code": "LOGIN_FAILED",
"stack": "Error: login failed\n at ...path..."
}
}
I am using this method to get the response message:
private void handleResponse(retrofit2.Response<Response> response) {
if (response.isSuccessful()) {
emailField.setText(null);
passwordField.setText(null);
Intent intent = new Intent(getActivity(), MainActivity.class);
startActivity(intent);
} else {
try {
showSnackBarMessage(response.errorBody().string());
} catch (Exception e) {
showSnackBarMessage(e.getMessage());
}
}
}
And the output (what snackbar shows) is the same as postman returns.
handleresponse parameter retrofit2.Response<Response> response consists of retrofit2 Response, and my own <Response> class which looks like this:
public class Response {
#SerializedName("message")
#Expose
private String message;
public String getMessage() {
return message;
}
}
How can I get only message to show in snackbar?
I have tried the following code, but I get only No value for message.
try {
JSONObject jObjError = new JSONObject(response.errorBody().string());
Toast.makeText(getContext(), jObjError.getString("message"), Toast.LENGTH_LONG).show();
} catch (Exception e) {
Toast.makeText(getContext(), e.getMessage(), Toast.LENGTH_LONG).show();
}

According to your json the response error body is an object with a field error which contains a field message. This means you first need to get the error object and then the message:
JSONObject jObjError = new JSONObject(response.errorBody().string()).getJSONObject("error");
Toast.makeText(getContext(), jObjError.getString("message"), Toast.LENGTH_LONG).show();

Nested volley request with Singleton class returns null

I am getting a error in my code. The outer request returns a data but the inner loop returns null.
What I am doing here is: I am requesting some data and again using the id that I get from the first request, i use it to send another request. Although I am receiving the first response, I am getting ERRORNull message in the second nested request.
I am sure that the url is correct. I have not been able to find the solution to this problem.
private ArrayList<Item> fetchApiData(){
String url="http://www.gadgetsinnepal.com.np/wp-json/wp/v2/posts/";
JsonArrayRequest jsArrayRequest = new JsonArrayRequest
(Request.Method.GET, url, null, new Response.Listener<JSONArray>() {
#Override
public void onResponse(JSONArray response) {
try {
// Parsing json array response
// loop through each json object
for (int i = 0; i < response.length(); i++) {
JSONObject item = (JSONObject) response
.get(i);
String id = item.getString("id");
String date = item.getString("date");
JSONObject titleobj = item
.getJSONObject("title");
String title= titleobj.getString("rendered");
String featuredMedia= item.getString("featured_media");
Toast.makeText(getApplicationContext(), "ID :" + id +" Date: "+ date+ " Title "+ title + featuredMedia,
Toast.LENGTH_SHORT).show();
JsonObjectRequest jsonObjReq = new JsonObjectRequest(Request.Method.GET,
"http://www.gadgetsinnepal.com/wp-json/wp/v2/media/"+featuredMedia, null, new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject nested_response) {
try {
// Parsing json object response
// response will be a json object
JSONObject guilld = nested_response.getJSONObject("guid");
String featured_img_url = guilld.getString("rendered");
String nestid=nested_response.getString("id");
Toast.makeText(getApplicationContext(),nested_response.toString()+"IMAGE" + nestid,Toast.LENGTH_LONG).show();
} catch (JSONException e) {
e.printStackTrace();
Toast.makeText(getApplicationContext(),
"Error: " + e.getMessage(),
Toast.LENGTH_LONG).show();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(getApplicationContext(),
"ERROR"+error.getMessage(), Toast.LENGTH_LONG).show();
}
});
MySingleton.getInstance(getApplicationContext()).addToRequestQueue(jsonObjReq);
}
} catch (JSONException e) {
e.printStackTrace();
Toast.makeText(getApplicationContext(),
"Error: " + e.getMessage(),
Toast.LENGTH_LONG).show();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
// TODO Auto-generated method stub
}
});
MySingleton.getInstance(this).addToRequestQueue(jsArrayRequest);
}

This problem was solved by carefully examining where the error log was giving.
Having unique logs in your methods will make finding the place where the problem occurs easier to find.
In this case we found that something was happening in:
#Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(getApplicationContext(),
"ERROR"+error.getMessage(), Toast.LENGTH_LONG).show();
}
Further investigation showed we got a response code 503 message there.
Reasons for this to happen: lifewire.com/503-service-unavailable-explained-2622940
Increasing the time out of the request seems to prevent this from occurring again.

Sending POST Request and Receive Json Responds using Retrofit Unable to use Responds data I need to pass it to another activity

I am using Retrofit for sending POST request.Server return's a JSON Response and i am able to parse the response in the callback method. I need to pass the data from server to another activity. But i can't use the response data outside.
api.LoginUser(
Email.getText().toString(), // passing value to interface of retrofit
Password.getText().toString(),
new Callback<Response>() {
#Override
public void success(Response result, Response response) {
BufferedReader reader = null;
String output = "";
try {
reader = new BufferedReader(new InputStreamReader(result.getBody().in()));
output = reader.readLine();
} catch (IOException e) {
e.printStackTrace();
}
//Json PArsing
try {
JSONObject mainObject = new JSONObject(output);
JSONObject dataObj = mainObject.getJSONObject("data");
String id = dataObj.getString("id");
String name = dataObj.getString("name");
n=name;
Log.d("jsontext", n); //This works
}
catch(JSONException e)
{
e.printStackTrace();
}
Toast.makeText(MainActivity.this, output, Toast.LENGTH_LONG).show();
}
#Override
public void failure(RetrofitError error) {
//If any error occured displaying the error as toast
Toast.makeText(MainActivity.this, error.toString(), Toast.LENGTH_LONG).show();
}
}
);
I can't use this when it executes App crashes.its ok now there is no value in the variable.how to get values out of the callback Responds OnSuccess method???
Log.d("outer",n);
Intent dash = new Intent(this,Dashboard.class);
dash.putExtra("Value",fi);
startActivity(dash);
}

You can create an object and implement Serializable:
class User implements Serializable {
...
}
Then put object User to bundle, add to intent:
Bundle bundle = new Bundle();
bundle.putSerializable("data", user);
Intent intent = new Intent(this, YourClass.class);
intent.putExtras(bundle);
startActivity(intent);
Hope it help you.

Hold all data in a string and using intent app another activity and parse it;

You can do it as follows
public void onSuccess(int statusCode, Header[] headers,
byte[] response) {
try {
BufferedReader br = new BufferedReader(
new InputStreamReader(new ByteArrayInputStream(
response)));
String st = "";
String st1 = "";
while ((st = br.readLine()) != null) {
st1 = st1 + st;
}
showStoreData(st1);
} catch (Exception e) {
e.printStackTrace();
}
}
#Override
public void onFailure(int statusCode, Header[] headers,
byte[] errorResponse, Throwable e) {
// called when response HTTP status is "4XX" (eg. 401, 403, 404)
Log.e("FAIL", "FAIl" + statusCode);
}
#Override
public void onRetry(int retryNo) {
// called when request is retried
}
});
after that
public void showStoreData(String st) {
Intent intent = new Intent(this, YourClass.class);
intent.putExtras(st);
startActivity(intent);
}

You should use an interface that you initialize from the calling method and pass as a parameter into you request class, that way you can call the requests from anywhere and get the callback response back to where you called it from, an example would be:
A general interface, separated in another file:
public interface SomeCustomListener<T>
{
public void getResult(T object);
}
In the class holding your call (complete the stuff you need):
public void someRequestReturningString(Object param1, final SomeCustomListener<String> listener)
{
//here you initialize what you need... it's your stuff
response.enqueue(new Callback<ResponseBody>()
{
#Override
public void onResponse(Call<ResponseBody> call, retrofit2.Response<ResponseBody> rawResponse)
{
try
{
String response = rawResponse.body().string();
// do what you want with it and based on that...
//return it to who called this method
listener.getResult("someResultString");
}
catch (Exception e)
{
e.printStackTrace();
listener.getResult("Error1...");
}
}
#Override
public void onFailure(Call<ResponseBody> call, Throwable throwable)
{
try
{
// do something else in case of an error
listener.getResult("Error2...");
}
catch (Exception e)
{
throwable.printStackTrace();
listener.getResult("Error3...");
}
}
});
}
Then from where you're calling the request (could be anywhere, Fragments, onClicks, etc):
public class BlaBla
{
//.....
public void someMethod()
{
NetworkManager.getInstance().someRequestReturningString(someObject, new SomeCustomListener<String>()
{
#Override
public void getResult(String result)
{
if (!result.isEmpty())
{
//do what you need with the result...
}
}
});
}
}
If you need more context, you can refer to this SO thread.
Hope this helps!

random com.android.volley.NoConnection error, java.io.InterruptedIOException, statuscode=0

I have a native android app using volley framework to fetch data from a PHP server end script.
It worked well on most time, but I have 20% percentage failure.
The error says:
com.android.volley.NoConnection, java.io.InterruptedIOException.
I debugged that I found the statuscode = 0, which obviously was wrong.
I have no idea what can be the reason? Since it is working most time so there should be no obvious error code.
FYI, those PHP script on the server end works very well for my IOS app.
Please allow me post my code here:
retryConnBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
txtOut.append("\n");
txtOut.append("Button with Retry Click");
Log.d("Click", "Button Click");
final String url = "https://www.myserver.com/api/getBalanceInfoTest?token=7ff3317a4f3dc07d0c297a7d16d2049c&t=" + System.currentTimeMillis();
//final String url = "http://192.168.1.23/base/test/";
JsonObjectRequest getRequest = new JsonObjectRequest(Request.Method.GET, url, null,
new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
txtOut.append("\n");
txtOut.append("Result with Retry:");
txtOut.append(response.toString());
Log.d("Response", response.toString());
VolleyLog.e("Response:", response.toString());
}
},
new Response.ErrorListener(){
#Override
public void onErrorResponse(VolleyError error) {
txtOut.append("\n");
txtOut.append("Error with Retry:");
txtOut.append(error.toString());
Log.d("Error.Response", error.toString());
VolleyLog.e("Error:", error.getMessage());
}
});
getRequest.setRetryPolicy(new DefaultRetryPolicy(5000, 5, DefaultRetryPolicy.DEFAULT_BACKOFF_MULT));
queue.add(getRequest);
queue.start();
}
});
}
And for more information, the output of my PHP script is:
{"hsaBalance":"1000.00"}, created by Json_encode() function of PHP.

I have fixed this bug.
It is not a network issue.
queue.add(getRequest);
queue.start();
should be
queue.add(getRequest);
So the key is we should remove queue.start().

Michael Cheng is right,because volley had start the RequestQueue when we call newRequestQueue as below:
public static RequestQueue newRequestQueue(Context context, HttpStack stack) {
File cacheDir = new File(context.getCacheDir(), DEFAULT_CACHE_DIR);
String userAgent = "volley/0";
try {
String packageName = context.getPackageName();
PackageInfo info = context.getPackageManager().getPackageInfo(packageName, 0);
userAgent = packageName + "/" + info.versionCode;
} catch (NameNotFoundException e) {
}
if (stack == null) {
if (Build.VERSION.SDK_INT >= 9) {
stack = new HurlStack();
} else {
// Prior to Gingerbread, HttpUrlConnection was unreliable.
// See: http://android-developers.blogspot.com/2011/09/androids-http-clients.html
stack = new HttpClientStack(AndroidHttpClient.newInstance(userAgent));
}
}
Network network = new BasicNetwork(stack);
RequestQueue queue = new RequestQueue(new DiskBasedCache(cacheDir), network);
queue.start();
return queue;
}
and when we call start, volley will call stop to “make sure any currently running dispatchers are stopped”，in stop method volley does this below:
public void stop() {
if (mCacheDispatcher != null) {
mCacheDispatcher.quit();
}
for (int i = 0; i < mDispatchers.length; i++) {
if (mDispatchers[i] != null) {
mDispatchers[i].quit();
}
}
}
and the quit method does this below:
public void quit() {
mQuit = true;
interrupt();
}
maybe you can see the reason,why interrupted.
More, interrupt method does this below:
public void interrupt() {
// Interrupt this thread before running actions so that other
// threads that observe the interrupt as a result of an action
// will see that this thread is in the interrupted state.
nativeInterrupt();
synchronized (interruptActions) {
for (int i = interruptActions.size() - 1; i >= 0; i--) {
interruptActions.get(i).run();
}
}
}
the reason maybe this as metioned above:
Interrupt this thread before running actions so that other threads that observe the interrupt as a result of an action will see that this thread is in the interrupted state.

You are having sometimes problems with your connection. Look at InterruptedIOException API:
InterruptedIOException Signals that an I/O operation has been interrupted. An InterruptedIOException is thrown to indicate that an input or output transfer has been terminated because the thread performing it was interrupted.
so only you can do is to catch the possible exceptions occuring when converting JSon and having a workaround for this.
// rest of your code...
final String url = "https://www.myserver.com/api/getBalanceInfoTest?token=7ff3317a4f3dc07d0c297a7d16d2049c&t=" + System.currentTimeMillis();
try {
JsonObjectRequest getRequest = new JsonObjectRequest(Request.Method.GET, url, null,
// rest of your code...
queue.add(getRequest);
queue.start();
} catch (InterruptedIOException e) {
// do something when fail print error, show a toast
System.out.err("Error, connection interrupted" + e.getMessage());
Toast.makeText(getApplicationContext(), "press button again", Toast.LENGTH_LONG).show();
}