Develop Reference

Arraylist that sometimes contain data, and sometimes not

A newbie for here.
I'm working in an app with Android and a strange thing happens to me with a While loop. I make a series of requests to the database with volley library and it returns the data well. No problem.
The problem, i think, is in the last function DameColorPlato(), because sometimes the code accesses the while loop and it passes through it well, but sometimes it does not, and it returns the default value of the CC variable (#000000) and it does not show me well the colors of the text.
This is my code (In summary):
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_menu);
Bundle datos = getIntent().getExtras();
id_usuario = datos.getString("id_usuario");
idCentro = datos.getString("id_centro");
fecha_actual = datos.getString("fechaActual");
fecha_actual_SQL = datos.getString("fechaActualSQL");
plato1 = (TextView)findViewById(R.id.textView4);
plato2 = (TextView)findViewById(R.id.textView3);
ObtPlatos_volley(idCentro, fecha_actual_SQL);
ObtColores_volley();
public void ObtPlatos_volley(final String id_centro, final String fecha_actual_SQL){
String url = "http://neton.es/WS_neton/menu_dia.php?id_centro="+id_centro+"&fecha_actual_SQL="+fecha_actual_SQL;
StringRequest eventfulRequest = new StringRequest(Request.Method.GET, url,
new Response.Listener<String>() {
#Override
public void onResponse(String response) {
try {
JSONArray jsonArray = new JSONArray(response);
for (int i=0; i<jsonArray.length(); i++) {
platouno = jsonArray.getJSONObject(i).getString("plato1");
platodos = jsonArray.getJSONObject(i).getString("plato2");
platounoColor = jsonArray.getJSONObject(i).getInt("tipo1");
platodosColor = jsonArray.getJSONObject(i).getInt("tipo2");
}
plato1.setText(platouno);
String co1 = DameColorPlato(CodTipoPlato, ColorLetra, platounoColor);
plato1.setTextColor(Color.parseColor(co1));
plato2.setText(platodos);
String co2 = DameColorPlato(CodTipoPlato, ColorLetra, platodosColor);
plato2.setTextColor(Color.parseColor(co2));
} catch (Exception e) {
e.printStackTrace();
}
}
},
new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Log.e("Error: ", error.toString());
}
});
VolleySingleton.getInstance(this)
.addToRequestQueue(eventfulRequest);
}
public void ObtColores_volley(){
String url = "http://neton.es/WS_neton/color_platos.php";
StringRequest eventfulRequest = new StringRequest(Request.Method.GET, url,
new Response.Listener<String>() {
#Override
public void onResponse(String response) {
try {
int cod_color_letra;
String color_letra;
JSONArray jsonArray = new JSONArray(response);
for (int i=0; i<jsonArray.length(); i++){
cod_color_letra = jsonArray.getJSONObject(i).getInt("cod_tipoplato");
color_letra = jsonArray.getJSONObject(i).getString("color");
CodTipoPlato.add(cod_color_letra);
ColorLetra.add(color_letra);
}
} catch (Exception e) {
e.printStackTrace();
}
}
},
new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Log.e("Error: ", error.toString());
}
});
VolleySingleton.getInstance(this)
.addToRequestQueue(eventfulRequest);
}
public String DameColorPlato(ArrayList<Integer> CodColorL, ArrayList<String> ColorL, int tipoplato){
String CC="#000000";
int i=0;
boolean encontrado=false;
while (i < CodColorL.size() && !encontrado) {
if (tipoplato == CodColorL.get(i)) {
CC = ColorL.get(i);
encontrado = true;
}else {
i++;
}
}
return CC;
}
}
With a Toast I have found that ArrayList CodColorL and ArrayList ColorL variables sometimes come with values, and sometimes they come empty. But i cannot found the error.
Thanks in advance!
(sorry for my bad English)

As I explained out in the comments, for anyone else looking at this question, the reason why OP was seeing the issue of unreliable data is because they are making two Volley requests and expecting one to finish before implicitly.
By default, Volley requests are run in a queue but are Asynchronous which means that the requests won't necessarily finish in the order that they were started in the queue. Since OP's one request is dependent on the data from the other the correct way to do this is by synchronously running the requests. This can be done in a few ways such as using a callback from the first request or through starting the second request in the onResponse block of the first one.
One more way to achieve the same is to create your own architecture of running requests where you have a way to run all the requests on a single thread but that is over optimizing for this particular case.

Volley Request becomes too slow when phone goes to sleep and come back again to Application

I am facing the unidentified issue from several days that volley request becomes too slow when phone goes to sleep mode for some time and then return back to the app,i tried so many Retrypolicies given by volley, but none of them working correctly.below is my example code requesting volley to get data.
JsonObjectRequest movieReq = new JsonObjectRequest(
"MyURL" + session.getBusinessUserRegisterID(),
null,
new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
try {
String Connectionscount = response.getString("Connections");
String Expiredcountval = response.getString("Expired");
String Livecountval = response.getString("Live");
String NewCustomerscount = response.getString("NewCustomers");
String NewNotificationscount = response.getString("NewNotifications");
String SmsBalancecount = response.getString("SmsBalance");
String TotalCustomercount = response.getString("TotalCustomer");
Newnotificationscount.setText(NewNotificationscount);
Livecount.setText(Livecountval);
Expiredcount.setText(Expiredcountval);
Totalcustcount.setText(TotalCustomercount);
Newcustcount.setText(NewCustomerscount);
Myconnectionscount.setText(Connectionscount);
Smscount.setText(SmsBalancecount);
ringProgressDialog.dismiss();
mSwipeRefreshLayout.setRefreshing(false);
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
}
});
movieReq.setRetryPolicy(
new DefaultRetryPolicy(
10000,0,1f
)
);
AppController.getInstance().addToRequestQueue(movieReq);
First case placing second parameter of DefaultRetryPolicy greater than 0,it takes too long to give response
movieReq.setRetryPolicy(
new DefaultRetryPolicy(
10000,1,1f
)
);
Second case placing Second parameter as 0 so i can be given error if volley doesn't responds for 10 seconds(I am showing alert to retry).
movieReq.setRetryPolicy(
new DefaultRetryPolicy(
10000,0,1f
)
);

Try setting Priority high as :
#Override
public Priority getPriority() {
return Priority.HIGH;
}

How to put volley coding in main acitivity.java

This Android app is using Android Studio. The function is to scan and display data from the beacon/eddystone. The app already functions and after the scanning stops, the data saves to the local file. I need to transfer the data to the server. How can i insert the volley coding to the mainacitivity.java. I tried to put under the stopscanning button, but it shows error. Im really beginners to learn about android studio.
Here is the coding:
private void stopScanning(Button scanButton) {
try {
beaconManager.stopRangingBeaconsInRegion(region);
} catch (RemoteException e) {
// TODO - OK, what now then?
}
String scanData = logString.toString();
if (scanData.length() > 0)
{
public class MainActivity extends AppCompatActivity {
//The values of these variables will be fetched by the file(Where you will store data)
private String PREFERENCE_SCANINTERVAL = "scanInterval";
private String PREFERENCE_TIMESTAMP = "timestamp";
private String PREFERENCE_POWER = "power";
private String PREFERENCE_PROXIMITY = "proximity";
private String PREFERENCE_RSSI = "rssi";
private String PREFERENCE_MAJORMINOR = "majorMinor";
private String PREFERENCE_UUID = "uuid";
private String PREFERENCE_INDEX = "index";
private String PREFERENCE_LOCATION = "location";
private String PREFERENCE_REALTIME = "realTimeLog";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
String url = "http://beaconscanner.byethost33.com/beaconscanner.php";//This is the url of your server where you will be sending the data to.
//StringRequest is a class in the Volley Library.
//The constructor of this class has four parameters.
// 1 parameter is Request.Method.POST =this specifies the method type, That is post.
//2 parameter is the url you will be sending the request to.That is the server
//3 parameter is the response listener , It will listen for any response from your server . you will be able to fetch the response from the server using this.
//4 parameter is the error listener, it will listen for any error's during the connection or etc.
StringRequest request = new StringRequest(Request.Method.POST, url, new Response.Listener<String>() {
#Override
public void onResponse(String response) {
//Here you will be able to fetch the response coming from the server.
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
}
})
//This is the method we override.
{
//This is method is used to send the data to the server for post methods. This method returns all the data you want to send to server. This is how you send data using Volley.
#Override
protected Map<String, String> getParams() throws AuthFailureError {
Map<String,String> params = new HashMap<String, String>();
params.put("scanInterval",PREFERENCE_SCANINTERVAL);
params.put("timestamp",PREFERENCE_SCANINTERVAL);
params.put("power",PREFERENCE_POWER);
params.put("proximity",PREFERENCE_PROXIMITY);
params.put("rssi",PREFERENCE_RSSI);
params.put("majorMinor",PREFERENCE_MAJORMINOR);
params.put("uuid",PREFERENCE_UUID);
params.put("index",PREFERENCE_INDEX);
params.put("location",PREFERENCE_LOCATION);
params.put("realTimelog",PREFERENCE_REALTIME);
return params;
}
};//The constructor ends here.
Volley.newRequestQueue(this).add(request);// This is the main potion of this code. if you dont add this you will not be able to send the request to your server. this helps you to send it.
}
}
// Write file
fileHelper.createFile(scanData);
// Display file created message.
Toast.makeText(getBaseContext(),
"File saved to:" + getFilesDir().getAbsolutePath(),
Toast.LENGTH_SHORT).show();
scanButton.setText(MODE_STOPPED);
} else {
// We didn't get any data, so there's no point writing an empty file.
Toast.makeText(getBaseContext(),
"No data captured during scan, output file will not be created.",
Toast.LENGTH_SHORT).show();
scanButton.setText(MODE_STOPPED);
}
}

Please add your stacktrace. Also I guess that you want to send the data using the body not the params :). In that case, call the request using the following signature:
new JsonObjectRequest(Request.Method.POST, url, new JSONObject(bodyData), new Response.Listener<JSONObject>() { }

public void sendMyData(HashMap map) {
String url = "http://"....";
StringRequest request = new StringRequest(Request.Method.POST, url, new Response.Listener<String>() {
#Override
public void onResponse(String response) {
progressBar.setVisibility(View.INVISIBLE);
try {// to receive server response, in this example it's jsonArray
JSONArray jsonArray = new JSONArray(response);
//code
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
System.out.println(error);
}
}) {
#Override
public String getBodyContentType() { // if your server uses java restfull webservice , you have to override this content type
return "application/json";
}
#Override
protected Map<String, String> getParams() throws AuthFailureError {// parameters which should server receive
Map<String, String> parameters =map;
return parameters;
}
};
requestQueue.add(request);
}

JSON Download # onCreateView leaves recyclerView empty

if (isConnected()) {
Event eInstance = new Event();
theEvents = eInstance.downloadEvents(eventsNightlife, getActivity());
rAdapter = new RecyclerAdapter(theEvents);
recyclerView.setAdapter(rAdapter);
progrsBar.setVisibility(View.GONE);
....
This is part of the code that runs at "onCreateView". The method downloadEvents uses Volley to download JSON data, extract it and return a list of items (theEvents). Now when my app starts, the recycler view is empty. If I go to my home screen out of the app and then run my app again, this time the data sometimes gets downloaded.
I debugged step by step, and at first launch (i mean when the app is not just resuming), theEvents is empty, so the download didn't return or manage to return anything...
Suggestions on how to execute things before the UI has been shown to the user or what actually needs to be done to approach this task better?
Also, I use a swipeRefreshLayout and at its onRefresh method I do:
public void onRefresh() {
Event eInstance = new Event();
theEvents = eInstance.downloadEvents(eventsNightlife, getActivity());
rAdapter.notifyDataSetChanged();
swipeRefreshLayout.setRefreshing(false);
}
but it doesn't work. I also tried to
rAdapter = new RecyclerAdapter(theEvents);
rAdapter.notifyDataSetChanged();
recyclerView.swapAdapter(rAdapter, false);
still not working.
EDIT: My downloadEvents method implementing Volley:
public List<Event> downloadEvents(String urlService, Context context) {
eventsList = new ArrayList<>();
RequestQueue requestQueue = Volley.newRequestQueue(context);
JsonArrayRequest jsonArrayRequest = new JsonArrayRequest
(Request.Method.GET, urlService, null, new Response.Listener<JSONArray>() {
#Override
public void onResponse(JSONArray response) {
try {
String durationStr = null;
for (int i = 0; i < response.length(); i++) {
JSONObject eventJson = response.getJSONObject(i);
String title = eventJson.getString("EventTitle");
String body = eventJson.getString("EventBody");
String date = eventJson.getString("EventDate");
String time = eventJson.getString("EventTime");
int duration = Integer.parseInt(eventJson.getString("EventDuration"));
if (duration > 60) {
durationStr = "Duration: " + duration / 60 + " h";
} else if (duration < 60) {
durationStr = "Duration: " + duration + " m";
}
String place = eventJson.getString("EventPlace");
String organ = eventJson.getString("Organization");
Event event = new Event(title, body, date, time, durationStr, place, organ);
eventsList.add(event);
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Log.e("VOLLEY ERROR", "" + error);
}
}
);
requestQueue.add(jsonArrayRequest);
return eventsList;
}

You can use EventBus for your purpose that is a simple and truth way.
Here, i write an example for how to use EventBus with volley.
Consider that i want to download some data.
This is the class that my download methods is inside it (you can add more methods to it in the future):
Im used volley to download my data:
// Download methods is inside volley
public class MyDownloader{
public static void downloadData(){
DownloadDataEvent dlDataEvent=new DownloadDataEvent();
List<String> myResult=new ArrayList<>();
...
#Override
public void onResponse(JSONArray response) {
super.onResponse(response);
if(respone!=null){
// Do what i want with my received data
dlDataEvent.setData(response);
}
// Post my event by EventBus
EventBus.getDefault().post(dlDataEvent);
...
}
}
}
This is my event:
public class DownloadDataEvent{
private JSONArray mData;
public void setData(JSONArray data){
mData=data;
}
public JSONArray setData(){
return mData;
}
}
Now i want to use my downloadData() method inside my MainActivity:
(I called my downloadData method inside onCreate.)
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
...
// I have to register this class for EventBus subscriber:
if(!EventBus.getDefault().isRegister(this)){
EventBus.getDefault().registerSticky(this);
}
// Call my downloadData method
if(isConnected()){
MyDownloader.downloadData();
}
}
// And for receive the data through EventBus, i have to create a
// method (subscriber) in this template:
public void onEventMainThread(DownloadDataEvent downloadDataEvent){
JSONArray result=downloadDataEvent.getData();
// Do what i want with my received data
}
}
you can create more than one subscriber every where you want to use received data.
I passed JSONArray to my DownloadDataEvent that it is not good. you can deserialize your received data and pass it to your DownloadDataEvent.
I used Volley to download data
Maybe my descriptions were confusing, but EventBus is a well-known library and is very easy to use.

How to change Volley request rate

I'm making multiple requests to Amazon Web Services. I'm getting the 503 error because I'm making too many request too quickly. I want to know how to set the time-out between different requests, not the same ones. I am not looking to set the retry policy. I am also not looking to time-trigger individual requests. I want to time the interval between requests. The reason is that I am looping so quickly and making so many requests, that timing-triggering them is equivalent to submitting them all that the same time. The whole point is to space the requests out evenly.

Since you don't show how you made multiple requests, so I suggest you refer to the following sample, then try applying to your code. Hope it helps!
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final RequestQueue queue = Volley.newRequestQueue(this);
final String url = "http://google.com";
final Handler handler = new Handler();
for (int i = 0; i <= 5; i++) {
handler.postDelayed(new Runnable() {
#Override
public void run() {
StringRequest request = new StringRequest(url, new Response.Listener<String>() {
#Override
public void onResponse(String response) {
Log.i("onResponse", response);
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Log.e("onErrorResponse", error.toString());
}
});
queue.add(request);
}
}, 2000); // 2000 miliseconds
}
}

assuming you have Request object , before adding the request to the queue you can do this
request.setRetryPolicy(new DefaultRetryPolicy(5000, 5, DefaultRetryPolicy.DEFAULT_BACKOFF_MULT));
the 5000 indicates the time between each request in ms
the 5 is the number of times you want to send the request before it gives you timeout
for the sake of someone seeing this, this is how to use timers to manually seclude a task
Timer timer = new Timer();
final Handler handler = new Handler(){
#Override
public void handleMessage(Message msg) {
// Update UI here if u need
}
};
TimerTask task = new TimerTask () {
#Override
public void run () {
//send requests according to your logic here
}
};
timer.schedule(task, 0, 60000); // 60000 = 1 min

Was struggling with this too, til I got some help from another developer. Try something like this:
public class HTTP {
String getUrl;
Context context;
YTVisualizer ytv;
int numberOfCurrentRequests = 0;
public HTTP(Context context, YTVisualizer ytv){
this.context = context;
this.ytv = ytv;
}
public void get(final String url) {
numberOfCurrentRequests++;
new Thread(new Runnable() {
public void run() {
try {
Thread.sleep(250 * numberOfCurrentRequests);
} catch(InterruptedException e) {
e.printStackTrace();
}
// Instantiate the RequestQueue.
RequestQueue queue = Volley.newRequestQueue(context);
String[] parts = url.split("=");
final String key = parts[1];
// Request a string response from the provided URL.
StringRequest stringRequest = new StringRequest(Request.Method.GET, url,
new Response.Listener<String>() {
#Override
//runs in thread main
public void onResponse(String response) {
Log.i("Response", response);
String title = new String();
try {
JSONObject obj = new JSONObject(response);
Iterator<String> str = obj.keys();
String key = str.next();
title = obj.getString(key);
} catch (JSONException e) {
e.printStackTrace();
}
ytv.SetVideosFromHTTPClass(key, title, response);
numberOfCurrentRequests--;
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(context, "Error: are you connected to the internet?", Toast.LENGTH_SHORT).show();
numberOfCurrentRequests--;
}
});
// Add the request to the RequestQueue.
queue.add(stringRequest);
}
}).start();
}
}
It pauses inbetween proportional to the amount of current requests. The 1st one sleeps .25 s, the 2nd one .5s, the third one .75s, and so on. Theyre all scheduled in order.

I know this is an old question, but here is a solution written in Kotlin:
Inside your class with the RequestQueue, you can add
val throttleTimeout : Long = 100L
private val throttleQueue : ArrayBlockingQueue<Request<*>> = ArrayBlockingQueue(100);
private val throttleThread = Thread {
while(true){
val rqst = throttleQueue.take()
requestQueue?.add(rqst)
Thread.sleep(throttleTimeout)
}
}
fun <T> addToThrottledRequestQueue(request: Request<T>, tag: String){
request.tag = if (TextUtils.isEmpty(tag)) TAG else tag
throttleQueue.put(request)
}
And just make sure to start the thread in your class initialization. You can also mix this with a function to create non-throttled request and mix them together.
fun <T> addToRequestQueue(request: Request<T>, tag: String) {
request.tag = if (TextUtils.isEmpty(tag)) TAG else tag
requestQueue?.add(request)
}
The addToThrottledRequestQueue function will make sure those requests are throttled while other requests can flow freely.