Develop Reference

Android Async interface to get data obtained fron json request

i am new to Android,here is class Question bank returns list of json obj received from an api
ArrayAsyncResponse in interface containing only one method process complete ,i readed that http request is asynchronous but unable to relate
Question is model class
case 1) when there is no ArrayAsyncResponse interface exist and i return the list to main activity and print it it shows empty list but when i make call to callback.processComplete() and then return list followed by printing ,it shows data
case2 )if i pass null in this function callback.processComplete() then again returned list is empty
so what basically Interface is helping us
public class QuestionBank {
ArrayList questionArrayList = new ArrayList<>();
private String url = "https://raw.githubusercontent.com/curiousily/simple-quiz/master/script/statements-data.json";
public List<Question> getQuestions(final AnswerListAsyncResponse callBack) {
JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(
Request.Method.GET,
url,
(JSONArray) null,
new Response.Listener<JSONArray>() {
#Override
public void onResponse(JSONArray response) {
for (int i = 0; i < response.length(); i++) {
try {
Question question = new Question();
question.setAnswer(response.getJSONArray(i).get(0).toString());
question.setAnswerTrue(response.getJSONArray(i).getBoolean(1));
//Add question objects to list
questionArrayList.add(question);
//Log.d("Hello", "onResponse: " + question.getAnswer());
// Log.d("JSON", "onResponse: " + response.getJSONArray(i).get(0));
//Log.d("JSON2", "onResponse: " + response.getJSONArray(i).getBoolean(1));
} catch (JSONException e) {
e.printStackTrace();
}
}
if (null != callBack) callBack.processFinished(questionArrayList);
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
}
});
AppController.getInstance().addToRequestQueue(jsonArrayRequest);
return questionArrayList;
}
public class MainActivity extends AppCompatActivity {
private QuestionBank questionBank;
List<Question> questionList;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
questionBank=new QuestionBank();
questionList=questionBank.getQuestions(new AnswerListAsyncResponse() {
#Override
public void processFinished(ArrayList<Question> questionsArrayList) {//this function triggers when response is received from api
Log.d("inside", "processFinished: "+questionsArrayList);
}
});
Log.d("sync response", "questionLIst: "+questionList);
}
}

Sorry I can't write this in comment, but I think I can help you.
I don't understand well your question. but I think you need to get a Listener of the async in your class activity.
You can do that with EventBus, like this : https://github.com/greenrobot/EventBus

How to make multiple volley request?

I am working on chatbot which uses API to get data but when i make request in start it is working good but if i want to make another request , the result is still the old response from old request, which i have to send request again to get new result. Is there any solution ????
i tried wait() in function that have volley requests but it does not work
public String getResult(String team1,String team2,String code,Context context)
{
this.context=context;
//"https://apifootball.com/api/?action=get_H2H&firstTeam=Arsenal&secondTeam=Chelsea&APIkey=7"
String URL="https://apifootball.com/api/?action=get_H2H&firstTeam="+team1+"&secondTeam="+team2+"&APIkey=7";
//"https://apifootball.com/api/?action=get_countries&APIkey=7";
RequestQueue rq= Volley.newRequestQueue(context);
JsonObjectRequest objreq= new JsonObjectRequest(
Request.Method.GET,
URL,
null,
new Response.Listener<JSONObject>()
{
#Override
public void onResponse(JSONObject response) {
String Scores="";
// Log.e("result:",response.get(0).toString());
JSONObject obj;
// obj=response.getJSONObject("firstTeam_VS_secondTeam");
try {
JSONArray obj2 =response.getJSONArray("firstTeam_VS_secondTeam");
Log.e("obj", obj2.getJSONObject(0).getString("match_hometeam_score"));
Scores=Scores+ obj2.getJSONObject(0).getString("match_hometeam_score")+"\n"+obj2.getJSONObject(0).getString("match_awayteam_score")+"\n"+obj2.getJSONObject(0).getString("match_date");
} catch (JSONException e) {
}
String []arr = Scores.split("\n");
model = new ChatModel("First team:"+arr[0]+"\nSecond team:"+arr[1]+"\n"+"Date:"+arr[2], false);
list_chat.add(model);
//share(Scores);
}
},
new Response.ErrorListener(){
#Override
public void onErrorResponse(VolleyError error) {
Log.e("rest response",error.toString());
}
}
);
rq.add(objreq);
SharedPreferences m= PreferenceManager.getDefaultSharedPreferences(context);
final String resp=m.getString("Response","");
return resp;
}
main activity
if(result.equals("error")==true) {
APIAdapter ap = new APIAdapter();
head2Head = ap.getResult("Bristol City", "Reading", "kjkn", getApplicationContext());
finres = head2Head;
Log.e("headto",head2Head);
arr = head2Head.split("\n");
//send(arr[2],false);
// model = new ChatModel("First team:"+arr[0]+"\nSecond team:"+arr[1]+"\n"+"Date:"+arr[2], false); // user send message
/*
Team t1=new Team(3,"Bristol City");
Team t2=new Team(0,"Reading");
Long tid1=x.insertTeam(t1);
Long tid2=x.insertTeam(t2);
Match m=new Match(0,Integer.parseInt(String.valueOf(tid1)),Integer.parseInt(String.valueOf(tid2)),arr[2]);
Long mid=x.insertMatch(m);
Log.e("mid",String.valueOf(mid));
Result resul=new Result(0,Integer.parseInt(String.valueOf(mid)),x.getTeam(tid1).getTeamId(),x.getTeam(tid2).getTeamId(),Integer.parseInt(arr[0]),Integer.parseInt(arr[1]));
x.insertResult(resul);
*/}
send("First team:"+arr[0]+"\nSecond team:"+arr[1]+"\n"+"Date:"+arr[2], false);
}
send()
void send(String text,boolean sender)
{
ChatModel model = new ChatModel(text,sender); // user send message
list_chat.add(model);
CustomAdapter adapter = new CustomAdapter(list_chat,getApplicationContext());
listView.setAdapter(adapter);
//remove user message
editText.setText("");
}

I am not sure if i understand what your problem is but i will do my best to help.
Define RequestQueue outside of the function(onCreate() can be a good place), this way you don't init it every time you make a request and it can actually work as a Queue for requests.
There might be a problem with the way you handle list_chat, please post the code that you use to display it.

get string from arraylist and settext inside fragment android

I want to get string from arraylist inside oncreateview fragment but i cant figure itout since no position index has been pass. get(position) return error.
String price = arrayList.get(position).getPrice();
i need to get string price and settext for price.this is my main concern.
this values should return from arraylist.
this is response JSON array from volley using mysingleton.
Single Product Response: [{"price":"75","date":"2017-07-13 03:25:31","pk_i_id":"4"}]
this main activty fragment
public class MainActivityFragment extends Fragment {
private TextView product,price,date,title;
private String product_id;
ArrayList<ProductItem> arrayList = new ArrayList<>();
Context context;
public MainActivityFragment() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_main_activity, container, false);
product = (TextView) view.findViewById(R.id.tv1);
title = (TextView) view.findViewById(R.id.tvTitle);
price = (TextView) view.findViewById(R.id.tvPrice);
date = (TextView) view.findViewById(R.id.tvDate);
if (getArguments() != null) {
Log.i(TAG, "getArgument is not null");
product_id = getArguments().getString("product_id");
ProductBackgroundTask productBackgroundTask = new ProductBackgroundTask(this.getActivity(), product_id);
arrayList = productBackgroundTask.getList();
String price = arrayList.get(position).getPrice();
// Log.d(TAG, "price: " + price);
product.setText(product_id);
// price.setText(price);
}else {
Log.i(TAG, "getArgument is null");
}
return view;
}
}
this is task to get arraylist using volley
public class ProductBackgroundTask {
private Context context;
ArrayList<ProductItem> arrayList = new ArrayList<>();
String json_url = "phpfile.php";
private String product_id;
public ProductBackgroundTask(Context context, String product_id) {
this.context = context;
this.product_id = product_id;
}
public ArrayList<ProductItem> getList(){
StringRequest stringRequest = new StringRequest(Request.Method.POST, json_url,
new Response.Listener<String>() {
#Override
public void onResponse(String response) {
Log.d(TAG, "Single Product Response: " + response);
try {
JSONArray jsonarr = new JSONArray(response);
for (int i = 0; i < jsonarr.length(); i++) {
JSONObject jsonobj = jsonarr.getJSONObject(i);
ProductItem productItem = new ProductItem(jsonobj.getString("price"), jsonobj.getString("date"), jsonobj.getInt("pk_i_id"));
arrayList.add(productItem);
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
}
}){
#Override
protected Map<String, String> getParams() throws AuthFailureError {
Map<String,String> params = new HashMap<>();
params.put("product_id", product_id);
return params;
}
};
MySingleton.getInstance(context).addToRequestQueue(stringRequest);
return arrayList;
}
}
and this is class of array list
public class ProductItem {
private String Price,Date;
private int ProductId;
public ProductItem(String Price, String Date, int ProductId){
this.setPrice(Price);
this.setDate(Date);
this.setProductId(ProductId);
}
public int getProductId() {
return ProductId;
}
public void setProductId(int productId) {
ProductId = productId;
}
public String getPrice() {
return Price;
}
public void setPrice(String price) {
Price = price;
}
public String getDate() {
return Date;
}
public void setDate(String date) {
Date = date;
}

Clearly in your oncreate you haven’t initialized the product item and you cannot parse the complete list.You can try two to solve this
1.Pass specific item number instead of position i.e
say if you want to show 4th item then position=3
2.Or write a loop like this to parse entire arrayList like this
for(ProductItem productItem:arrayList){
String price = productItem.getPrice();
// Log.d(TAG, "price: " + price);
product.setText(product_id);
price.setText(price);
}

Mistake you're doing is that in the MainActivityFragment your trying to assign the value to the arrayList even before the data is added to the arrayList in the ProductBackgroundTask-getList. That's the reason you are getting the list null all the time. Try to use interfaces.
1.Make your MainActivityFragment implement the interface.
2.Set the value to the interface method once you get the data from the server.
3.Get the data in the MainActivityFragment inside interface method and do all the operation you're doing inside the onCreateView method.
Now your arraylist will have the data whatever you received from the server.
Below is the link for the example on interfaces if you haven't used them before. He is doing exactly as your requirement.
https://www.justinmccandless.com/post/setting-up-a-callback-function-in-android/

Allow me. The arrayList that you return from getList isn't populated at the time you call String price = arrayList.get(position).getPrice();. The server call using volley takes some time to process and that's when the onResponse gets called. This happens AFTER you've returned the arrayList which is in fact empty.
The sequence of events is as follows.
• Call to arrayList = productBackgroundTask.getList(); which returns an empty ArrayList.
• String price = arrayList.get(position).getPrice();
Now after a while..
• onResponse inside getList() gets called.
Do you now see why it's empty?
Simple Solution: • Define a simple interface ProductListener alongside ProductBackgroundTask. (With only a single abstract method onProducts).
• Instantiate it inside the Fragment's onCreateView using an anonymous class and pass it to the constructor of ProductListener to save it for later use. Do whatever you want to do with the products inside the onProducts method. (Since that will be called with the actual data)
• Call its onProducts method with the data that's parsed and fetched inside the onResponse method.
ProductBackgroundTask code:
public class ProductBackgroundTask {
private Context context;
// I removed the instance ArrayList since that can be made
// local.
// Here, we add a reference to our callback interface as we can use it later.
private ProductListener listener;
String json_url = "http://192.168.43.55/android/v1/productList.php";
private String product_id;
// Instantiate this class using an additional listener argument
// which would be a concrete implementation of our interface.
public ProductBackgroundTask(Context context, String product_id, ProductListener listener) {
this.context = context;
this.product_id = product_id;
this.listener = listener;
}
// getList should not return anything,
// so I keep the return as void.
public void getList() {
StringRequest stringRequest = new StringRequest(Request.Method.POST, json_url,
new Response.Listener<String>() {
#Override
public void onResponse(String response) {
ArrayList<ProductItem> arrayList = new ArrayList<>();
Log.d(TAG, "Single Product Response: " + response);
try {
JSONArray jsonarr = new JSONArray(response);
for (int i = 0; i < jsonarr.length(); i++) {
JSONObject jsonobj = jsonarr.getJSONObject(i);
ProductItem productItem = new ProductItem(jsonobj.getString("price"), jsonobj.getString("date"), jsonobj.getInt("pk_i_id"));
arrayList.add(productItem);
}
// Notice this line here, this is what
// calls the callback with the products.
listener.onProducts(arrayList);
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
}
}){
#Override
protected Map<String, String> getParams() throws AuthFailureError {
Map<String,String> params = new HashMap<>();
params.put("product_id", product_id);
return params;
}
};
MySingleton.getInstance(context).addToRequestQueue(stringRequest);
}
}
// Callback interface, we would need a concrete implementation
// of this and pass that to the constructor of ProductBackgroundTask.
interface ProductListener {
void onProducts(ArrayList<ProductItem> products);
}
The code inside onCreateView:
ProductBackgroundTask productBackgroundTask = new ProductBackgroundTask(this.getActivity(), product_id, new ProductListener() {
// This method will be called with the needed products.
// Give an anonymous class implementation of our interface
// right here since we won't be using it anymore.
public void onProducts(ArrayList<ProductItem> products) {
// Get the price you want.
String str = arrayList.get(0).getPrice();
// Use str wherever necessary. Use the UI thread here if you need
// to change any visible elements on the screen.
}
});
// Simply call this method to get the ball rolling.
productBackgroundTask.getList();
This is a concrete implementation of the this answer and you won't be changing much code.

Issues with Volley caching mechanism

I have a website which publishes news on daily basis.
Now, I'm sending a JsonArrayRequest to retrieve and parse the title and summary of each news published on the website. The parsed items are then used to populate RecyclerView.
The problem I'm having is the way volley implements caching .
Let's take this scenario: the app is installed, launched and the RecyclerView is populated. The user reads the news and forgets about the app
Later, the user launches the app and the items are fetched and RecyclerView is populated.
Between the first and the second launch, new news are published on the website. But in the second launch, these new items are not displayed. However, if the user manually go to app settings and clear cache of the app, and relaunch, the new items are displayed.
You get my point?
While I don't want to disable Volley caching, how do I make it to always fetch new items?
EDIT
MainActivity
public class MainActivity extends AppCompatActivity {
private final String TAG = "MainActivity";
//Creating a list of newss
private List<NewsItems> mNewsItemsList;
//Creating Views
private RecyclerView recyclerView;
private RecyclerView.Adapter adapter;
private RecyclerView.LayoutManager layoutManager;
private ProgressDialog mProgressDialog;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Log.d(TAG, "onCreate called");
//Initializing Views
recyclerView = (RecyclerView) findViewById(R.id.news_recycler);
LinearLayoutManager layoutManager = new LinearLayoutManager(this);
recyclerView.setLayoutManager(layoutManager);
//Initializing the newslist
mNewsItemsList = new ArrayList<>();
adapter = new NewsAdapter(mNewsItemsList, this);
recyclerView.setAdapter(adapter);
if (NetworkCheck.isAvailableAndConnected(this)) {
//Calling method to get data
getData();
} else {
//Codes for building Alert Dialog
alertDialogBuilder.setPositiveButton(R.string.alert_retry, new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
if (!NetworkCheck.isAvailableAndConnected(mContext)) {
alertDialogBuilder.show();
} else {
getData();
}
}
});
alertDialogBuilder.setNegativeButton(R.string.alert_cancel, new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
finish();
}
});
alertDialogBuilder.show();
}
}
//This method will get data from the web api
private void getData(){
Log.d(TAG, "getData called");
//Codes for Showing progress dialog
//Creating a json request
JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(ConfigNews.GET_URL + getNumber(),
new Response.Listener<JSONArray>() {
#Override
public void onResponse(JSONArray response) {
Log.d(TAG, "onResponse called");
//Dismissing the progress dialog
if (mProgressDialog != null) {
mProgressDialog.hide();
}
//calling method to parse json array
parseData(response);
}
},
new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
}
});
//Creating request queue
RequestQueue requestQueue = Volley.newRequestQueue(this);
//Adding request to the queue
requestQueue.add(jsonArrayRequest);
}
//This method will parse json data
private void parseData(JSONArray array){
Log.d(TAG, "Parsing array");
for(int i = 0; i<array.length(); i++) {
NewsItems newsItem = new NewsItems();
JSONObject jsonObject = null;
try {
jsonObject = array.getJSONObject(i);
newsItem.setNews_title(jsonObject.getString(ConfigNews.TAG_VIDEO_TITLE));
newsItem.setNews_body(jsonObject.getString(ConfigNews.TAG_VIDEO_BODY));
} catch (JSONException w) {
w.printStackTrace();
}
mNewsItemsList.add(newsItem);
}
adapter.notifyItemRangeChanged(0, adapter.getItemCount());
}
#Override
public void onDestroy() {
super.onDestroy();
Log.d(TAG, "onDestroy called");
if (mProgressDialog != null){
mProgressDialog.dismiss();
Log.d(TAG, "mProgress dialog dismissed");
}
}
}

Option 1) Delete Cache
before you make a call you can delete the whole cache by myDiskBasedCache.clear() or specific entries by myDiskBasedCache.remove(entryUrl)
Option 2) Custom CacheParser (in the Request)
#Override
protected Response<Bitmap> parseNetworkResponse(NetworkResponse response) {
Response<Bitmap> resp = super.parseNetworkResponse(response);
if(!resp.isSuccess()) {
return resp;
}
long now = System.currentTimeMillis();
Cache.Entry entry = resp.cacheEntry;
if(entry == null) {
entry = new Cache.Entry();
entry.data = response.data;
entry.responseHeaders = response.headers;
entry.ttl = now + 60 * 60 * 1000; //keeps cache for 1 hr
}
entry.softTtl = 0; // will always refresh
return Response.success(resp.result, entry);
}
Option 3) send requests that does not cache
myRequest.setShouldCache(false);
Option 4) use custom Cache implementation
UPDATE:
Example with your code:
//Creating a json request
JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(ConfigNews.GET_URL + getNumber(),
new Response.Listener<JSONArray>() {
#Override
public void onResponse(JSONArray response) {
Log.d(TAG, "onResponse called");
//Dismissing the progress dialog
if (mProgressDialog != null) {
mProgressDialog.hide();
}
//calling method to parse json array
parseData(response);
}
},
new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
}
}) {
#Override
protected Response<JSONArray> parseNetworkResponse(NetworkResponse response) {
Response<JSONArray> resp = super.parseNetworkResponse(response);
if(!resp.isSuccess()) {
return resp;
}
long now = System.currentTimeMillis();
Cache.Entry entry = resp.cacheEntry;
if(entry == null) {
entry = new Cache.Entry();
entry.data = response.data;
entry.responseHeaders = response.headers;
entry.ttl = now + 60 * 60 * 1000; //keeps cache for 1 hr
}
entry.softTtl = 0; // will always refresh
return Response.success(resp.result, entry);
}
};
UPDATE 2
Http protocol caching supports many ways to define how the client can cache responses and when to update them. Volley simplifies those rules to:
entry.ttl (time to live in ms) if greater than the current time then cache can be used otherwise fresh request needs to be made
and
entry.softTtl (soft time to live in ms :) if greater than the current time
cache is absolutely valid and no request to the server needs to be made, otherwise new request is still made (even if the ttl is good) and if there is a change new response will be delivered.
note that if ttl is valid and softTtl is not you can receive 2 onResponse calls

Android: Refresh ListView every minute

I've been reading all day threads regarding this issue I came up with a strategy but can't make it work
I have a listview fetching json data from a sql server
this listview already has a on swipe refresh function
I need this listview to refresh automatically only when new row was inserted in the data base.
So I wrote a php file fetching number of rows and echoing it witha 3 second refresh (on the php itself) so every time I enter the php file I get the realtime row numbers of my table.
I'm trying to build a function inside my MainActivity:
int OldNumberOfRows = data from the php file
while(true){
int newNumberOfRows = fetch data again using that php
if(both arent equal) execute refresh command.
}
Note: I got no idea how to extract the string from my asynctask to start manipulating my code with it.
That's it in general, Iv'e added the main activity , the "outer class" (FetchNumRowAsync) calling that php the swipe class and the php itself
MainActivity:
public class MainActivity extends AppCompatActivity implements SwipeRefreshLayout.OnRefreshListener {
private String TAG = MainActivity.class.getSimpleName();
private String URL = "http://troyka.esy.es/troyka/orders.php";
private SwipeRefreshLayout swipeRefreshLayout;
private ListView listView;
private SwipeListAdapter adapter;
private List<Order> orderList;
// initially offset will be 0, later will be updated while parsing the json
private int offSet = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
new FetchRowNumAsync(this).execute("http://troyka.esy.es/numberofrows.php");
listView = (ListView) findViewById(R.id.listView);
//RelativeLayout.LayoutParams layout_description = new RelativeLayout.LayoutParams(50,10);
//Rl.setLayoutParams(layout_description);
swipeRefreshLayout = (SwipeRefreshLayout) findViewById(R.id.swipe_refresh_layout);
orderList = new ArrayList<>();
adapter = new SwipeListAdapter(this, orderList);
listView.setAdapter(adapter);
swipeRefreshLayout.setOnRefreshListener(this);
/**
* Showing Swipe Refresh animation on activity create
* As animation won't start on onCreate, post runnable is used
*/
swipeRefreshLayout.post(new Runnable() {
#Override
public void run() {
swipeRefreshLayout.setRefreshing(true);
fetchOrders();
}
}
);
}
/**
* This method is called when swipe refresh is pulled down
*/
#Override
public void onRefresh() {
fetchOrders();
}
/**
* Fetching movies json by making http call
*/
private void fetchOrders() {
// showing refresh animation before making http call
swipeRefreshLayout.setRefreshing(true);
// appending offset to url
String url = URL + offSet;
// Volley's json array request object
JsonArrayRequest req = new JsonArrayRequest(url,
new Response.Listener<JSONArray>() {
#Override
public void onResponse(JSONArray response) {
Log.d(TAG, response.toString());
if (response.length() > 0) {
// looping through json and adding to order list
for (int i = 0; i < response.length(); i++) {
try {
JSONObject orderObj = response.getJSONObject(i);
int rank = orderObj.getInt("rank");
String title = orderObj.getString("title");
Order m = new Order(rank, title);
orderList.add(0, m);
// updating offset value to highest value
if (rank >= offSet)
offSet = rank;
} catch (JSONException e) {
Log.e(TAG, "JSON Parsing error: " + e.getMessage());
}
}
adapter.notifyDataSetChanged();
}
// stopping swipe refresh
swipeRefreshLayout.setRefreshing(false);
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Log.e(TAG, "Server Error: " + error.getMessage());
Toast.makeText(getApplicationContext(), error.getMessage(), Toast.LENGTH_LONG).show();
// stopping swipe refresh
swipeRefreshLayout.setRefreshing(false);
}
});
// Adding request to request queue
MyApplication.getInstance().addToRequestQueue(req);
}
}
FetchRowNumAsync:
public class FetchRowNumAsync extends AsyncTask<String, Void, String> {
private Context mContext;
public FetchRowNumAsync(Context ctx){
this.mContext = ctx;
}
protected String doInBackground(String... urls)
{
String fullString = "";
try{
URL url = new URL(urls[0]);
BufferedReader reader = new BufferedReader(new InputStreamReader(url.openStream()));
String line;
while ((line = reader.readLine()) != null) {
fullString += line;
}
reader.close();
}catch(Exception e ){
e.getMessage();
}
return fullString;
}
#Override
protected void onPostExecute(String value){
try{
((OnValueFetchedListener) mContext).onValueFetched(value);
}catch(ClassCastException e){}
}
public interface OnValueFetchedListener{
void onValueFetched(String columns);
}
}
SwipeListAdapter:
public class SwipeListAdapter extends BaseAdapter {
private Activity activity;
private LayoutInflater inflater;
private List<Order> orderList;
private String[] bgColors;
public SwipeListAdapter(Activity activity, List<Order> orderList) {
this.activity = activity;
this.orderList = orderList;
bgColors = activity.getApplicationContext().getResources().getStringArray(R.array.movie_serial_bg);
}
#Override
public int getCount() {
return orderList.size();
}
#Override
public Object getItem(int location) {
return orderList.get(location);
}
#Override
public long getItemId(int position) {
return position;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
if (inflater == null)
inflater = (LayoutInflater) activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
if (convertView == null)
convertView = inflater.inflate(R.layout.list_row, null);
TextView serial = (TextView) convertView.findViewById(R.id.serial);
TextView title = (TextView) convertView.findViewById(R.id.title);
serial.setText(String.valueOf(orderList.get(position).id));
title.setText(orderList.get(position).title);
String color = bgColors[position % bgColors.length];
serial.setBackgroundColor(Color.parseColor(color));
return convertView;
}
}
PHP
<?php
header("refresh: 3;");
$mysqli = new mysqli("irrelevant","irrelevant","irrelevant","irrelevant");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
$query = "SELECT COUNT(*) FROM orders";
$result = mysqli_query($mysqli,$query);
$rows = mysqli_fetch_row($result);
echo ($rows[0]);
$result->close();
$mysqli->close();
?>

Try this approach:
Create an endpoint in your server like the following:
//http://somesite.com/api/data/pull/check
Then, you can easily check this endpoint that returns some value like true or false depending on whether there is new data inserted into the db.
From the result you receive, you can then decide on whether to refresh your data on the phone by making another HTTP request or not. You always want to avoid making unnecessary requests to the server - remember users spend money every time they use their data plan (service).
I, like in the comments above, recommend having a column with a timestamp that you can check so that you only get the newly added data instead of everything!
I hope this gives you a simple idea on how to approach this issue! Good luck!

android app will not know when you have added/updated data in your table on the server until and unless you call script from app and fetch the data and update in your device.
only if your app has implemented these feature's
push notification- call Script every time you receive notification.
XMPP service- used for chat apps(which is not probably answer for
your question right now)
here is my suggestion for you
From server side:
create timestamp field in your table on server. update it with
current timestamp value every time you do changes(i.e update/add) in
the table.and when when that script is called send it across in json
and make your app save it in sqlite along with data.
server will compare for timestamp posted by app everytime with the
saved timestamp in the server for new data.
from client side:
for fist time timestamp from app will be 0. server will check it and
send the whole data along with the timestamp saved during changes in
table. save the data along with time stamp . second time when the
script is called App will be sending the timestamp that was last
saved.
with all this your app will not come to know still if new data is added until you call script and check. but atleast it will come to know if new data is received or not and whether to refresh ur screen
now comes script calling part from client side that is executing of assynch task, do it using handler to execute assynch class every minute
final Handler timerHandler = new Handler();
Runnable timerRunnable;
timerRunnable = new Runnable() {
#Override
public void run() {
new FetchRowNumAsync(context).execute(url);
timerHandler.postDelayed(timerRunnable, 60000); // run every minute
}
};
and unregister it in onDestroy()
#Override
public void onDestroyView() {
// TODO Auto-generated method stub
super.onDestroyView();
timerHandler.removeCallbacks(timerRunnable);
}