More than 1 different Urls and only One listview

2 comments

1. try this one…Actually in this code am using Volley Library for Network Operations.
   First of all create Application class in your Application to avoid creating new instance of Volley library for network operations.

   public class ApplicationController extends Application {
   
   public static final String TAG = ApplicationController.class
           .getSimpleName();
   
   private RequestQueue mRequestQueue;
   private ImageLoader mImageLoader;
   
   private static ApplicationController mInstance;
   
   @Override
   public void onCreate() {
       super.onCreate();
       mInstance = this;
   }
   
   public static synchronized ApplicationController getInstance() {
       return mInstance;
   }
   
   public RequestQueue getRequestQueue() {
       if (mRequestQueue == null) {
           mRequestQueue = Volley.newRequestQueue(getApplicationContext());
       }
   
       return mRequestQueue;
   }
   
    //This function  request the volley library to process with tag
     //where <T> a generic method with an unbound type variable T.You can pass any datatype to functions.for more info About generic method.go through this link:http://docs.oracle.com/javase/tutorial/extra/generics/methods.html
   public <T> void addToRequestQueue(Request<T> req, String tag) {
       // set the default tag if tag is empty
       req.setTag(TextUtils.isEmpty(tag) ? TAG : tag);
       getRequestQueue().add(req);
   }
    //This function  request the volley library to process with tag
   public <T> void addToRequestQueue(Request<T> req) {
       req.setTag(TAG);
       getRequestQueue().add(req);
   }
   //This function cancel the requested Url those are all in pending
   public void cancelPendingRequests(Object tag) {
       if (mRequestQueue != null) {
           mRequestQueue.cancelAll(tag);
       }
   }
   }
   

   In app build.gradle add this line under dependencies

    compile 'com.mcxiaoke.volley:library-aar:1.0.0'
   

   In manifest file add this permission to access network

   <uses-permission android:name="android.permission.INTERNET"></uses-permission>
   

   in Application tag mentioned the application class name

     <application
       android:name=".ApplicationController" 
        android:allowBackup="true"
       android:icon="@mipmap/ic_launcher"
       android:label="@string/app_name"
       android:supportsRtl="true"
       android:theme="@style/AppTheme">
        //your activity....
        </application>
   

   In Activity onCreate add this line…

       progressDialog=new ProgressDialog(MainClass.this);
       progressDialog.setMessage("Loading...");
       progressDialog.show();
      //place your code to form urlarray
       urlarray = new String[5];
      //where datas represents the arraylist to store received content from json response.if you want to show more datas add your custom object to arraylist
       datas=new ArrayList<String>();
   
        adapter= new ArrayAdapter<String>(this,
               android.R.layout.simple_list_item_1, android.R.id.text1);
       try {
           for (int i = 0; i < urlarray.length; i++) {
               final int j = i;
               String url=urlarray[i];
               JsonObjectRequest objectRequest = new JsonObjectRequest(Request.Method.GET, url, (JSONObject) null, new Response.Listener<JSONObject>() {
                   @Override
                   public void onResponse(JSONObject response) {
                       Log.e("Response is for  " + Integer.toString(j), response.toString());
           //Here i assumed received json response is same as of sample json Provided by you.
                       try{
                       JSONArray jsonArray=response.getJSONArray("posts");
                       if(jsonArray.length()>0){
                           JSONObject obj=jsonArray.getJSONObject(0);
                           String content=obj.getString("content");
                           datas.add(content);
                       }
                       if(j==urlarray.length-1) {
                           progressDialog.dismiss();
                           adapter= new ArrayAdapter<String>(MainClass.this,
                                   android.R.layout.simple_list_item_1, android.R.id.text1,datas);
                           listView.setAdapter(adapter);
                       }
                       }catch(Exception e){
                           e.printStackTrace();
                       }
                   }
               }, new Response.ErrorListener() {
                   @Override
                   public void onErrorResponse(VolleyError error) {
                       Log.e("error",error.toString());
                       if(j==urlarray.length-1) {
                           progressDialog.dismiss();
                       }
                       }
               }){
                   @Override
                   public Map<String, String> getHeaders() throws AuthFailureError {
                       HashMap<String, String> headers = new HashMap<String, String>();
                       headers.put("Content-Type", "application/json");
                       headers.put( "charset", "utf-8");
                       return headers;
                   }
               };
               objectRequest.setRetryPolicy(new DefaultRetryPolicy(5000,
                       DefaultRetryPolicy.DEFAULT_MAX_RETRIES,
                       DefaultRetryPolicy.DEFAULT_BACKOFF_MULT));
           ApplicationController.getInstance().addToRequestQueue(objectRequest, "JSON");
           }
   
       } catch (Exception e) {
           e.printStackTrace();
       }
   

2. You should be doing every execution in the onBackground method after you get the result of one asynchronous call. This is because the async task executes on a different thread.

   ArrayList<HashMap<String,String>> allData;
   Iterator iterator;
   ArrayList<String> urlarray = new ArrayList<>();
   @Override
   protected void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.activity_bookmark);
       SqliteController controller= new SqliteController(this);
   
       allData = controller.getAllData();
       for (int i=0; i<allData.size(); i++){
           String url=allData.get(i).get("link");
           urlarray.add(url);
       }
       iterator = urlarray.iterator();
       MyAsyncTask task = new MyAsyncTask();
       task.execute();
   
   }
   private class MyAsyncTask extends AsyncTask<Object,Void,ArrayList<String>>{
       int urlNumber;
       ArrayList<String> resultList  = new ArrayList<>();
       HttpURLConnection connection=null;
       BufferedReader reader=null;
       public MyAsyncTask (){
   
       }
       @Override
       protected String doInBackground(Object... params) {
           if(iterator.hasNext()) {
               try {
   
               URL url = new URL(iterator.next());
               connection= (HttpURLConnection) url.openConnection();
               connection.connect();
               StringBuffer buffer = new StringBuffer();
               String line = "";
               while ((line = reader.readLine()) != null) {
                   buffer.append(line);
               }
               String json = buffer.toString();
               resultList.add(json);
           } catch (MalformedURLException e) {
               e.printStackTrace();
           } catch (IOException e) {
               e.printStackTrace();
           }
   
           }
           return resultList;
       }
           @Override
           protected void onPostExecute(ArrayList<String> s) {
               super.onPostExecute(s);
               //Log.d("TAG",s);
               if(s.size > 0){
                 //Your listview processing here.
               }
           }
       }
   

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