More than 1 different addresses and only one list

Question

I use webservices in my application. Mostly my application displays wordpress site messages. The user can also add bookmarks to messages. I keep all records in columns in sqlite with mailing URLs. Now the problem is that I have many different URLs. And I want to show the contents of this URL in One ListView .

Also the json structure of all these urls is the same.

I looked at another issue related to this problem, but it doesn’t help much.

Let me show you how much I have tried so far.

here is the code this is BookmarkActivity code

 ArrayList<HashMap<String,String>> allData; String[] urlarray; @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= new String[]{url}; } for(int i=0; i <urlarray.length; i++){ MyAsyncTask task = new MyAsyncTask(i); task.execute(); } } private class MyAsyncTask extends AsyncTask<Object,Void,String>{ int urlNumber; HttpURLConnection connection=null; BufferedReader reader=null; public MyAsyncTask (int number){ this.urlNumber=number; } @Override protected String doInBackground(Object... params) { try { URL url = new URL(urlarray[urlNumber]); connection= (HttpURLConnection) url.openConnection(); connection.connect(); StringBuffer buffer = new StringBuffer(); String line = ""; while ((line = reader.readLine()) != null) { buffer.append(line); } String json = buffer.toString(); return json; } catch (MalformedURLException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } return null; } @Override protected void onPostExecute(String s) { super.onPostExecute(s); //Log.d("TAG",s); } } 

here is json. (this is not the same json, but I'm sure that every url will have the same json structure)

 { "status": "ok", "count": 1, "count_total": 1, "pages": 1, "posts": [ { "id": 1, "type": "post", "slug": "hello-world", "url": "http:\/\/localhost\/wordpress\/?p=1", "title": "Hello world!", "title_plain": "Hello world!", "content": "<p>Welcome to WordPress. This is your first post. Edit or delete it, then start blogging!<\/p>\n", "excerpt": "Welcome to WordPress. This is your first post. Edit or delete it, then start blogging!\n", "date": "2009-11-11 12:50:19", "modified": "2009-11-11 12:50:19", "categories": [], "tags": [], "author": { "id": 1, "slug": "admin", "name": "admin", "first_name": "", "last_name": "", "nickname": "", "url": "", "description": "" }, "comments": [ { "id": 1, "name": "Mr WordPress", "url": "http:\/\/wordpress.org\/", "date": "2009-11-11 12:50:19", "content": "<p>Hi, this is a comment.<br \/>To delete a comment, just log in and view the post comments. There you will have the option to edit or delete them.<\/p>\n", "parent": 0 } ], "comment_count": 1, "comment_status": "open" } ] } 

Can someone help me with this. How do I deal with this situation?

Answer 1

try this ... Actually in this code I use the Volley library for network operations. First, create the Application class in your application to avoid creating a new instance of the 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 the dependencies

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

In the manifest file, add this permission to access the network

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

the application tag refers to the name of the application class

  <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(); } 

Answer 2

You must execute each execution in the onBackground method after receiving the result of one asynchronous call. This is because the async task is running 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. } } }