Данные ViewPager, потерянные при возврате с следующего экрана

Я использую ViewPager в своем приложении, и у меня есть три вкладки; Я использую ViewPager внутри фрагмента. Теперь моя проблема заключается в том, что я правильно получаю данные при загрузке приложения, но когда я перехожу на следующую страницу, а затем обратно в ViewPager, данные теряются, а вкладки не работают. Пожалуйста, помогите мне. Ниже мой код:

import com.devpoint.rprtjobs.R;

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentTabHost;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.widget.Toolbar;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.support.design.widget.TabLayout;


public class MainActivity extends Fragment {

   // Declaring Your View and Variables

   Toolbar toolbar;
   ViewPager pager;
   SwipeViewPagerAdapter adapter;
   SlidingTabLayout tabs;
   CharSequence Titles[]={"OnGoing","UpComing","Expired"};
   int Numboftabs =3;
private View rootView;

   @SuppressWarnings("deprecation")
public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        try {
            rootView = inflater.inflate(R.layout.activity_main,
                    container, false);


       adapter =  new SwipeViewPagerAdapter(getActivity().getSupportFragmentManager(),Titles,Numboftabs);

       // Assigning ViewPager View and setting the adapter
       pager = (ViewPager) rootView.findViewById(R.id.pager);
       pager.setAdapter(adapter);

       // Assiging the Sliding Tab Layout View
       tabs = (SlidingTabLayout) rootView.findViewById(R.id.tabs);
       tabs.setDistributeEvenly(true); // To make the Tabs Fixed set this true, This makes the tabs Space Evenly in Available width

       // Setting Custom Color for the Scroll bar indicator of the Tab View
       tabs.setCustomTabColorizer(new SlidingTabLayout.TabColorizer() {
           @Override
           public int getIndicatorColor(int position) {
               return getResources().getColor(R.color.tabsScrollColor);
           }
       });

       // Setting the ViewPager For the SlidingTabsLayout
       tabs.setViewPager(pager);

       pager.setOffscreenPageLimit(3);

       pager.setOnPageChangeListener(new OnPageChangeListener() {
            public void onPageScrollStateChanged(int state) {}
            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {}

            public void onPageSelected(int position) {

                if(position ==0)
                {
                    SwipeViewPagerAdapter.Pagename = "ListOnGoing";
                }
                else if(position ==1)
                {
                    SwipeViewPagerAdapter.Pagename = "ListUpComing"; 
                }
                else if(position ==2)
                {
                    SwipeViewPagerAdapter.Pagename = "ListExpired";
                }

                }
        });


   }
        catch(Exception e)
        {
            e.printStackTrace();
        }
        return rootView;

   }

}

Вот мой адаптер:

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.app.FragmentStatePagerAdapter;

/**
 * Created by Edwin on 15/02/2015.
 */
public class SwipeViewPagerAdapter extends FragmentPagerAdapter {

    CharSequence Titles[]; // This will Store the Titles of the Tabs which are Going to be passed when ViewPagerAdapter is created
    int NumbOfTabs; // Store the number of tabs, this will also be passed when the ViewPagerAdapter is created
    public static String Pagename="ListOnGoing";


    // Build a Constructor and assign the passed Values to appropriate values in the class
    public SwipeViewPagerAdapter(FragmentManager fm,CharSequence mTitles[], int mNumbOfTabsumb) {
        super(fm);

        this.Titles = mTitles;
        this.NumbOfTabs = mNumbOfTabsumb;

    }

    //This method return the fragment for the every position in the View Pager
    @Override
    public Fragment getItem(int position) {

        switch (position) {
        case 0:
            //Pagename = "ListOnGoing";
            ListOnGoing mListOnGoing = new ListOnGoing();  
            return mListOnGoing;
        case 1:
            //Pagename = "ListUpComing";
            ListUpComing mListUpComing = new ListUpComing(); 
            return mListUpComing;
        case 2:
            //Pagename = "ListExpired";
            ListExpaire mListExpaire = new ListExpaire();
            return mListExpaire;
        default:
            return null;
    }

    }

    // This method return the titles for the Tabs in the Tab Strip

    @Override
    public CharSequence getPageTitle(int position) {
        return Titles[position];
    }

    // This method return the Number of tabs for the tabs Strip

    @Override
    public int getCount() {
        return NumbOfTabs;
    }
}

И вот один из моих фрагментов:

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;

@SuppressLint("ShowToast")
public class ListOnGoing extends Fragment implements OnItemClickListener { 
    Boolean isInternetPresent = false;
    ConnectionDetector connectdetector;
    public static ListView swipelisview;
    Activity activity;
    public static ProductListAdapter productListAdapter; 
    SharedPreference sharedPreference;
    String LoggedIn;
    boolean fragmentAlreadyLoaded = false;


    @SuppressWarnings("deprecation")
    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        this.listener = (FragmentActivity) activity;
    }


    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
    }



    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {

        try {
            super.onViewCreated(view, savedInstanceState);

            swipelisview = (ListView) rootView.findViewById(R.id.list);

            View emptyView = rootView.findViewById(R.id.emptyView);
            swipelisview.setEmptyView(emptyView);

            if (savedInstanceState == null && !fragmentAlreadyLoaded) {
                fragmentAlreadyLoaded = true;
                repoObject = SplashScreen.getRepo();
                session = new SessionManager(getActivity());
                HashMap<String, String> Radious = session.getRadiousName();
                Radiosname = Radious.get(SessionManager.KEY_RadiousName);
                //LoadActivity.Status="";
                GPlaces = new GetAllGooglePlaces();
                GPlaces.GetOpportunityList("", Radiosname, getActivity());
                DisPlayOppList();
            }

            productListAdapter = new ProductListAdapter(getActivity(),
                    GetAllGooglePlaces.ArrayListOngoing);
            swipelisview.setAdapter(productListAdapter);
            productListAdapter.notifyDataSetChanged();


            session = new SessionManager(getActivity());
            HashMap<String, String> Radious = session.getRadiousName();
            Radiosname = Radious.get(SessionManager.KEY_RadiousName);


            searchedit = (EditText) rootView.findViewById(R.id.searchbox);

            Button searchbtn = (Button) rootView.findViewById(R.id.searchbtn);


            searchedit = (EditText) rootView.findViewById(R.id.searchbox);

            clearbtn = (Button) rootView.findViewById(R.id.clearbtn);

            searchedit.addTextChangedListener(watch);
            clearbtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View arg0) {
            LoadActivity.Status="";
            searchedit.setText("");
            GPlaces.GetOpportunityList("", Radiosname, getActivity());

            DisPlayOppList();
            }
            });




            searchbtn.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View arg0) {

                    getActivity().runOnUiThread(new Runnable() {

                        public void run() {
                            multipleCat = "";
                            GetAllGooglePlaces.ArrayListOngoing = new CopyOnWriteArrayList<>();
                            SearchText = searchedit.getText()
                                    .toString();

                            LoadActivity.Status = "Search";

                            if (LoadActivity.isOnline) {
                                GPlaces.GetOpportunityList(SearchText, Radiosname, getActivity());

                                DisPlayOppList();
                            }

                            else {
                                List<OpportunityTable> alloffers = repoObject.roffertable
                                        .getAlloffersbySearchKeyword(SearchText);

                                if (alloffers != null) {

                                    GPlaces.FillArrayListOffline(alloffers,"OnGoing");
                                }

                            }

                        }
                    });

                }
            });



            HashMap<String, String> user = session.getLogin();
            LoggedIn = user.get(SessionManager.KEY_Login);

            if (LoggedIn == null) {
                LoggedIn = "";
            }

            connectdetector = new ConnectionDetector(getActivity());



            try {
                // Check if Internet present
                isInternetPresent = connectdetector.isConnectingToInternet();

            } catch (Exception e) {
                e.printStackTrace();            
                PostLogcatErrors ple = new PostLogcatErrors();
                ple.PostLogcatErorrs(e);
            }






            footerlayout = (LinearLayout) rootView.findViewById(R.id.footerlayout);

            footerlayout.setOnTouchListener(new OnTouchListener() {

                @Override
                public boolean onTouch(View v, MotionEvent event) {
                    swipelisview.requestDisallowInterceptTouchEvent(true);
                    return true;
                }
            });





            swipelisview.setOnItemClickListener(new OnItemClickListener() {
                public void onItemClick(AdapterView<?> arg0, View v,
                        final int position, long id) {

                    InputMethodManager imm = (InputMethodManager) getActivity()
                            .getSystemService(Context.INPUT_METHOD_SERVICE);
                    imm.hideSoftInputFromWindow(swipelisview.getWindowToken(), 0);

                    try {
                        final DetailsViewpagerFragment mDetailsViewpagerFragment = new DetailsViewpagerFragment();
                        String url;
                        if (LoadActivity.isOnline) {

                            progresdialog = new ProgressDialog(getActivity());
                            progresdialog.setMessage(Html
                                    .fromHtml("<b>Search</b><br/>Loading Details..."));
                            progresdialog.setIndeterminate(false);
                            progresdialog.setCancelable(false);
                            progresdialog.show();

                            ListDetails product = GetAllGooglePlaces.ArrayListOngoing
                                    .get(position);
                            OpportunityID = product.getOfferID();


                            url = LoadActivity.BaseUri + "SaveUserViewedOpportunities";

                            JsonObjectRequest jsObjRequest;
                            jsObjRequest = new JsonObjectRequest(
                                    Request.Method.POST, url,
                                    getSaveViewUserParams(),
                                    new Response.Listener<JSONObject>() {

                                        @Override
                                        public void onResponse(JSONObject response) {

                                            pagename = "Userplaceslist";

                                            mDetailsViewpagerFragment
                                                    .setClickList(position);
                                            FragmentManager fragment = getFragmentManager();

                                            fragment.beginTransaction()
                                                    .replace(R.id.frame_container,
                                                            mDetailsViewpagerFragment)
                                                    .commit();

                                            LoadActivity.CURRENTFRAGMENT = EnumModuleTags.SinglePlaceActivity;



                                            ModuleFragmentBackStackingClass
                                                    .AddtoStack(
                                                            mDetailsViewpagerFragment,
                                                            EnumModuleTags.SinglePlaceActivity,
                                                            getString(R.string.mainfrgment_rprt));
                                            LoadActivity.updateActionbarMenu();

                                            progresdialog.dismiss();


                                        }

                                    }, new Response.ErrorListener() {

                                        @Override
                                        public void onErrorResponse(
                                                VolleyError error) {
                                            Toast.makeText(getActivity(), "False",
                                                    Toast.LENGTH_LONG).show();  
                                            progresdialog.dismiss();
                                        }
                                    });

                            AppController.getInstance().addToRequestQueue(
                                    jsObjRequest);
                        } else { 

                            mDetailsViewpagerFragment.setClickList(position);
                            FragmentManager fragment = getFragmentManager();

                            fragment.beginTransaction()
                                    .replace(R.id.frame_container,
                                            mDetailsViewpagerFragment).commit();

                            LoadActivity.CURRENTFRAGMENT = EnumModuleTags.SinglePlaceActivity;
                            ModuleFragmentBackStackingClass.AddtoStack(
                                    mDetailsViewpagerFragment,
                                    EnumModuleTags.SinglePlaceActivity,
                                    getString(R.string.mainfrgment_rprt));
                        }

                    } catch (Exception e) {
                        e.printStackTrace();            
                        PostLogcatErrors ple = new PostLogcatErrors();
                        ple.PostLogcatErorrs(e);
                    } 

                }

                private JSONObject getSaveViewUserParams() {

                    JSONObject params = new JSONObject();

                    HashMap<String, String> UserId = session.getUserID(); 
                    String UserIdVal = UserId.get(SessionManager.KEY_UserID);



                    if (!(UserIdVal == null)) {
                        UserIdVal = UserId.get(SessionManager.KEY_UserID);
                    } else {
                        UserIdVal = "0";
                    }

                    try {
                        params.put("UserId", UserIdVal);
                        params.put("OpportunityID", OpportunityID);
                        params.put("UserViewedID", 0);
                        params.put("Shortlisted", true);
                        params.put("KeyValue",  null); 
                    } catch (JSONException e) {
                        e.printStackTrace();            
                        PostLogcatErrors ple = new PostLogcatErrors();
                        ple.PostLogcatErorrs(e);
                    }

                    return params;
                }

            });

            // Click The FavoritesItem on LongPress
            swipelisview.setOnItemLongClickListener(new OnItemLongClickListener() {

                @Override
                public boolean onItemLongClick(AdapterView<?> parent, View view,
                        int position, long id) {

                    InputMethodManager imm;
                    imm = (InputMethodManager) getActivity()
                            .getSystemService(Context.INPUT_METHOD_SERVICE);
                    imm.hideSoftInputFromWindow(swipelisview.getWindowToken(), 0);

                    try {
                        ImageView button;
                        button = (ImageView) view
                                .findViewById(R.id.fav_checkbox);

                        String tag = button.getTag().toString();
                        if (tag.equals(getString(R.string.grey_favcolor))) {
                            sharedPreference.addFavorite(activity,
                                    GetAllGooglePlaces.ArrayListOngoing.get(position));
                            button.setTag(getString(R.string.red_favcolor));
                            button.setImageResource(R.drawable.checked);
                        } else if (tag.equals(getString(R.string.red_favcolor))){
                            sharedPreference.removeFavorite(activity,
                                    GetAllGooglePlaces.ArrayListOngoing.get(position));
                            button.setTag(getString(R.string.grey_favcolor));
                            button.setImageResource(R.drawable.unchecked);
                        }

                        return true;
                    } catch (NotFoundException e) {
                        e.printStackTrace();            
                        PostLogcatErrors ple = new PostLogcatErrors();
                        ple.PostLogcatErorrs(e);
                        Toast.makeText(getActivity(), e.getMessage(),
                                Toast.LENGTH_LONG).show();
                        e.printStackTrace();
                    }
                    return true;
                }

            });




            // Code placed here will be executed even when the fragment comes from
            // backstack
        } catch (Exception e) {
            e.printStackTrace();            
            PostLogcatErrors ple = new PostLogcatErrors();
            ple.PostLogcatErorrs(e);
        }
    }

    // String APIkey ="AIzaSyCAekTB0o1MuSYvUb-8HTZxhlJHE8yBUfI";
    @Override
    public void onCreate(Bundle savedInstanceState) {
        try {
            super.onCreate(savedInstanceState);
            activity = getActivity();
            sharedPreference = new SharedPreference();
            //setRetainInstance(true);
        } catch (Exception e) {
            e.printStackTrace();            
            PostLogcatErrors ple = new PostLogcatErrors();
            ple.PostLogcatErorrs(e);
        }
    }

    @SuppressWarnings("static-access")
    @SuppressLint({ "CutPasteId", "ClickableViewAccessibility" })
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        try {
            //setRetainInstance(true);

            try
            {
                 Tracker t = ((Analytics) getActivity().getApplication()).getTracker(
                            TrackerName.APP_TRACKER);

            t.setScreenName("UserPlaces Listview");

            t.send(new HitBuilders.AppViewBuilder().build());
            }
            catch(Exception e)
            {
            Toast.makeText(getActivity().getApplication(), "Error"+e.getMessage(), 1).show();  
            }


             rootView = inflater.inflate(R.layout.user_places_listview, container,
                    false);

             swipelisview = (ListView) rootView.findViewById(R.id.list);

                View emptyView = rootView.findViewById(R.id.emptyView);
                swipelisview.setEmptyView(emptyView);


            return rootView;
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return rootView;
    }


    TextWatcher watch = new TextWatcher(){

        @Override
        public void afterTextChanged(Editable arg0) {

        }

        @Override
        public void beforeTextChanged(CharSequence arg0, int arg1, int arg2,
        int arg3) {

        }

        @Override
        public void onTextChanged(CharSequence s, int a, int b, int c) {

        if(c == 0){
        clearbtn.setVisibility(View.GONE);
        }
        else {
        clearbtn.setVisibility(View.VISIBLE);
        }
        }};


    protected void LoadSearchPlaces(String searchparam) {
        try {
            if (LoadActivity.isOnline) {

                JsonArrayRequest movieReq = new JsonArrayRequest("http://192.168.2.10/RPRT.WebApi/api/RPRT/" + "SearchPlaces/"+searchparam,
                        new Response.Listener<JSONArray>() {
                                @Override
                                public void onResponse(JSONArray response) { 
                                    List<HashMap<String, String>> aList = new ArrayList<>();
                                    for (int i = 0; i < response.length(); i++) {
                                        JSONObject json_data;
                                        try {
                                            json_data = response.getJSONObject(i);
                                            HashMap<String, String> hm = new HashMap<>();
                                            hm.put("Address", json_data.getString("Address"));
                                            hm.put("City", json_data.getString("City"));
                                            hm.put("Latitude", json_data.getString("Latitude"));
                                            hm.put("Longitude", json_data.getString("Longitude"));
                                            aList.add(hm);
                                        } catch (JSONException e) {
                                            // TODO Auto-generated catch block
                                            e.printStackTrace(); 
                                        }

                                    }
                                    String[] from = { "Address"} ;
                                    int[] to = { R.id.tv };
                                    SimpleAdapter adapterId = new SimpleAdapter(getActivity(), aList,
                                            R.layout.user_places_dropdown_listitem, from, to);

                                    //final AutoCompleteTextView autoCompView = (AutoCompleteTextView) rootView.findViewById(R.id.autoCompleteTextView);

                                    autoCompView.setAdapter(adapterId);

                                    autoCompView.setThreshold(1);

                                    // Pname.setThreshold(1);

                                    autoCompView.setOnItemClickListener(new AdapterView.OnItemClickListener() {

                                        @SuppressWarnings("unchecked")
                                        @Override
                                        public void onItemClick(AdapterView<?> parent, View view,
                                                int position, long id) {
                                            HashMap<String, String> hm = (HashMap<String, String>) parent
                                                    .getAdapter().getItem(position);

                                            autoCompView.setText(hm.get("Address"));
                                            SplashScreen.nwLocation.setLatitude(Double.parseDouble(hm.get("Latitude")));
                                            SplashScreen.nwLocation.setLongitude(Double.parseDouble(hm.get("Longitude")));

                                             HashMap<String, String> Radious = session.getRadiousName();
                                                final String Radiosname;
                                                Radiosname = Radious.get(SessionManager.KEY_RadiousName);

                                                multipleCat="";
                                            ProgressDialog progresdialog = new ProgressDialog(getActivity());
                                            progresdialog.setMessage(Html
                                                    .fromHtml("<b>Search</b><br/>Loading Details..."));
                                            progresdialog.setIndeterminate(false);
                                            progresdialog.setCancelable(false);
                                            //progresdialog.show();
                                            LoadActivity.Status="";
                                            GPlaces.GetOpportunityList(SearchText, Radiosname, getActivity());

                                            DisPlayOppList();

                                            searchdialog.cancel();


                                        }

                                    }); 


                            }
                        },
                        new com.android.volley.Response.ErrorListener() {
                            @Override
                            public void onErrorResponse(
                                    VolleyError error) {

                            }

                        });

                AppController.getInstance().addToRequestQueue(movieReq);


            } 

        } catch (Exception e) {
            e.printStackTrace();
        }
    }




    private void DisPlayOppList() {
        try {

            pdialog = new ProgressDialog(getActivity());
            pdialog.setMessage(Html.fromHtml("<b>Search</b><br/>Loading Details..."));
            pdialog.setIndeterminate(false);
            pdialog.setCancelable(false);


                if(LoadActivity.Status.equals("Slidemenulist"))  
                {
                    int CategoryId = 0;
                    switch (CopyOfListOnGoing.multipleCat) {
                        case "Books":
                            CategoryId = 1;
                            break;
                        case "BeautyandFashion":
                            CategoryId = 2; 
                            break;
                        case "Electronic":
                            CategoryId = 3;
                            break;
                        case "Food":
                            CategoryId = 4;  
                            break;
                        case "HomeService":
                            CategoryId = 5;
                            break;
                        case "Jobs":
                            CategoryId = 6;
                            break;
                        case "RealEstate":
                            CategoryId = 7;
                            break;
                        case "Vehicles":
                            CategoryId = 8;
                            break;
                    }

                    List<OpportunityTable> alloffers = repoObject.roffertable
                            .getAllCatOpp(CategoryId , Radiosname); 

                    if (alloffers != null) {

                        GPlaces.FillArrayListOffline(alloffers,"OnGoing");
                    }

                } else {
                    List<OpportunityTable> alloffers = repoObject.roffertable
                            .getAlloffers(Integer.parseInt(Radiosname));

                    if (alloffers != null) {

                        GPlaces.FillArrayListOffline(alloffers,"OnGoing");
                    }
                }
        }

        catch (Exception e) {
            e.printStackTrace();            
            PostLogcatErrors ple = new PostLogcatErrors();  
            ple.PostLogcatErorrs(e);
        }
    }


    public void onItemClick(AdapterView<?> adapterView, View view, int position, long id) {

        InputMethodManager imm = (InputMethodManager) getActivity().getSystemService(Context.INPUT_METHOD_SERVICE);
        imm.hideSoftInputFromWindow(getActivity().getCurrentFocus().getWindowToken(), 0);

        multipleCat = "";
        DisPlayOppList(); 

    }


    /* @Override
      public void onResume() {
         Log.e("DEBUG", "onResume of Userplace ListView");
         super.onResume();
      }*/

      @Override
      public void onPause() {
        Log.e("DEBUG", "OnPause of Userplace ListView");
        super.onPause();
      }




}

Остальные фрагменты выглядят одинаково. Пожалуйста, помогите мне.

Ответы

  /**
   The [android.support.v4.view.PagerAdapter] that will provide
   fragments for each of the sections. We use a
   {@link FragmentPagerAdapter} derivative, which will keep every
   loaded fragment in memory. If this becomes too memory intensive, it
   may be best to switch to a
   [android.support.v4.app.FragmentStatePagerAdapter].
  */

pager = (ViewPager) rootView.findViewById(R.id.pager);
pager.setOffscreenPageLimit(2);// no of fragments

public float getPageWidth(int position)
{
if (position == 0 || position == 2)
{
return 0.8f;
}
return 1f;
}