viewPagerAdapter фрагмент NullPointerException на плавающей кнопке Action onClick

Question

Я создаю кнопку плавающего действия или FAB в Android, которая может решать важные действия. В нашем приложении у нас есть меню с плавающими действиями с 3 пунктами меню, каждый для сортировки результатов фильма по имени, дате и рейтингам. Я использую Java-компаратор и переопределяю метод compareTo для сравнения объектов Lhs и Rhs и возвращают результаты сравнения.

Но, когда я нажимаю одну из меню, например: сортировка результатов фильма по имени, всегда появляется ошибка java.lang.NullPointerException

, что проблема с моим кодом?

И java.lang.NullPointerException в этом коде:

Fragment mFragment = (Fragment) mAdapter.instantiateItem(viewPager, viewPager.getCurrentItem()); 

И LogCat:

04-16 02:10:22.137 3410-3410/com.qferiz.qferiztrafficinfo E/AndroidRuntime﹕ FATAL EXCEPTION: main 
    java.lang.NullPointerException 
      at com.qferiz.qferiztrafficinfo.activities.MainActivity.onClick(MainActivity.java:229) 
      at android.view.View.performClick(View.java:4336) 
      at android.view.View$PerformClick.run(View.java:17853) 
      at android.os.Handler.handleCallback(Handler.java:800) 
      at android.os.Handler.dispatchMessage(Handler.java:100) 
      at android.os.Looper.loop(Looper.java:194) 
      at android.app.ActivityThread.main(ActivityThread.java:5469) 
      at java.lang.reflect.Method.invokeNative(Native Method) 
      at java.lang.reflect.Method.invoke(Method.java:525) 
      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:857) 

я должен объявить на вершине общественного класса MainActivity:

private ViewPagerAdapter mAdapter; 

что неправильно с моим кодом? пожалуйста, помогите мне .. :(

Это мой код в MainActivity.java:

package com.qferiz.qferiztrafficinfo.activities; 

import android.content.Intent; 
import android.graphics.drawable.Drawable; 
import android.os.Bundle; 
import android.support.v4.app.Fragment; 
import android.support.v4.app.FragmentManager; 
import android.support.v4.app.FragmentStatePagerAdapter; 
import android.support.v4.view.ViewPager; 
import android.support.v4.widget.DrawerLayout; 
import android.support.v7.app.ActionBarActivity; 
import android.support.v7.widget.Toolbar; 
import android.view.Menu; 
import android.view.MenuItem; 
import android.view.View; 
import android.widget.ImageView; 
import android.widget.Toast; 

import com.oguzdev.circularfloatingactionmenu.library.FloatingActionButton; 
import com.oguzdev.circularfloatingactionmenu.library.FloatingActionMenu; 
import com.oguzdev.circularfloatingactionmenu.library.SubActionButton; 
import com.qferiz.qferiztrafficinfo.extras.SortListener; 
import com.qferiz.qferiztrafficinfo.fragments.FragmentBoxOffice; 
import com.qferiz.qferiztrafficinfo.fragments.FragmentSearch; 
import com.qferiz.qferiztrafficinfo.fragments.FragmentUpcoming; 
import com.qferiz.qferiztrafficinfo.fragments.MyFragment; 
import com.qferiz.qferiztrafficinfo.fragments.NavigationDrawerFragment; 
import com.qferiz.qferiztrafficinfo.R; 
import com.qferiz.qferiztrafficinfo.logging.L; 

import it.neokree.materialtabs.MaterialTab; 
import it.neokree.materialtabs.MaterialTabHost; 
import it.neokree.materialtabs.MaterialTabListener; 


public class MainActivity extends ActionBarActivity implements MaterialTabListener, View.OnClickListener { 

    private Toolbar toolbar; 
    private ViewPager viewPager; 
    private MaterialTabHost tabHost; 
    public static final int MOVIES_SEARCH_RESULT = 0; 
    public static final int MOVIES_HITS = 1; 
    public static final int MOVIES_UPCOMING = 2; 
    //tag associated with the FAB menu button that sorts by name 
    private static final String TAG_SORT_NAME = "sortName"; 
    //tag associated with the FAB menu button that sorts by date 
    private static final String TAG_SORT_DATE = "sortDate"; 
    //tag associated with the FAB menu button that sorts by ratings 
    private static final String TAG_SORT_RATINGS = "sortRatings"; 
    private ViewPagerAdapter mAdapter; 



    @Override 
    protected void onCreate(Bundle savedInstanceState) { 

     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 

     toolbar = (Toolbar) findViewById(R.id.app_bar); 
     setSupportActionBar(toolbar); 
     getSupportActionBar().setDisplayShowHomeEnabled(true); 

     NavigationDrawerFragment drawerFragment = (NavigationDrawerFragment) 
       getSupportFragmentManager().findFragmentById(R.id.fragment_navigation_drawer); 
     drawerFragment.setUp(R.id.fragment_navigation_drawer, (DrawerLayout) findViewById(R.id.drawer_layout), toolbar); 

     tabHost = (MaterialTabHost) findViewById(R.id.materialTabHost); 
     viewPager = (ViewPager) findViewById(R.id.viewPager); 
     //mPager.setAdapter(new MyPagerAdapter(getSupportFragmentManager())); 

     ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager()); 
     viewPager.setAdapter(adapter); 
     viewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() { 
      @Override 
      public void onPageSelected(int position) { 
       super.onPageSelected(position); 
       tabHost.setSelectedNavigationItem(position); 
      } 
     }); 

     for (int i = 0; i < adapter.getCount(); i++) { 
      // TAB TEXT 
      //tabHost.addTab(tabHost.newTab().setText(adapter.getPageTitle(i)).setTabListener(this)); 

      // TAB ICON 
      tabHost.addTab(tabHost.newTab().setIcon(adapter.getIcon(i)).setTabListener(this)); 
     } 

     // CircularFloatingActionMenu Button 
     setupFAB(); 

    } 

    private void setupFAB() { 
     // CircularFloatingActionMenu Button 
     //define the icon for the main floating action button 
     ImageView iconActionButton = new ImageView(this); 
     iconActionButton.setImageResource(R.drawable.ic_action_new); 


     // Create a button to attach the menu: 
     //set the appropriate background for the main floating action button along with its icon 
     FloatingActionButton actionButton = new FloatingActionButton.Builder(this) 
       .setContentView(iconActionButton) 
       .setBackgroundDrawable(R.drawable.selector_button_red) 
       .build(); 

     // Create menu items: 
     //define the icons for the sub action buttons 
     ImageView iconSortName = new ImageView(this); 
     iconSortName.setImageResource(R.drawable.ic_notifications_white_36dp); 
     ImageView iconSortDate = new ImageView(this); 
     iconSortDate.setImageResource(R.drawable.ic_map_white_36dp); 
     ImageView iconSortRatings = new ImageView(this); 
     iconSortRatings.setImageResource(R.drawable.ic_directions_white_36dp); 

     //set the background for all the sub buttons 
     SubActionButton.Builder itemBuilder = new SubActionButton.Builder(this); 
     itemBuilder.setBackgroundDrawable(getResources().getDrawable(R.drawable.selector_sub_button_gray)); 

     //build the sub buttons 
     SubActionButton buttonSortName = itemBuilder.setContentView(iconSortName).build(); 
     SubActionButton buttonSortDate = itemBuilder.setContentView(iconSortDate).build(); 
     SubActionButton buttonSortRatings = itemBuilder.setContentView(iconSortRatings).build(); 

     //to determine which button was clicked, set Tags on each button 
     buttonSortName.setTag(TAG_SORT_NAME); 
     buttonSortDate.setTag(TAG_SORT_DATE); 
     buttonSortRatings.setTag(TAG_SORT_RATINGS); 

     buttonSortName.setOnClickListener(this); 
     buttonSortDate.setOnClickListener(this); 
     buttonSortRatings.setOnClickListener(this); 

     //add the sub buttons to the main floating action button 
     FloatingActionMenu actionMenu = new FloatingActionMenu.Builder(this) 
       .addSubActionView(buttonSortName) 
       .addSubActionView(buttonSortDate) 
       .addSubActionView(buttonSortRatings) 
       .attachTo(actionButton) 
       .build(); 
    } 


    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     // Inflate the menu; this adds items to the action bar if it is present. 
     getMenuInflater().inflate(R.menu.menu_main, menu); 
     return true; 
    } 

    @Override 
    public boolean onOptionsItemSelected(MenuItem item) { 
     // Handle action bar item clicks here. The action bar will 
     // automatically handle clicks on the Home/Up button, so long 
     // as you specify a parent activity in AndroidManifest.xml. 
     int id = item.getItemId(); 

     //noinspection SimplifiableIfStatement 
     if (id == R.id.action_settings) { 
      Toast.makeText(this, "Anda telah meng-Klik " + item.getTitle(), Toast.LENGTH_SHORT).show(); 
      return true; 
     } 

     if (id == R.id.navigate) { 
      startActivity(new Intent(this, SubActivity.class)); 
     } 

     if (id == R.id.tabWithLibrary) { 
      startActivity(new Intent(this, ActivityUsingTabLibrary.class)); 
     } 

     if (id == R.id.vectorTestActivity) { 
      startActivity(new Intent(this, VectorTestActivity.class)); 
     } 

     return super.onOptionsItemSelected(item); 
    } 

    @Override 
    public void onTabSelected(MaterialTab materialTab) { 
     viewPager.setCurrentItem(materialTab.getPosition()); 
    } 

    @Override 
    public void onTabReselected(MaterialTab materialTab) { 

    } 

    @Override 
    public void onTabUnselected(MaterialTab materialTab) { 

    } 

    @Override 
    public void onClick(View view) { 
     Fragment mFragment = (Fragment) mAdapter.instantiateItem(viewPager, viewPager.getCurrentItem()); 

     if (mFragment != null){ 

      if (mFragment instanceof SortListener){ 

       if (view.getTag().equals(TAG_SORT_NAME)){ 
        //L.t(this,"Submenu SortName Clicked"); 
        ((SortListener) mFragment).onSortByName(); 
       } 

       if (view.getTag().equals(TAG_SORT_DATE)){ 
        //L.t(this,"Submenu SortDate Clicked"); 
        ((SortListener) mFragment).onSortByDate(); 
       } 

       if (view.getTag().equals(TAG_SORT_RATINGS)){ 
        //L.t(this,"Submenu SortRatings Clicked"); 
        ((SortListener) mFragment).onSortByRating(); 
       } 
      } 
     } 
     else { 
      L.t(this, "Error Fragment Null"); 
     } 


    } 

    private class ViewPagerAdapter extends FragmentStatePagerAdapter { 

     int icons[] = {R.drawable.ic_notifications_white_36dp, 
       R.drawable.ic_map_white_36dp, 
       R.drawable.ic_directions_white_36dp}; 

     FragmentManager fragmentManager; 

     public ViewPagerAdapter(FragmentManager fm) { 
      super(fm); 
      fragmentManager = fm; 
     } 

     @Override 
     public Fragment getItem(int num) { 
      //return MyFragment.getInstance(num); 
      Fragment fragment = null; 

      switch (num){ 
       case MOVIES_SEARCH_RESULT: 
        fragment = FragmentSearch.newInstance("", ""); 
        break; 
       case MOVIES_HITS: 
        fragment = FragmentBoxOffice.newInstance("", ""); 
        break; 
       case MOVIES_UPCOMING: 
        fragment = FragmentUpcoming.newInstance("", ""); 
        break; 
      } 
      return fragment; 
     } 

     @Override 
     public int getCount() { 
      return 3; // Jumlah TAB 
     } 

     @Override 
     public CharSequence getPageTitle(int position) { 
      return getResources().getStringArray(R.array.tabs)[position]; 
     } 

     private Drawable getIcon(int position) { 
      return getResources().getDrawable(icons[position]); 
     } 
    } 

} 

Код MovieSorter.java:

package com.qferiz.qferiztrafficinfo.extras; 

import java.util.ArrayList; 
import java.util.Collections; 
import java.util.Comparator; 

/** 
* Created by Qferiz on 15/04/2015. 
*/ 
public class MovieSorter { 
    public void sortMoviesByName(ArrayList<Movie> movies){ 
     Collections.sort(movies, new Comparator<Movie>() { 
      @Override 
      public int compare(Movie lhs, Movie rhs) { 
       return lhs.getTitle().compareTo(rhs.getTitle()); 
      } 
     }); 
    } 

    public void sortMoviesByDate(ArrayList<Movie> movies){ 
     Collections.sort(movies, new Comparator<Movie>() { 
      @Override 
      public int compare(Movie lhs, Movie rhs) { 
       return lhs.getReleaseDateTheater().compareTo(rhs.getReleaseDateTheater()); 
      } 
     }); 
    } 

    public void sortMoviesByRating(ArrayList<Movie> movies){ 
     Collections.sort(movies, new Comparator<Movie>() { 
      @Override 
      public int compare(Movie lhs, Movie rhs) { 
       //return lhs.getReleaseDateTheater().compareTo(rhs.getReleaseDateTheater()); 
       int ratingLhs = lhs.getAudienceScore(); 
       int ratingRhs = rhs.getAudienceScore(); 
       if (ratingLhs < ratingRhs){ 
        return 1; 
       } 
       else if (ratingLhs > ratingRhs){ 
        return -1; 
       } 
       else { 
        return 0; 
       } 
      } 
     }); 
    } 


} 

Некоторые коды FragmentBoxOffice.java, методы:

@Override 
    public void onSortByName() { 
     //L.t(getActivity(),"Sort name Box Office"); 
     movieSorter.sortMoviesByName(listMovies); 
     adapterBoxOffice.notifyDataSetChanged(); 

    } 

    @Override 
    public void onSortByDate() { 
     //L.t(getActivity(),"Sort Date Box Office"); 
     movieSorter.sortMoviesByDate(listMovies); 
     adapterBoxOffice.notifyDataSetChanged(); 

    } 

    @Override 
    public void onSortByRating() { 
     //L.t(getActivity(),"Sort Rating Box Office"); 
     movieSorter.sortMoviesByRating(listMovies); 
     adapterBoxOffice.notifyDataSetChanged(); 

    } 

Это полный код в FragmentBoxOffice.java:

package com.qferiz.qferiztrafficinfo.fragments; 


import android.os.Bundle; 
import android.support.v4.app.Fragment; 
import android.support.v7.widget.LinearLayoutManager; 
import android.support.v7.widget.RecyclerView; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.TextView; 

import com.android.volley.AuthFailureError; 
import com.android.volley.NetworkError; 
import com.android.volley.NoConnectionError; 
import com.android.volley.ParseError; 
import com.android.volley.Request; 
import com.android.volley.RequestQueue; 
import com.android.volley.Response; 
import com.android.volley.ServerError; 
import com.android.volley.TimeoutError; 
import com.android.volley.VolleyError; 
import com.android.volley.toolbox.ImageLoader; 
import com.android.volley.toolbox.JsonObjectRequest; 
import com.qferiz.qferiztrafficinfo.R; 
import com.qferiz.qferiztrafficinfo.adapters.AdapterBoxOffice; 
import com.qferiz.qferiztrafficinfo.extras.Constants; 
import com.qferiz.qferiztrafficinfo.extras.Movie; 
import com.qferiz.qferiztrafficinfo.extras.MovieSorter; 
import com.qferiz.qferiztrafficinfo.extras.MyApplication; 
import com.qferiz.qferiztrafficinfo.extras.SortListener; 
import com.qferiz.qferiztrafficinfo.logging.L; 
import com.qferiz.qferiztrafficinfo.network.VolleySingleton; 
import static com.qferiz.qferiztrafficinfo.extras.UrlEndpoints.*; 
import static com.qferiz.qferiztrafficinfo.extras.Keys.EndpointBoxOffice.*; 
import static com.qferiz.qferiztrafficinfo.extras.Constants.*; 

import org.json.JSONArray; 
import org.json.JSONException; 
import org.json.JSONObject; 

import java.text.DateFormat; 
import java.text.ParseException; 
import java.text.SimpleDateFormat; 
import java.util.ArrayList; 
import java.util.Date; 

/** 
* A simple {@link Fragment} subclass. 
* Use the {@link FragmentBoxOffice#newInstance} factory method to 
* create an instance of this fragment. 
*/ 
public class FragmentBoxOffice extends Fragment implements SortListener { 
    // TODO: Rename parameter arguments, choose names that match 
    // the fragment initialization parameters, e.g. ARG_ITEM_NUMBER 
    private static final String ARG_PARAM1 = "param1"; 
    private static final String ARG_PARAM2 = "param2"; 

    public static final String URL_ROTTEN_TOMATOES_BOX_OFFICE = 
      "http://api.rottentomatoes.com/api/public/v1.0/lists/movies/box_office.json"; 

    // TODO: Rename and change types of parameters 
    private String mParam1; 
    private String mParam2; 
    private VolleySingleton volleySingleton; 
    private ImageLoader imageLoader; 
    private RequestQueue requestQueue; 
    private ArrayList<Movie> listMovies = new ArrayList<>(); 
    private DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd"); 
    private RecyclerView listMovieHits; 
    private AdapterBoxOffice adapterBoxOffice; 
    private TextView textVolleyError; 
    private MovieSorter movieSorter; 


    /** 
    * Use this factory method to create a new instance of 
    * this fragment using the provided parameters. 
    * 
    * @param param1 Parameter 1. 
    * @param param2 Parameter 2. 
    * @return A new instance of fragment FragmentBoxOffice. 
    */ 
    // TODO: Rename and change types and number of parameters 
    public static FragmentBoxOffice newInstance(String param1, String param2) { 
     FragmentBoxOffice fragment = new FragmentBoxOffice(); 
     Bundle args = new Bundle(); 
     args.putString(ARG_PARAM1, param1); 
     args.putString(ARG_PARAM2, param2); 
     fragment.setArguments(args); 
     return fragment; 
    } 

    public static String getRequestUrl(int limit){ 
     //return URL_ROTTEN_TOMATOES_BOX_OFFICE+"?apikey="+ MyApplication.API_KEY_ROTTEN_TOMATOES+"&limit="+limit; 
     return URL_BOX_OFFICE 
       + URL_CHAR_QUESTION 
       + URL_PARAM_API_KEY 
       + MyApplication.API_KEY_ROTTEN_TOMATOES 
       + URL_CHAR_AMEPERSAND 
       + URL_PARAM_LIMIT + limit; 

    } 

    public FragmentBoxOffice() { 
     // Required empty public constructor 
    } 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     if (getArguments() != null) { 
      mParam1 = getArguments().getString(ARG_PARAM1); 
      mParam2 = getArguments().getString(ARG_PARAM2); 
     } 

     volleySingleton = VolleySingleton.getInstance(); 
     requestQueue = volleySingleton.getRequestQueue(); 
     sendJsonRequest(); 

    } 

    private void sendJsonRequest() { 
     JsonObjectRequest request = new JsonObjectRequest(Request.Method.GET, 
       getRequestUrl(30), 
       (String)null, 
       new Response.Listener<JSONObject>() { 
        @Override 
        public void onResponse(JSONObject response) { 
         //L.t(getActivity(), response.toString()); 
         textVolleyError.setVisibility(View.GONE); 
         listMovies = parseJSONResponse(response); 
         adapterBoxOffice.setMovieList(listMovies); 

        } 
       }, new Response.ErrorListener() { 
      @Override 
      public void onErrorResponse(VolleyError error) { 
       //L.t(getActivity(), error.getMessage() + ""); 
       handleVolleyError(error); 

      } 
     }); 

     requestQueue.add(request); 
    } 

    private void handleVolleyError(VolleyError error) { 
     textVolleyError.setVisibility(View.VISIBLE); 
     if (error instanceof TimeoutError || error instanceof NoConnectionError){ 
      textVolleyError.setText(R.string.error_timeout); 

     } else if (error instanceof AuthFailureError){ 
      //TODO: 
      textVolleyError.setText(R.string.error_auth_failure); 

     } else if (error instanceof ServerError){ 
      //TODO: 
      textVolleyError.setText(R.string.error_auth_failure); 

     } else if (error instanceof NetworkError){ 
      //TODO: 
      textVolleyError.setText(R.string.error_network); 

     } else if (error instanceof ParseError){ 
      //TODO: 
      textVolleyError.setText(R.string.error_parser); 

     } 
    } 

    private ArrayList<Movie> parseJSONResponse(JSONObject response) { 
     ArrayList<Movie> listMovies = new ArrayList<>(); 
     if (response != null && response.length() > 0){ 

      try { 

       JSONArray arrayMovies = response.getJSONArray(KEY_MOVIES); 
       for (int i = 0; i < arrayMovies.length(); i++){ 
        long id = -1; 
        String title = Constants.NA; 
        String releaseDates = Constants.NA; 
        int audienceScore = -1; 
        String synopsis = Constants.NA; 
        String urlThumbnail = Constants.NA; 

        JSONObject currentMovies = arrayMovies.getJSONObject(i); 

        // get the id of the current movie 
        if (currentMovies.has(KEY_ID) && !currentMovies.isNull(KEY_ID)){ 
         id = currentMovies.getLong(KEY_ID); 
        } 


        // get the title of the current movie 
        if (currentMovies.has(KEY_TITLE) && !currentMovies.isNull(KEY_TITLE)) { 
         title = currentMovies.getString(KEY_TITLE); 
        } 

        // get the release date of the current movie 
        if (currentMovies.has(KEY_RELEASE_DATES) && !currentMovies.isNull(KEY_RELEASE_DATES)) { 
         JSONObject objectReleaseDates = currentMovies.getJSONObject(KEY_RELEASE_DATES); 

         if (objectReleaseDates !=null && objectReleaseDates.has(KEY_THEATER) 
           && !objectReleaseDates.isNull(KEY_THEATER)) { 
          releaseDates = objectReleaseDates.getString(KEY_THEATER); 
         } 
        } 

        // get the audience score for the current movie 
        JSONObject objectRatings = currentMovies.getJSONObject(KEY_RATINGS); 

        if (objectRatings.has(KEY_AUDIENCE_SCORE) && !currentMovies.isNull(KEY_RATINGS)){ 
         if (objectRatings != null && objectRatings.has(KEY_AUDIENCE_SCORE) 
           && !objectRatings.isNull(KEY_AUDIENCE_SCORE)){ 
          audienceScore = objectRatings.getInt(KEY_AUDIENCE_SCORE); 
         } 
        } 

        // get the synopsis for the current movie 
        if (currentMovies.has(KEY_SYNOPSIS) && !currentMovies.isNull(KEY_SYNOPSIS)) { 
         synopsis = currentMovies.getString(KEY_SYNOPSIS); 
        } 

        // get the posters & thumbnail for the current movie 
        if (currentMovies.has(KEY_POSTERS) && !currentMovies.isNull(KEY_POSTERS)) { 
         JSONObject objectPosters = currentMovies.getJSONObject(KEY_POSTERS); 
         if (objectPosters != null && objectPosters.has(KEY_THUMBNAIL) 
           && !objectPosters.isNull(KEY_THUMBNAIL)) { 
          urlThumbnail = objectPosters.getString(KEY_THUMBNAIL); 
         } 
        } 

        Movie movie = new Movie(); 
        movie.setId(id); 
        movie.setTitle(title); 
        Date date = null; 

        try { 
          date = dateFormat.parse(releaseDates); 
        }catch (ParseException e){ 

        } 

        movie.setReleaseDateTheater(date); 
        movie.setAudienceScore(audienceScore); 
        movie.setSynopsis(synopsis); 
        movie.setUrlThumbnail(urlThumbnail); 

        if (id != -1 && !title.equals(Constants.NA)){ 
         listMovies.add(movie); 
        } 
       } 

       //L.T(getActivity(), listMovies.toString()); 

      } catch (JSONException e){ 

      } 

      //L.t(getActivity(), listMovies.size() + " rows fetched"); 
     } 

     L.t(getActivity(), listMovies.size() + " rows fetched"); 
     return listMovies; 

    } 

    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
          Bundle savedInstanceState) { 

     // Inflate the layout for this fragment 
     View view = inflater.inflate(R.layout.fragment_box_office, container, false); 
     textVolleyError = (TextView) view.findViewById(R.id.textVolleyError); 
     listMovieHits = (RecyclerView) view.findViewById(R.id.listMoviesHits); 
     listMovieHits.setLayoutManager(new LinearLayoutManager(getActivity())); 
     adapterBoxOffice = new AdapterBoxOffice(getActivity()); 
     listMovieHits.setAdapter(adapterBoxOffice); 
     sendJsonRequest(); 

     return view; 

     //return inflater.inflate(R.layout.fragment_box_office, container, false); 
    } 


    @Override 
    public void onSortByName() { 
     //L.t(getActivity(),"Sort name Box Office"); 
     movieSorter.sortMoviesByName(listMovies); 
     adapterBoxOffice.notifyDataSetChanged(); 

    } 

    @Override 
    public void onSortByDate() { 
     //L.t(getActivity(),"Sort Date Box Office"); 
     movieSorter.sortMoviesByDate(listMovies); 
     adapterBoxOffice.notifyDataSetChanged(); 

    } 

    @Override 
    public void onSortByRating() { 
     //L.t(getActivity(),"Sort Rating Box Office"); 
     movieSorter.sortMoviesByRating(listMovies); 
     adapterBoxOffice.notifyDataSetChanged(); 

    } 
} 

Заранее спасибо ..

Answer 1

В MainActivity.java линии 229 изменения:

Fragment mFragment = (Fragment) mAdapter.instantiateItem(viewPager, viewPager.getCurrentItem()); 

To:

Fragment mFragment = (Fragment) adapter.instantiateItem(viewPager, viewPager.getCurrentItem()); 

И он должен работать правильно.