RecyclerViewフラグメントが表示されない

Question

私は、recyclerviewでデータを表示するためのアプリケーションを作成しようとしています。しかし、私がそれを実行すると、メインビューは空白になります（ツールバーとナビゲーションドロワは正常に動作します）。私は細心の注意を払ってエラーを探し、類似の問題を調べましたが、これまでのところ何も働いていませんでした。 asynctasksをテストしましたが、動作しますが、情報は表示されません。

主な活動：

public class MainActivity extends AppCompatActivity { 
private DrawerLayout mDrawerLayout; 
private static ListView mDrawerList; 
private static ActionBarDrawerToggle mDrawerToggle; 
private CharSequence mDrawerTitle; 
private CharSequence mTitle; 
private static String zipCode = "<zipcode>"; 
private static String street = "<address>"; 
public static String[] officeList = null; 
public static Elements positionLinks = null; 
public static int positionSelected; 
public CardFragment currentFragment; 
public static String[] namesOfCandidates; 
public static String[] partiesOfCandidates; 
public static String[] occupationsOfCandidates; 
public static String[] candidateLinks; 
public static boolean gotCandidates = false; 

public static Context context; 
@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    context = this; 
    setContentView(R.layout.activity_main); 
    Toolbar myToolbar = (Toolbar) findViewById(R.id.my_toolbar); 
    officeList = getResources().getStringArray(R.array.offices_array); 
    new AsyncPositions().execute(); 
    mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout); 
    mDrawerList = (ListView) findViewById(R.id.left_drawer); 
    // Set the adapter for the list view 
    mDrawerList.setAdapter(new ArrayAdapter<String>(this, 
      R.layout.drawer_list_item, officeList)); 
    // Set the list's click listener 
    mDrawerList.setOnItemClickListener(new DrawerItemClickListener()); 
    mTitle = mDrawerTitle = getTitle(); 
    mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout); 
    mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout, R.string.drawer_open, R.string.drawer_close) { 

     /** Called when a drawer has settled in a completely closed state. */ 
     public void onDrawerClosed(View view) { 
      super.onDrawerClosed(view); 
      invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu() 
     } 

     /** Called when a drawer has settled in a completely open state. */ 
     public void onDrawerOpened(View drawerView) { 
      super.onDrawerOpened(drawerView); 
      invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu() 
     } 
    }; 

    // Set the drawer toggle as the DrawerListener 
    mDrawerLayout.setDrawerListener(mDrawerToggle); 
} 

@Override 
protected void onPostCreate(Bundle savedInstanceState) { 
    super.onPostCreate(savedInstanceState); 
    // Sync the toggle state after onRestoreInstanceState has occurred. 
    mDrawerToggle.syncState(); 
} 

@Override 
public void onConfigurationChanged(Configuration newConfig) { 
    super.onConfigurationChanged(newConfig); 
    mDrawerToggle.onConfigurationChanged(newConfig); 
} 

public boolean onPrepareOptionsMenu(Menu menu) { 
    // If the nav drawer is open, hide action items related to the content view 
    boolean drawerOpen = mDrawerLayout.isDrawerOpen(mDrawerList); 
    menu.findItem(R.id.action_favorite).setVisible(!drawerOpen); 
    return super.onPrepareOptionsMenu(menu); 
} 

public boolean onOptionsItemSelected(MenuItem item) { 

    if (mDrawerToggle.onOptionsItemSelected(item)) { 
     return true; 
    }else if(item.getItemId()==R.id.action_settings){ 
     Toast.makeText(this, "Settings", Toast.LENGTH_SHORT).show(); 
     // User chose the "Settings" item, show the app settings UI... 
     return true; 
    }else if(item.getItemId()==R.id.action_favorite){ 
     Toast.makeText(this, "Favorited", Toast.LENGTH_SHORT).show(); 
     // User chose the "Favorite" action, mark the current item 
     // as a favorite... 
     //remember to change this to something else - or maybe just a starred thing for elected officials 
     return true; 
    }else { 
     // If we got here, the user's action was not recognized. 
     // Invoke the superclass to handle it. 
     return super.onOptionsItemSelected(item); 
    } 

} 

public boolean onCreateOptionsMenu(Menu menu) { 
    // Inflate the menu items for use in the action bar 
    MenuInflater inflater = getMenuInflater(); 
    inflater.inflate(R.menu.action_bar_buttons, menu); 
    return super.onCreateOptionsMenu(menu); 
} 

private class DrawerItemClickListener implements ListView.OnItemClickListener { 
    @Override 
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) { 
     selectItem(position); 
    } 
} 

    /** 
    * Swaps fragments in the main content view 
    */ 
    private void selectItem(int position) { 
     positionSelected = position; 
     //try { 
      new AsyncCandidates().execute(); 
     /* } 
     catch(InterruptedException ie){ 
      ie.printStackTrace(); 
     } 
     catch(ExecutionException ee){ 
      ee.printStackTrace(); 
     }*/ 


     //change the cards to info about candidate 
     // Highlight the selected item, update the title, and close the drawer 
     mDrawerList.setItemChecked(position, true); 
     setTitle(officeList[position]); 
     mDrawerLayout.closeDrawer(mDrawerList); 
    } 

    @Override 
    public void setTitle(CharSequence title) { 
     mTitle = title; 
    } 

public String pollingPlaceInfo(){ 
    //document.getElementsByClassName("PollingPlace_polling-place-content_ucq")[0].innerText; 
    return null; 
} 

//Gets the information about the specific candidate chosen by the card view 
// requests position on drawer and candidate number (index) to pinpoint which candidate 
// returns 2d array that contains each issue as well as info about it 
public String[][] getIssues(int position, int candidate) { 
    return null; 
} 

//asynctask to pull the positions for the nav drawer 
private static class AsyncPositions extends AsyncTask<Void, Void, Void> 
{ 
    ProgressDialog pdLoading = new ProgressDialog(MainActivity.context); 
    String[] positions; 
    private String zipCode; 
    private String street; 
    private String urlString = ""; 
    private Elements positionLinks; 

    @Override 
    protected void onPreExecute() { 
     super.onPreExecute(); 
     //this method will be running on UI thread 
     pdLoading.setMessage("\tLoading..."); 
     pdLoading.setCancelable(false); 
     pdLoading.setCanceledOnTouchOutside(false); 

     pdLoading.show(); 
     zipCode = MainActivity.zipCode; 
     street = MainActivity.street; 
    } 
    @Override 
    protected Void doInBackground(Void... params) { 
     Document doc = null; 

     urlString = "http://votersedge.org/en/ca/search?zip="+zipCode+"&address="+street; 

     try { 
      //get initial landing page to find most recent election 
      doc = Jsoup.connect(urlString) 
        .userAgent("Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.87 Safari/537.36") 
        .timeout(12000) 
        .followRedirects(true) 
        .get(); 
      //get the link to the most recent election page 
      String newLink = ""; 
      boolean nullpe = false; 
      try{ 
       doc.body().getElementsByClass("MultipleElections_upcoming-elections_3C2 col-md-12").first().child(1).attr("action"); 
      } 
      catch(NullPointerException npe) { 
       newLink = "http://votersedge.org"+doc.body().getElementsByClass("MultipleElections_recent-elections_rsw col-md-12").first().child(1).attr("action"); 
       nullpe = true; 
      } 
      if(!nullpe) { 
       newLink = "http://votersedge.org" + doc.body().getElementsByClass("MultipleElections_upcoming-elections_3C2 col-md-12").first().child(1).attr("action"); 
      } 

      doc = Jsoup.connect(newLink) 
        .userAgent("Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.87 Safari/537.36") 
        .timeout(12000) 
        .followRedirects(true) 
        .get(); 
     } 
     catch(IOException ioe){ 
      ioe.printStackTrace(); 
     } 
     Elements positionHeaders = doc.getElementsByClass("ContestsList_jurisdiction-group-label_1Kt"); 
     positionLinks = doc.getElementsByClass("ContestsList_contest-link_W44"); 



     //get size of positions list for easy access 
     int sizeOfList = positionLinks.size()/2; 
     //create array that will be returned 
     positions = new String[sizeOfList]; 
     int l = 0; 
     int k=0; 
     int j=2; 
     for(int i=0; i<sizeOfList; i++){ 
      try{ 
       doc.getElementsByClass("ContestsList_accordion-content_1rY card-content").first().child(k).child(j); 
      } 
      catch(IndexOutOfBoundsException ibe){ 
       k++; 
       j=2; 
       l++; 
      } 

      try{ 
       doc.getElementsByClass("ContestsList_accordion-content_1rY card-content").first().child(k).child(j).child(0); 
      } 
      catch(IndexOutOfBoundsException ibe){ 
       j++; 
       l++; 
      } 

      while(!doc.getElementsByClass("ContestsList_accordion-content_1rY card-content").first().child(k).child(j).child(0).tagName().equals("h4")){ 
       j++; 
       l++; 
      } 
      positions[i] = positionHeaders.eq(l).text() + " " +doc.getElementsByClass("ContestsList_accordion-content_1rY card-content").first().child(k).child(j).child(0).child(0).child(1).text(); 
      j++; 
     } 
     return null; 
    } 

    @Override 
    protected void onPostExecute(Void result) { 
     super.onPostExecute(result); 

     MainActivity.officeList = positions; 
     MainActivity.mDrawerList.setAdapter(new ArrayAdapter<>(MainActivity.context, 
       R.layout.drawer_list_item, MainActivity.officeList)); 
     MainActivity.positionLinks = positionLinks; 
     pdLoading.dismiss(); 
    } 

} 
private class AsyncCandidates extends AsyncTask<Void, Void, Void> 
{ 
    ProgressDialog pdLoading = new ProgressDialog(MainActivity.context); 
    private Elements positionElements; 
    private int position; 
    private String[] namesOfCandidates; 
    private String[] partiesOfCandidates; 
    private String[] occupationsOfCandidates; 
    private String[] candidateLinks; 
    @Override 
    protected void onPreExecute() { 
     super.onPreExecute(); 
     //this method will be running on UI thread 
     pdLoading.setMessage("\tLoading..."); 
     pdLoading.setCancelable(false); 
     pdLoading.setCanceledOnTouchOutside(false); 
     pdLoading.show(); 
     positionElements = MainActivity.positionLinks; 
     position = MainActivity.positionSelected; 

    } 
    @Override 
    protected Void doInBackground(Void... params) { 
     Document doc = null; 
     String link = "http://votersedge.org"+ positionElements.eq(position).attr("href"); 
     try { 
      doc = Jsoup.connect(link) 
        .userAgent("Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.87 Safari/537.36") 
        .timeout(12000) 
        .followRedirects(true) 
        .get(); 
     } 
     catch(IOException ioe){ 
      ioe.printStackTrace(); 
     } 
     //getting links for reference for further information gathering 
     //need to create initial array to get all links (each has 1 duplicate in the array) 
     // and then create another array to get rid of duplicates 
     Elements links = doc.body().getElementsByClass("CandidateCard_candidate-link_2m1"); 
     String[] cLinks = new String[links.size()]; 
     for(int i=0; i<links.size(); i++) { 
      cLinks[i] = "http://votersedge.org" + links.eq(i).attr("href"); 
     } 
     candidateLinks = new String[links.size()/2]; 
     for(int i=0; i<links.size(); i+=2){ 
      candidateLinks[i/2] = cLinks[i]; 
     } 
     //getting names of candidates 
     Elements names = doc.body().getElementsByClass("CandidateCard_candidate-name_234 col-md-12 col-xs-12 col-sm-12 flush-cols"); 
     namesOfCandidates = new String[names.size()]; 
     for(int i=0; i<names.size(); i++){ 
      namesOfCandidates[i] = names.eq(i).text(); 
     } 
     //getting political parties of candidates 
     Elements attributes = doc.body().getElementsByClass("CandidateCard_candidate-attributes_3qD col-md-12 col-xs-12 col-sm-12 flush-cols"); 
     partiesOfCandidates = new String[names.size()]; 
     for(int i=0; i<names.size(); i++){ 
      partiesOfCandidates[i] = attributes.eq(i).first().child(0).text()+" Candidate"; 
      if(partiesOfCandidates[i].equals(" Candidate")) partiesOfCandidates[i] = "Candidate"; 
     } 
     //getting occupations of candidates 
     occupationsOfCandidates = new String[names.size()]; 
     for(int i=0; i<names.size(); i++){ 
      occupationsOfCandidates[i] = attributes.eq(i).first().child(1).text(); 
     } 

     gotCandidates = true; 
     return null; 
    } 

    @Override 
    protected void onPostExecute(Void result) { 
     super.onPostExecute(result); 
     MainActivity.namesOfCandidates = namesOfCandidates; 
     MainActivity.candidateLinks = candidateLinks; 
     MainActivity.partiesOfCandidates = partiesOfCandidates; 
     MainActivity.occupationsOfCandidates = occupationsOfCandidates; 
     Bundle bundle = new Bundle(); 
     bundle.putStringArray("names", namesOfCandidates); 
     bundle.putStringArray("parties", partiesOfCandidates); 
     bundle.putStringArray("links", candidateLinks); 
     bundle.putStringArray("occupations", occupationsOfCandidates); 


     FragmentManager fm = getSupportFragmentManager(); 
     MainActivity.this.currentFragment = (CardFragment) fm.findFragmentById(R.id.fragmentContainer); 

     if (MainActivity.this.currentFragment == null) { 
      MainActivity.this.currentFragment = new CardFragment(); 
      MainActivity.this.currentFragment.setArguments(bundle); 
      fm.beginTransaction() 
        .add(R.id.fragmentContainer, MainActivity.this.currentFragment) 
        .addToBackStack(null) 
        .commit(); 
     }else{ 
      MainActivity.this.currentFragment = new CardFragment(); 
      MainActivity.this.currentFragment.setArguments(bundle); 
      fm.beginTransaction() 
        .replace(R.id.fragmentContainer, MainActivity.this.currentFragment) 
        .addToBackStack(null) 
        .commit(); 
     } 
     pdLoading.dismiss(); 
    } 

} 

} 

CardFragment.java

public class CardFragment extends Fragment { 

RecyclerView MyRecyclerView; 
String[] namesOfCandidates; 
String[] partiesOfCandidates; 
String[] occupationsOfCandidates; 
String[] candidateLinks; 



@Override 
public void onCreate(@Nullable Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    Log.d("test", "fragment has been created"); 

} 

@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container, 
         Bundle savedInstanceState) { 
    this.getArguments(); 
    namesOfCandidates = this.getArguments().getStringArray("names"); 
    partiesOfCandidates = this.getArguments().getStringArray("parties"); 
    candidateLinks = this.getArguments().getStringArray("links"); 
    occupationsOfCandidates = this.getArguments().getStringArray("occupations"); 
    View view = inflater.inflate(R.layout.fragment_card, container, false); 
    MyRecyclerView = (RecyclerView) view.findViewById(R.id.cardView); 
    MyRecyclerView.setHasFixedSize(true); 
    LinearLayoutManager MyLayoutManager = new LinearLayoutManager(getActivity()); 
    MyLayoutManager.setOrientation(LinearLayoutManager.VERTICAL); 
    if (namesOfCandidates.length > 0 & MyRecyclerView != null) { 
     MyRecyclerView.setAdapter(new MyAdapter(namesOfCandidates)); 
    } 
    MyRecyclerView.setLayoutManager(MyLayoutManager); 

    return view; 
} 

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

} 

public class MyAdapter extends RecyclerView.Adapter<MyViewHolder> { 
    private String[] list; 

    public MyAdapter(String[] Data) { 
     list = Data; 
    } 

    @Override 
    public MyViewHolder onCreateViewHolder(ViewGroup parent,int viewType) { 
     // create a new view 
     View view = LayoutInflater.from(parent.getContext()) 
       .inflate(R.layout.recycle_items, parent, false); 
     return new MyViewHolder(view); 
    } 

    @Override 
    public void onBindViewHolder(final MyViewHolder holder, int position) { 

     holder.titleTextView.setText(list[position]); 
     holder.mainTextView.setText(CardFragment.this.partiesOfCandidates[position]+"Candidate\n"+CardFragment.this.occupationsOfCandidates[position]); 
     holder.arrowImageView.setTag(R.drawable.ic_arrow_forward_black_24dp); 

    } 

    @Override 
    public int getItemCount() { 
     return list.length; 
    } 
} 

public class MyViewHolder extends RecyclerView.ViewHolder { 

    TextView titleTextView; 
    ImageView arrowImageView; 
    TextView mainTextView; 

    public MyViewHolder(View v) { 
     super(v); 
     titleTextView = (TextView) v.findViewById(R.id.titleTextView); 
     mainTextView = (TextView) v.findViewById(R.id.mainTextView); 
     arrowImageView = (ImageView) v.findViewById(R.id.arrowImageView); 
     arrowImageView.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View v) { 


       int id = (int)arrowImageView.getTag(); 
       if(id == R.drawable.ic_arrow_forward_black_24dp) { 

        //MOVE TO NEXT SCREEN 
       } 
      } 
     }); 





    } 
} 

activity_main.xml

<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android" 
xmlns:app="http://schemas.android.com/apk/res-auto" 
android:id="@+id/drawer_layout" 
android:layout_width="match_parent" 
android:layout_height="match_parent"> 
<!-- The main content view --> 
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:id="@+id/fragmentContainer" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    tools:context=".MainActivity"> 
</FrameLayout> 

<!-- Action bar --> 
<android.support.v7.widget.Toolbar 
    android:id="@+id/my_toolbar" 
    android:layout_width="match_parent" 
    android:layout_height="?attr/actionBarSize" 
    android:background="?attr/colorPrimary" 
    android:elevation="4dp" 
    android:theme="@style/ThemeOverlay.AppCompat.ActionBar" 
    app:popupTheme="@style/ThemeOverlay.AppCompat.Light"/> 
<!-- The navigation drawer --> 
<ListView android:id="@+id/left_drawer" 
    android:theme="@style/ThemeOverlay.AppCompat.Light" 
    android:layout_width="240dp" 
    android:layout_height="match_parent" 
    android:layout_gravity="start" 
    android:choiceMode="singleChoice" 
    android:divider="@android:color/transparent" 
    android:dividerHeight="0dp" 
    android:background="#111"/> 
</android.support.v4.widget.DrawerLayout> 

fragment_card.xml

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
xmlns:tools="http://schemas.android.com/tools" 
android:layout_width="match_parent" 
android:layout_height="match_parent" 
android:paddingBottom="@dimen/activity_vertical_margin" 
android:paddingLeft="@dimen/activity_left_margin" 
android:paddingRight="@dimen/activity_right_margin" 
android:paddingTop="@dimen/activity_vertical_margin"> 

<android.support.v7.widget.RecyclerView 
    android:id="@+id/cardView" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" /> 
</RelativeLayout> 

recycle_items.xml

<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android" 
xmlns:card_view="http://schemas.android.com/apk/res-auto" 
android:id="@+id/card_view" 
android:layout_width="match_parent" 
android:layout_height="wrap_content" 
android:layout_margin="5dp" 
card_view:cardCornerRadius="4dp"> 


<LinearLayout 
    android:layout_width="match_parent" 
    android:layout_height="@dimen/card_height" 
    android:orientation="vertical" 
    android:weightSum="4"> 
    <LinearLayout 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:layout_gravity="left|bottom" 
     android:background="@android:drawable/screen_background_dark_transparent" 
     android:orientation="vertical"> 

     <TextView 
      android:id="@+id/titleTextView" 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content" 
      android:padding="16dp" 
      android:textSize="@dimen/text_size" 
      android:textColor="#FFFFFF" 
      android:textStyle="bold" /> 
    </LinearLayout> 

    <LinearLayout 
     android:layout_width="match_parent" 
     android:layout_height="0dip" 
     android:layout_weight="3.2" 
     android:orientation="vertical"> 

     <FrameLayout 
      android:layout_width="match_parent" 
      android:layout_height="match_parent" 
      android:layout_gravity="center_horizontal"> 

      <TextView 
       android:id="@+id/mainTextView" 
       android:layout_width="match_parent" 
       android:layout_height="wrap_content" 
       android:padding="16dp" 
       android:textSize="@dimen/text_size2" 
       android:layout_gravity="center" 
       /> 


     </FrameLayout> 
    </LinearLayout> 

    <LinearLayout 
     android:layout_width="match_parent" 
     android:layout_height="0dip" 
     android:layout_weight="0.8" 
     android:gravity="center|right" 
     android:orientation="horizontal"> 

     <ImageView 
      android:id="@+id/arrowImageView" 
      android:layout_width="@dimen/icon_width" 
      android:layout_height="@dimen/icon_height" 
      android:padding="@dimen/icon_padding" 
      android:src="@drawable/ic_arrow_forward_black_24dp" /> 
    </LinearLayout> 

</LinearLayout> 
</android.support.v7.widget.CardView> 

は、すべてのヘルプははるかに高く評価されます！

Answer 1

私はいくつかのより多くのトラブルシューティングをした、といくつかの工夫の後、私はMyToolbarオブジェクトを取り除くとActionBarDrawerToggleコンテンツが現れた取得ことがわかりました。ご協力ありがとうございました！

Answer 2

論理ANDがではなく、&である必要があります。