Android Исключение нулевого указателя Использование ListView и фрагментов

Question

Я бегу приложение, и я не могу обернуть мою голову вокруг, почему я получаю сообщение об ошибке, вот трассировки стека

E/AndroidRuntime: FATAL ИСКЛЮЧЕНИЕ: main Процесс: com.kozmiksoftware.swaggster, PID: 10428 java.lang.NullPointerException: попытка вызвать виртуальный метод 'void android.widget.TextView.setText (java.lang.CharSequence)' на нулевой ссылке объекта на com.kozmiksoftware.swaggster.ListView.RecyclerAdapter.onBindViewHolder (RecyclerAdapter.java:62) на android.support.v7.widget.RecyclerView $ Adapter.onBindViewH старше (RecyclerView.java:6279) на android.support.v7.widget.RecyclerView $ Adapter.bindViewHolder (RecyclerView.java:6312) на android.support.v7.widget.RecyclerView $ Recycler.tryBindViewHolderByDeadline (RecyclerView.java: 5258) в android.support.v7.widget.RecyclerView $ Recycler.tryGetViewHolderForPositionByDeadline (RecyclerView.java:5521) в android.support.v7.widget.RecyclerView $ Recycler.getViewForPosition (RecyclerView.java:5363) на андроиде. support.v7.widget.RecyclerView $ Recycler.getViewForPosition (RecyclerView.java:5359) на android.support.v7.widget.LinearLayoutManager $ LayoutState.next (LinearLayoutManager.java:2141) на android.support.v7.widget. LinearLayoutManager.layoutChunk (LinearLayoutManager.java:1525) на android.support.v7.widget.LinearLayoutManager.fill (LinearLayoutManager.java:1488) на android.support.v7.widget.LinearLayoutManager.scrollBy (LinearLayoutManager.java:1305) на android.support.v7.widget. LinearLayoutManager.scrollVerticallyBy (LinearLayoutManager.java:1050) на android.support.v7.widget.RecyclerView $ ViewFlinger.run (RecyclerView.java:4649) на android.view.Choreographer $ CallbackRecord.run (Choreographer.java:871) на android.view.Choreographer.doCallbacks (Хореограф.java:683) на android.view.Choreographer.doFrame (Хореограф.java:616) на android.view.Choreographer $ FrameDisplayEventReceiver.run (Хореограф.java:857) на android.os.Handler.handleCallback (Han dler.java:751) на android.os.Handler.dispatchMessage (Handler.java:95) на android.os.Looper.loop (Looper.java:154) на android.app.ActivityThread.main (ActivityThread. java: 6077) at java.lang.reflect.Method.invoke (собственный метод) at com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run (ZygoteInit.java:865) at com.android.internal.os .ZygoteInit.main (ZygoteInit.java:755)

у меня есть фрагмент, который я пытаюсь добавить заголовок к ListView, я построил пользовательский адаптер и приведен ниже

public class RecyclerAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> { 

private static final int TYPE_HEADER = 0; 
private static final int TYPE_ITEM = 1; 

Header header; 
List<ListItem> listItems; 

public RecyclerAdapter(Header header, List<ListItem> listItems) 
{ 
    this.header = header; 
    this.listItems = listItems; 
} 

@Override 
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { 
    if(viewType == TYPE_HEADER) 
    { 
     View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.header, parent, false); 
     return new VHHeader(v); 
    } 
    else if(viewType == TYPE_ITEM) 
    { 
     View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.model, parent, false); 
     return new VHHeader(v); 
    } 

    throw new RuntimeException("There is no type that matches the type " + viewType + " + make sure your using types correctly"); 

} 

private ListItem getItem(int position) 
{ 
    return listItems.get(position); 
} 


@Override 
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) { 
    if(holder instanceof VHHeader) 
    { 
     VHHeader VHheader = (VHHeader)holder; 
     VHheader.txtFullname.setText(header.getFullname()); 
     VHheader.txtWeb.setText(header.getWeb()); 
     VHheader.txtBio.setText(header.getBio()); 
     VHheader.txtSwaggCount.setText(header.getSwaggCount()); 
     VHheader.txtFollowerCount.setText(header.getFollowerCount()); 
     VHheader.txtFollowingCount.setText(header.getFollowingCount()); 
    } 
    else if(holder instanceof VHItem) 
    { 
     ListItem currentItem = getItem(position - 1); 
     VHItem VHItem = (VHItem)holder; 
     VHItem.txtName.setText(currentItem.getName()); 
     VHItem.iv.setImageResource(currentItem.getId()); 
    } 

} 

// Need to override this method 
public int getItemViewType(int position) { 
    if(isPositionHeader(position)) 
     return TYPE_HEADER; 
    return TYPE_ITEM; 
} 

private boolean isPositionHeader(int position){ 
    return position == 0; 
} 

@Override 
public int getItemCount() { 
    return listItems.size()+1; 
} 

private class VHHeader extends RecyclerView.ViewHolder { 
    TextView txtFullname; 
    TextView txtWeb; 
    TextView txtBio; 
    TextView txtSwaggCount; 
    TextView txtFollowerCount; 
    TextView txtFollowingCount; 
    public VHHeader(View itemView) { 
     super(itemView); 
     this.txtFullname = (TextView)itemView.findViewById(R.id.fullnameTV); 
     this.txtWeb = (TextView)itemView.findViewById(R.id.webTV); 
     this.txtBio= (TextView)itemView.findViewById(R.id.bioTV); 
     this.txtSwaggCount = (TextView)itemView.findViewById(R.id.swaggsCountTV); 
     this.txtFollowerCount = (TextView)itemView.findViewById(R.id.followerCountTV); 
     this.txtFollowingCount = (TextView)itemView.findViewById(R.id.followingCountTV); 
    } 
} 

private class VHItem extends RecyclerView.ViewHolder { 
    TextView txtName; 
    ImageView iv; 
    public VHItem(View itemView){ 
     super(itemView); 
     this.txtName = (TextView)itemView.findViewById(R.id.txtName); 
     this.iv = (ImageView)itemView.findViewById(R.id.ivListItem); 
    } 
} 

}

А вот класс фрагмент

public class Posts extends Fragment { 
private RecyclerView mPostRecyclerView; 

@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container, 
         Bundle savedInstanceState) { 
    // Inflate the layout for this fragment 
    View rootView = inflater.inflate(R.layout.post, container, false); 
    mPostRecyclerView = (RecyclerView) rootView.findViewById(R.id.postListView); 
    mPostRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity())); 

    RecyclerAdapter adapter = new RecyclerAdapter(getHeader(), getListItems()); 
    mPostRecyclerView.setAdapter(adapter); 

    return rootView; 
} 


private Header getHeader() 
{ 
    ParseUser currentUser = ParseUser.getCurrentUser(); 
    String fullname = (String) currentUser.get("fullname"); 
    String bio = (String) currentUser.get("bio"); 
    String web = (String) currentUser.get("web"); 

    Header header = new Header(); 
    header.setFullname(fullname); 
    header.setBio(bio); 
    header.setWeb(web); 
    header.setFollowerCount("1000"); 
    header.setFollowingCount("1000"); 
    header.setSwaggCount("1000"); 

    return header; 

} 

public List<ListItem> getListItems() 
{ 
    List<ListItem> listItems = new ArrayList<ListItem>(); 
    for (int i = 0; i<10; i++) { 
     ListItem item = new ListItem(); 
     item.setName("image" + i); 
     if (i % 2 == 0) 
      item.setId(R.drawable.sweetlife); 
     else 
      item.setId(R.drawable.young); 
     listItems.add(item); 
    } 
    return listItems; 
} 

}

Это говорит об ошибке в onBindViewHolder() метод, я поставил точку останова и проверки адаптера и кажется чтобы я не мог найти нулевой объект, поэтому любая помощь была бы оценена.

Answer 1

Вы должны вернуть VHItem, когда ваш Item is normal item.вы возвращаете VHHeader в обоих типах

@Override 
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int   viewType) { 
if(viewType == TYPE_HEADER) 
{ 
    View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.header, parent, false); 
    return new VHHeader(v); 
} 
else if(viewType == TYPE_ITEM) 
{ 
    View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.model, parent, false); 
    return new VHItem(v); 
} 

throw new RuntimeException("There is no type that matches the type " + viewType + " + make sure your using types correctly"); 

}