BaseAdapter возвращает нуль

Question

У меня есть фрагмент с видом foldingcell

вот mainfragment -

public class FriendFragmentMain extends Fragment { 

private static final String TAG = FriendFragmentMain.class.getSimpleName(); 
private FriendsCellListAdapter friendsCellListAdapter; 
private List<FriendsItem> friendsItems; 
private String URL_FRIEND="http://212.224.76.127/friends/friends.json"; 
private FragmentActivity fragmentActivity; 
private Activity mActivity; 
private ListView friendsListView; 

public static FriendFragmentMain newInstance(){ 
    FriendFragmentMain friendFragmentMain = new FriendFragmentMain(); 
    return friendFragmentMain; 
} 

@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { 
    View view = inflater.inflate(R.layout.friend_fragment_main, container, false); 

    friendsListView = (ListView) getActivity().findViewById(R.id.friend_super_list); 

    friendsItems = new ArrayList<>(); 
    friendsCellListAdapter = new FriendsCellListAdapter(mActivity, friendsItems); 
    friendsListView.setAdapter(friendsCellListAdapter); 

    friendsListView.setOnItemClickListener(new AdapterView.OnItemClickListener() { 
     @Override 
     public void onItemClick(AdapterView<?> adapterView, View view, int pos, long l) { 
      ((FoldingCell) view).toggle(false); 
      friendsCellListAdapter.registerToggle(pos); 
     } 
    }); 

    Cache cache = AppController.getInstance().getRequestQueue().getCache(); 
    Cache.Entry entry = cache.get(URL_FRIEND); 
    if (entry != null){ 
     try { 
      String data = new String(entry.data, "UTF-8"); 
      try { 
       parseJsonFriend(new JSONObject(data)); 
      } catch (JSONException e){ 
       e.printStackTrace(); 
      } 
     }catch (UnsupportedEncodingException e){ 
      e.printStackTrace(); 
     } 
    } else { 
     JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.GET, 
       URL_FRIEND, null, new Response.Listener<JSONObject>() { 
      @Override 
      public void onResponse(JSONObject response) { 
       VolleyLog.d(TAG, "Response:" + response.toString()); 
       if (response != null) { 
        parseJsonFriend(response); 
       } 
      } 
     }, new Response.ErrorListener() { 
      @Override 
      public void onErrorResponse(VolleyError error) { 
       VolleyLog.d(TAG, "ERROR:" + error.getMessage()); 
      } 
     }); 
     AppController.getInstance().addToRequestQueue(jsonObjectRequest); 
    } 

    return view; 
} 

private void parseJsonFriend(JSONObject response){ 
    try { 
     JSONArray friendArray = response.getJSONArray("friends"); 
     for (int i =0; i < friendArray.length(); i++){ 
      JSONObject friendObj = (JSONObject) friendArray.get(i); 

      FriendsItem item = new FriendsItem(); 
      item.setId(friendObj.getInt("id")); 
      item.setName(friendObj.getString("name")); 
      item.setProfilePic(friendObj.getString("profilePic")); 
      item.setBackgroundImage(friendObj.getString("backgroundImage")); 
      item.setStatus(friendObj.getString("status")); 
      item.setWork(friendObj.getString("work")); 
      item.setLocation(friendObj.getString("location")); 

      String friendUrl = friendObj.isNull("website")? null : friendObj 
        .getString("website"); 
      item.setWebsite(friendUrl); 

      friendsItems.add(item); 
     } 
     friendsCellListAdapter.notifyDataSetChanged(); 
    } catch (JSONException e){ 
     e.printStackTrace(); 
    } 
} 

@Override 
public void onAttach(Activity activity) { 
    super.onAttach(activity); 
    mActivity = activity; 
} 
} 

базовый адаптер выглядит так -

public class FriendsCellListAdapter extends BaseAdapter{ 
private HashSet<Integer> unfoldedIndexes = new HashSet<>(); 
private View.OnClickListener defaultMessageButton; 
private View.OnClickListener defaultViewProfileButton; 
private Activity activity; 
private Context context; 
private LayoutInflater inflater; 

private List<FriendsItem> friendsItems; 
ImageLoader imageLoader = AppController.getInstance().getImageLoader(); 


public FriendsCellListAdapter(Activity activity, List<FriendsItem> friendsItems){ 
    this.activity = activity; 
    this.friendsItems = friendsItems; 
} 

@Override 
public int getCount() { 
    return friendsItems.size(); 
} 

@Override 
public long getItemId(int position) { 
    return position; 
} 

@Override 
public Object getItem(int position) { 
    return friendsItems.get(position); 
} 

@Override 
public View getView(int position, View convertView, ViewGroup parent) { 
    if (imageLoader == null) 
     imageLoader = AppController.getInstance().getImageLoader(); 
    if (inflater==null) 
     inflater = (LayoutInflater)activity 
       .getSystemService(Context.LAYOUT_INFLATER_SERVICE); 

    FriendsItem item = friendsItems.get(position); 

    FoldingCell cell = (FoldingCell) convertView; 
    ViewHolder viewHoler; 

    if (cell == null){ 
     viewHoler = new ViewHolder(); 
     cell = (FoldingCell) inflater.inflate(R.layout.friends_cell, parent, false); 

     viewHoler.profilePic = (NetworkImageView) cell.findViewById(R.id.friends_profile_pic); 
     viewHoler.clientName = (LoginTextView) cell.findViewById(R.id.client_name); 
     viewHoler.friendStatus = (LoginTextView) cell.findViewById(R.id.friend_status); 
     viewHoler.backgroundImage = (NetworkImageView) cell.findViewById(R.id.friend_background_image); 
     viewHoler.friendAvatar = (NetworkImageView) cell.findViewById(R.id.friends_avatar); 
     viewHoler.friendName = (LoginTextView) cell.findViewById(R.id.friend_name); 
     viewHoler.friendLocation = (LoginTextView) cell.findViewById(R.id.friend_location); 
     viewHoler.friendURL = (LoginTextView) cell.findViewById(R.id.friend_url); 
     viewHoler.friendWork = (LoginTextView) cell.findViewById(R.id.friend_work); 
     cell.setTag(viewHoler); 
    } else { 
     if (unfoldedIndexes.contains(position)){ 
      cell.unfold(true); 
     } else { 
      cell.fold(true); 
     } 
     viewHoler = (ViewHolder) cell.getTag(); 
    } 

    viewHoler.clientName.setText(item.getName()); 
    viewHoler.friendName.setText(item.getName()); 

    //chech for empty status 
    if (!TextUtils.isEmpty(item.getStatus())){ 
     viewHoler.friendStatus.setText(item.getStatus()); 
     viewHoler.friendStatus.setVisibility(View.VISIBLE); 
    } else { 
     viewHoler.friendStatus.setVisibility(View.GONE); 
    } 

    //check for empty location 
    if (!TextUtils.isEmpty(item.getLocation())){ 
     viewHoler.friendLocation.setText(item.getLocation()); 
     viewHoler.friendLocation.setVisibility(View.VISIBLE); 
    } else { 
     viewHoler.friendLocation.setVisibility(View.GONE); 
    } 

    //check for null url 
    if (item.getWebsite() != null){ 
     viewHoler.friendURL.setText(Html.fromHtml("<a href=\""+item.getWebsite()+"\">" + item.getWebsite()+"</a>")); 
     viewHoler.friendURL.setMovementMethod(LinkMovementMethod.getInstance()); 
     viewHoler.friendURL.setVisibility(View.VISIBLE); 
    } else { 
     viewHoler.friendURL.setVisibility(View.GONE); 
    } 

    //check for empty work 
    if (!TextUtils.isEmpty(item.getWork())){ 
     viewHoler.friendWork.setText(item.getWork()); 
     viewHoler.friendWork.setVisibility(View.VISIBLE); 
    }else { 
     viewHoler.friendWork.setVisibility(View.GONE); 
    } 

    //profile pic 
    viewHoler.profilePic.setImageUrl(item.getProfilePic(), imageLoader); 
    viewHoler.friendAvatar.setImageUrl(item.getProfilePic(), imageLoader); 

    //background image 
    viewHoler.backgroundImage.setImageUrl(item.getBackgroundImage(), imageLoader); 

    return convertView; 
} 

public void registerToggle(int position){ 
    if (unfoldedIndexes.contains(position)) 
     registerFold(position); 
    else 
     registerUnfold(position); 
} 

public void registerFold(int position){unfoldedIndexes.remove(position);} 

public void registerUnfold(int position){ 
    unfoldedIndexes.add(position); 
} 

private class ViewHolder{ 
    NetworkImageView profilePic; 
    LoginTextView clientName; 
    LoginTextView friendStatus; 
    NetworkImageView backgroundImage; 
    NetworkImageView friendAvatar; 
    LoginTextView friendName; 
    LoginTextView friendLocation; 
    LoginTextView friendURL; 
    LoginTextView friendWork; 
} 
} 

теперь, когда я его запускаю его броски -

Attempt to invoke virtual method 'void android.widget.ListView.setAdapter(android.widget.ListAdapter)' on a null object reference 
          at com.evolustudios.askin.askin.src.fragments.FriendFragmentMain.onCreateView(FriendFragmentMain.java:60) 

эта ошибка. Я не могу узнать, почему он выбрасывает нулевой объект? может ли кто-нибудь рассказать о том, почему он показывает нулевой объект.

взгляды здесь- friends_cell

<com.ramotion.foldingcell.FoldingCell xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="match_parent" android:layout_height="wrap_content" 
    xmlns:folding-cell="http://schemas.android.com/apk/res-auto" 
    folding-cell:additionalFlipsCount="2" 
    folding-cell:animationDuration="1300" 
    folding-cell:backSideColor="@color/bgBackSideColor"> 

    <include layout="@layout/friends_content_layout"/> 

    <include layout="@layout/friends_cell_title_layout"/> 

</com.ramotion.foldingcell.FoldingCell> 

friends_cell_title_layout -

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
android:orientation="horizontal" android:layout_width="match_parent" 
android:layout_height="wrap_content" 
android:baselineAligned="false"> 

<!--LEFT Part --> 
<RelativeLayout 
    android:layout_width="match_parent" 
    android:layout_height="155dp" 
    android:layout_weight="3" 
    android:gravity="center_horizontal" 
    android:orientation="vertical" 
    android:paddingBottom="20dp" 
    android:paddingLeft="10dp" 
    android:paddingRight="10dp" 
    android:paddingTop="20dp" 
    android:background="@color/feed_item_border"> 
    <com.android.volley.toolbox.NetworkImageView 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     android:id="@+id/friends_profile_pic" 
     android:scaleType="fitCenter"/> 
</RelativeLayout> 

<!--RIGHT Part--> 
<RelativeLayout 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:layout_weight="1" 
    android:paddingBottom="20dp" 
    android:paddingEnd="20dp" 
    android:paddingStart="15dp" 
    android:paddingTop="20dp" 
    android:background="@color/feed_item_border"> 
    <ImageView 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_alignParentStart="true" 
     android:id="@+id/title_from_to_dots" 
     android:layout_marginEnd="10dp" 
     android:src="@drawable/from_to_purple"/> 
    <com.evolustudios.askin.askin.src.customfonts.LoginTextView 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:id="@+id/client_name" 
     android:layout_alignTop="@+id/title_from_to_dots" 
     android:layout_marginTop="-5dp" 
     android:layout_toEndOf="@+id/title_from_to_dots" 
     android:ellipsize="marquee" 
     android:fadingEdge="horizontal" 
     android:singleLine="true" 
     android:textColor="@android:color/holo_blue_dark" 
     android:textSize="16sp"/> 
    <ImageView 
     android:layout_width="match_parent" 
     android:layout_height="1dp" 
     android:id="@+id/friend_profile_divider" 
     android:layout_below="@+id/client_name" 
     android:layout_marginBottom="5dp" 
     android:layout_marginTop="5dp" 
     android:layout_toEndOf="@+id/title_from_to_dots" 
     android:src="@color/contentDividerLine"/> 
    <com.evolustudios.askin.askin.src.customfonts.LoginTextView 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:id="@+id/friend_status" 
     android:layout_below="@+id/friend_profile_divider" 
     android:layout_toEndOf="@+id/title_from_to_dots" 
     android:ellipsize="marquee" 
     android:fadingEdge="horizontal" 
     android:singleLine="true" 
     android:textColor="@android:color/holo_blue_dark" 
     android:textSize="16sp"/> 
</RelativeLayout> 

и friend_content_layout -

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:orientation="vertical" android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:visibility="gone"> 

    <!--Content header line--> 
    <RelativeLayout 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     android:background="@color/text_password" 
     android:paddingBottom="7dp" 
     android:paddingLeft="12dp" 
     android:paddingRight="12dp" 
     android:paddingTop="7dp"> 

     <ImageView 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:layout_alignParentStart="true" 
      android:layout_centerVertical="true" 
      android:src="@drawable/menu_icon"/> 
    </RelativeLayout> 

    <!--Content header Image--> 
    <RelativeLayout 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content"> 

     <com.android.volley.toolbox.NetworkImageView 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content" 
      android:id="@+id/friend_background_image" 
      android:scaleType="centerCrop"/> 
    </RelativeLayout> 

    <!--Content body layout--> 
    <LinearLayout 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:orientation="vertical" 
     android:paddingBottom="6dp" 
     android:paddingLeft="20dp" 
     android:paddingRight="20dp" 
     android:paddingTop="9dp"> 

     <!--avatar and name--> 
     <RelativeLayout 
      android:layout_width="wrap_content" 
      android:layout_height="match_parent"> 

      <com.android.volley.toolbox.NetworkImageView 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:id="@+id/friends_avatar" 
       android:layout_alignParentStart="true" 
       android:layout_marginBottom="5dp"/> 

      <com.evolustudios.askin.askin.src.customfonts.LoginTextView 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:id="@+id/friend_name" 
       android:layout_alignTop="@+id/friends_avatar" 
       android:layout_marginBottom="2dp" 
       android:layout_marginStart="10dp" 
       android:layout_toEndOf="@+id/friends_avatar" 
       android:textColor="@color/mainTextColor" 
       android:textSize="18sp" 
       android:textStyle="bold"/> 

      <com.evolustudios.askin.askin.src.customfonts.LoginTextView 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:id="@+id/friend_location" 
       android:layout_alignStart="@+id/friend_name" 
       android:layout_marginBottom="-2dp" 
       android:layout_marginStart="3dp" 
       android:layout_below="@+id/friend_name" 
       android:textColor="#a9a9a9" 
       android:textSize="12sp"/> 
     </RelativeLayout> 

     <!--Divider Line--> 
     <ImageView 
      android:layout_width="match_parent" 
      android:layout_height="1dp" 
      android:layout_marginBottom="6dp" 
      android:layout_marginTop="9dp" 
      android:src="@color/contentDividerLine"/> 

     <!--Address Part--> 
     <LinearLayout 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content" 
      android:baselineAligned="false" 
      android:orientation="horizontal"> 

      <RelativeLayout 
       android:layout_width="0dp" 
       android:layout_height="wrap_content" 
       android:layout_weight="1"> 

       <com.evolustudios.askin.askin.src.customfonts.LoginTextView 
        android:layout_width="wrap_content" 
        android:layout_height="wrap_content" 
        android:id="@+id/url_badge" 
        android:textColor="#a9a9a9" 
        android:layout_alignParentStart="true" 
        android:text="WEBSITE"/> 
       <com.evolustudios.askin.askin.src.customfonts.LoginTextView 
        android:layout_width="wrap_content" 
        android:layout_height="wrap_content" 
        android:id="@+id/friend_url" 
        android:layout_alignStart="@+id/url_badge" 
        android:layout_below="@+id/url_badge" 
        android:textColor="@color/mainTextColor" 
        android:textSize="18sp" 
        android:textStyle="bold"/> 
      </RelativeLayout> 
     </LinearLayout> 

     <!--Divider Line--> 
     <ImageView 
      android:layout_width="match_parent" 
      android:layout_height="1dp" 
      android:layout_marginBottom="6dp" 
      android:layout_marginTop="7dp" 
      android:src="@color/contentDividerLine"/> 

     <!--Work Part--> 
     <LinearLayout 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content" 
      android:baselineAligned="false" 
      android:orientation="horizontal"> 

      <RelativeLayout 
       android:layout_width="0dp" 
       android:layout_height="wrap_content" 
       android:layout_weight="1"> 

       <com.evolustudios.askin.askin.src.customfonts.LoginTextView 
        android:layout_width="wrap_content" 
        android:layout_height="wrap_content" 
        android:id="@+id/work_badge" 
        android:textColor="#a9a9a9" 
        android:layout_alignParentStart="true" 
        android:text="WORK"/> 
       <com.evolustudios.askin.askin.src.customfonts.LoginTextView 
        android:layout_width="wrap_content" 
        android:layout_height="wrap_content" 
        android:id="@+id/friend_work" 
        android:layout_alignStart="@+id/work_badge" 
        android:layout_below="@+id/work_badge" 
        android:textColor="@color/mainTextColor" 
        android:textSize="18sp" 
        android:textStyle="bold"/> 
      </RelativeLayout> 
     </LinearLayout> 

     <!--Buttons--> 
     <com.evolustudios.askin.askin.src.customfonts.LoginTextView 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content" 
      android:id="@+id/friend_send_message" 
      android:layout_marginTop="16dp" 
      android:background="@color/btnRequest" 
      android:padding="10dp" 
      android:text="Send Message" 
      android:textAlignment="center" 
      android:textColor="@color/mainTextColor" 
      android:textSize="20sp"/> 
     <com.evolustudios.askin.askin.src.customfonts.LoginTextView 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content" 
      android:id="@+id/friend_view_profile" 
      android:layout_marginTop="16dp" 
      android:background="@color/btnRequest" 
      android:padding="10dp" 
      android:text="View Profile" 
      android:textAlignment="center" 
      android:textColor="@color/mainTextColor" 
      android:textSize="20sp"/> 
    </LinearLayout> 
</LinearLayout> 

Answer 1

Initialize friendsItems, прежде чем передавать его до friendsCellListAdapter

friendsItems = new ArrayList<FriendsItem>(); // add this line 
friendsCellListAdapter = new FriendsCellListAdapter(mActivity, friendsItems); 
friendsListView.setAdapter(friendsCellListAdapter);