tentative d'invoquer la méthode virtuelle « java.util.UUID .. » sur un objet nul refrence lors de l'utilisation Swip Pour Rejeter RecyclerView

Question

J'essaie en utilisant Swip Pour Rejeter RecyclerView, je l'ai utilisé cette tutorial

mais quand J'essaie de supprimer le point dans mon FragmentOne par la méthode swipeToDelete, il montre ce Error:

java.lang.NullPointerException: Attempt to invoke virtual method 'java.util.UUID com.drgnme.listhamrah.Detail.getId()' on a null object reference 
at com.drgnme.listhamrah.DetailLab.deleteDetail(DetailLab.java:82) 
at com.drgnme.listhamrah.FragmentOne$DetailAdapter.swipeToDelete(FragmentOne.java:396) 
at com.drgnme.listhamrah.ItemSwipeHelper.onSwiped(ItemSwipeHelper.java:43) 
at android.support.v7.widget.helper.ItemTouchHelper$4.run(ItemTouchHelper.java:681) 
at android.os.Handler.handleCallback(Handler.java:739) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5451) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 

i utilisé this dans un autre endroit dans ce Fragment pour Delete article et il est un travail très bien, ne savent pas quel est le problème ici ..

this:

DetailLab.get(getActivity()).deleteDetail(mDetail); 
updateUI(); 
updateNumbers(); 

et voici mon FragmentOne:

public class FragmentOne extends Fragment { 
private static final String 
     SAVED_NUMBER_VISIBLE = "number"; 

private RecyclerView mDetailRecyclerView; 
private DetailAdapter mAdapter; 
private boolean mNumberVisible; 

private View view; 

@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setHasOptionsMenu(true); 
} 


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

    mDetailRecyclerView = (RecyclerView) view.findViewById(R.id.detail_recycler_view); 

    LinearLayoutManager layoutManager = new LinearLayoutManager(getContext()); 
    layoutManager.setReverseLayout(true); //This will reverse the data order but not scroll the RecyclerView to the last item 
    layoutManager.setStackFromEnd(true); //For keeping data order same and simply scrolling the RecyclerView to the last item 
    mDetailRecyclerView.setLayoutManager(layoutManager); 

    if (savedInstanceState != null) { 
     mNumberVisible = 
       savedInstanceState.getBoolean(SAVED_NUMBER_VISIBLE); 
    } 

    updateUI(); 


    return view; 
} 

@Override 
public void onResume() { 
    super.onResume(); 
    updateUI(); 
} 

@Override 
public void onSaveInstanceState(Bundle outState) { 
    super.onSaveInstanceState(outState); 
    outState.putBoolean(SAVED_NUMBER_VISIBLE, mNumberVisible); 
} 
.. 
..  


protected void updateUI() { 
    DetailLab detailLab = DetailLab.get(getActivity()); 
    List<Detail> details = detailLab.getDetails(); 
    if (details.size() == 0) { 
     LinearLayout linearLayout = (LinearLayout) view.findViewById(R.id.empty_view); 
     linearLayout.setVisibility(View.VISIBLE); 
    } else { 
     LinearLayout linearLayout = (LinearLayout) view.findViewById(R.id.empty_view); 
     linearLayout.setVisibility(View.GONE); 
    } 

    if (mAdapter == null) { 
     mAdapter = new DetailAdapter(details); 
     mDetailRecyclerView.setAdapter(mAdapter); 

    } else { 
     mAdapter.setDetails(details); 
     mAdapter.notifyDataSetChanged(); 
    } 

    updateNumbers(); 
} 

private class DetailHolder extends RecyclerView.ViewHolder 
     implements View.OnClickListener, View.OnLongClickListener { 
    private TextView mTitleTextView; 
    //  private TextView mDateTextView; 
    private Detail mDetail; 
    private RatingBar mRatingBar; 

    public DetailHolder(LayoutInflater inflater, ViewGroup parent) { 
     super(inflater.inflate(R.layout.list_item_detail, 
       parent, false)); 

     itemView.setOnClickListener(this); 
     itemView.setOnLongClickListener(this); 
     mTitleTextView = (TextView) itemView.findViewById(R.id.detail_title); 
     mRatingBar = (RatingBar) itemView.findViewById(R.id.ratingBar); 
    } 

    public void bind(Detail detail) { 
     mDetail = detail; 
     mTitleTextView.setText(mDetail.getTitle()); 
     mRatingBar.setRating(mDetail.getRate()); 
    } 

    @Override 
    public void onClick(View view) { 
     Intent intent = DetailPagerActivity.newIntent(getActivity(), 
       mDetail.getId()); 
     startActivity(intent); 
    } 

    @Override 
    public boolean onLongClick(View v) { 

     AlertDialog.Builder alert = new AlertDialog.Builder(
       getActivity()); 
     alert.setMessage(R.string.alert); 
     alert.setPositiveButton("Yes", new DialogInterface.OnClickListener() { 
      @Override 
      public void onClick(DialogInterface dialog, int which) { 
       DetailLab.get(getActivity()).deleteDetail(mDetail); 
       updateUI(); 
       updateNumbers(); 
       dialog.dismiss(); 
      } 
     }); 
     alert.setNegativeButton("No", new DialogInterface.OnClickListener() { 
      @Override 
      public void onClick(DialogInterface dialog, int which) { 
       dialog.dismiss(); 
      } 
     }); 
     alert.show(); 
     return true; 
    } 
} 


private class DetailAdapter extends RecyclerView.Adapter<DetailHolder> implements ItemTouchHelperAdapter { 
    private List<Detail> mDetails; 
    private Detail mDetail; 

    public DetailAdapter(List<Detail> details) { 
     mDetails = details; 
    } 

    @Override 
    public DetailHolder onCreateViewHolder(ViewGroup parent, int viewType) { 
     LayoutInflater layoutInflater = 
       LayoutInflater.from(getActivity()); 

     return new DetailHolder(layoutInflater, parent); 
    } 

    @Override 
    public void onBindViewHolder(DetailHolder holder, int position) { 
     Detail detail = mDetails.get(position); 
     holder.bind(detail); 
    } 

    @Override 
    public int getItemCount() { 
     return mDetails.size(); 
    } 

    public void setDetails(final List<Detail> details) { 
     mDetails = details; 


     ItemTouchHelper.Callback itemTouchCallBack=new ItemSwipeHelper(Direction.RIGHT, mAdapter); 
     ItemTouchHelper swipeToDismissTouchHelper =new ItemTouchHelper(itemTouchCallBack); 
     swipeToDismissTouchHelper.attachToRecyclerView(mDetailRecyclerView); 

    } 


    @Override 
    public void swipeToDelete(int position) { 

    DetailLab.get(getActivity()).deleteDetail(mDetail); 
    updateUI(); 
    updateNumbers(); 

    } 
} 
} 

Answer 1

Le problème n'a pas été sur le Library que je l'ai utilisé, je aurais dû donner le item's position pour supprimer, alors je viens d'ajouter cette ligne dans le premier de mes swipeToDelete méthode et résoudre le problème:

mDetail = mDetails.get(position);