Bdtjtk

I want to apply intent to my Fragment from my SeriesVBAdapter, but I get an error. I implemented the interface, but I cannot find the solution. I wanted to send data from SeriesVBAdapter to DescriptionFragment. In doing so, I tried SeriesVBAdapter to DescriptionActivity then DescriptionFragment, but I got the error.

(The solutions on the site mixed my head more.)

SeriesListener

public interface SeriesListener {void seriesKnowledge(String title,String desc,int thumb);}

SeriesRVAdapter

public class SeriesRVAdapter extends RecyclerView.Adapter<SeriesRVAdapter.MyViewHolder> {



private Context mContext;

private List<SeriesDB> mData;

private SeriesListener mSeriesListener;



public SeriesRVAdapter(Context mContext, List<SeriesDB> mData) {

    this.mContext = mContext;

    this.mData = mData;

}



@NonNull

@Override

public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {



    View view;

    LayoutInflater mInflater = LayoutInflater.from(mContext);

    view = mInflater.inflate(R.layout.cardview_item_categories,parent,false);

    MyViewHolder holder = new MyViewHolder(view,mSeriesListener);

    return holder;

}



@Override

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



    holder.seriesTitle.setText(mData.get(position).getTitle());

    holder.seriesImage.setImageResource(mData.get(position).getThumbnail());

    holder.cardView.setOnClickListener(new View.OnClickListener() {

        @Override

        public void onClick(View view) {

            mSeriesListener.seriesKnowledge(mData.get(position).getTitle(),mData.get(position).getDescription(),mData.get(position).getThumbnail());

        }

    });

}



@Override

public int getItemCount() {

    return mData.size();

}



public static class MyViewHolder extends RecyclerView.ViewHolder{



    TextView seriesTitle;

    ImageView seriesImage;

    CardView cardView;

    SeriesListener mSeriesListener;



    public MyViewHolder(View itemView, SeriesListener seriesListener){

        super(itemView);



        seriesTitle = itemView.findViewById(R.id.series_title_id);

        seriesImage = itemView.findViewById(R.id.series_img_id);

        cardView =  itemView.findViewById(R.id.cardview_series_id);

        mSeriesListener = seriesListener;

    }



}

}

DescriptionActivity

public class DescriptionActivity extends AppCompatActivity implements  SeriesListener{



@Override

protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_description);

}





@Override

public void seriesKnowledge(String title, String desc, int thumb) {



    FragmentManager manager = getFragmentManager();



    DecriptionFragment decriptionFragment = (DecriptionFragment) manager.findFragmentById(R.id.description_fr);

    decriptionFragment.sendData(title,desc,thumb);



}

}

DecriptionFragment

public class DecriptionFragment extends Fragment {



View view;

ImageView img;

TextView tx1;

TextView tx2;



@Nullable

@Override

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

    view = inflater.inflate(R.layout.fragment_description,container,false);



    img = view.findViewById(R.id.description_image_id);

    tx1 = view.findViewById(R.id.description_series_id);

    tx2 = view.findViewById(R.id.description_series_category);



    return view;

}



public void sendData(String title, String desc, int thumb)

{

    img.setImageResource(thumb);

    tx1.setText(title);

    tx2.setText(desc);

}

}

CategoriesFragment

public class CategoriesFragment extends Fragment {

View view;

List<SeriesDB> seriesDBS;



@Nullable

@Override

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

    view = inflater.inflate(R.layout.fragment_categories, container, false);



    seriesDBS = new ArrayList<>();

    seriesDBS.add(new SeriesDB("Arrow", "Crime","Decription Arrow",R.drawable.arrow));

    seriesDBS.add(new SeriesDB("Flash", "Crime","Decription Flash",R.drawable.flash));

    seriesDBS.add(new SeriesDB("Supernatural", "Crime","Decription Supernatural",R.drawable.supernatural));

    seriesDBS.add(new SeriesDB("The Originals", "Crime","Decription Originals",R.drawable.originals));

    seriesDBS.add(new SeriesDB("The Legacies", "Crime","Decription Legacies",R.drawable.legacies));

    seriesDBS.add(new SeriesDB("Peaky Blinders", "Crime","Decription Peaky Blinders",R.drawable.peaky));

    seriesDBS.add(new SeriesDB("Arrow", "Crime","Decription Arrow",R.drawable.arrow));

    seriesDBS.add(new SeriesDB("Flash", "Crime","Decription Flash",R.drawable.flash));

    seriesDBS.add(new SeriesDB("Supernatural", "Crime","Decription Supernatural",R.drawable.supernatural));

    seriesDBS.add(new SeriesDB("The Originals", "Crime","Decription Originals",R.drawable.originals));

    seriesDBS.add(new SeriesDB("The Legacies", "Crime","Decription Legacies",R.drawable.legacies));

    seriesDBS.add(new SeriesDB("Peaky Blinders", "Crime","Decription Peaky Blinders",R.drawable.peaky));



    RecyclerView myrv = (RecyclerView) view.findViewById(R.id.recyclerView_series_id);

    SeriesRVAdapter myAdapter = new SeriesRVAdapter(getActivity(),seriesDBS);

    myrv.setLayoutManager(new GridLayoutManager(getContext(),3));

    myrv.setAdapter(myAdapter);

    return view;

}

}

--------- beginning of crash

2018-12-02 17:44:33.663 6704-6704/com.example.forev.neizledim E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.forev.neizledim, PID: 6704
java.lang.NullPointerException: Attempt to invoke interface method 'void com.example.forev.neizledim.SeriesListener.seriesKnowledge(java.lang.String, java.lang.String, int)' on a null object reference
at com.example.forev.neizledim.adapter.recyclerview.SeriesRVAdapter$1.onClick(SeriesRVAdapter.java:49)
at android.view.View.performClick(View.java:5637)
at android.view.View$PerformClick.run(View.java:22429)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)

You are having a nullpointer exception at the onClick method inside you adapter because of mSeriesListener is not initialized so add this to SeriesRVAdapter :

public void setSeriesListener(SeriesListener mSeriesListener) {

    this.mSeriesListener = mSeriesListener;

}

and this to CategoriesFragment :

SeriesRVAdapter myAdapter = new SeriesRVAdapter(getActivity(),seriesDBS);

myAdapter.setSeriesListener(this);

and implement the seriesKnowledge method at the CategoriesFragment:

public void seriesKnowledge(String title,String desc,int thumb){

}

I still haven't figured out the problem yet. I've solved the problem of stopping the application with the comments given by @OussemaAroua , but this time it was not intent. I tried through another solution from another site did intent but didn't pass my data. How can I solve the problem?