Why is recyclerview not showing in fragment but working in Activity?

Question

Java

recyclerview is not showing in fragment, just empty fragment. Although everything works in a normal activity, the data is loaded from the database in the log, it is displayed that the data has been added, but is not displayed in the fragment ..

spoiler

public class Income extends Fragment implements View.OnClickListener {
 MyDatabaseHelper myDB;
    TextView no_data;
    ImageView empty_imageview;
    Float translationY = 100f;
    Boolean isMenuOpen = false;
    OvershootInterpolator interpolator = new OvershootInterpolator();
    private RecyclerView mRecyclerView;
    CustomAdapter customAdapter;
    ArrayList<String> id_txt,textName,textIncome,textExpenses,textTotal, textDate;
    FloatingActionButton fab_menu, fab_reset, fab_scan, fab_add;
    Activity activity;
    Context context;



    public Income() {


    }


    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view = LayoutInflater.from(container.getContext()).inflate(R.layout.income_fragment, container, false);
        mRecyclerView = (RecyclerView) view.findViewById(R.id.income_recyclerview);
        mRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
        mRecyclerView.setItemAnimator(new DefaultItemAnimator());
        mRecyclerView.setAdapter(new CustomAdapter(getActivity(),getContext(),id_txt, textName, textIncome,
               textExpenses,textTotal,textDate));

        fab_menu = view.findViewById(R.id.fab_menu);
        fab_scan = view.findViewById(R.id.fab_scan);
        fab_reset = view.findViewById(R.id.fab_reset);
        fab_add = view.findViewById(R.id.fab_add);

        loadData();

        initFabMenu();

        return view;


    }
        @Override
        public void onClick(View view) {
            switch (view.getId()) {
                case R.id.fab_menu:
                    if (isMenuOpen) {
                        closeMenu();
                    } else {
                        openMenu();
                    }
                    break;
                case R.id.fab_scan:
                    startActivity(new Intent(getActivity(), ScanActivity.class));
                    break;
                case R.id.fab_add:
                    startActivity(new Intent(getActivity(),AddActivity.class));
                    break;
            }
    }

    private void initFabMenu(){

        fab_scan.setAlpha(0f);
        fab_reset.setAlpha(0f);
        fab_add.setAlpha(0f);

        fab_menu.setOnClickListener(this);
        fab_scan.setOnClickListener(this);
        fab_reset.setOnClickListener(this);
        fab_add.setOnClickListener(this);

        fab_scan.setTranslationY(translationY);
        fab_reset.setTranslationY(translationY);
        fab_add.setTranslationY(translationY);

    }

    private void openMenu(){
        isMenuOpen = !isMenuOpen;

        fab_menu.animate().setInterpolator(interpolator).rotationBy(45f).setDuration(300).start();

        fab_scan.animate().translationY(0f).alpha(1f).setInterpolator(interpolator).setDuration(300).start();
        fab_reset.animate().translationY(0f).alpha(1f).setInterpolator(interpolator).setDuration(300).start();
        fab_add.animate().translationY(0f).alpha(1f).setInterpolator(interpolator).setDuration(300).start();
    }

    private void closeMenu(){
        isMenuOpen = !isMenuOpen;

        fab_menu.animate().setInterpolator(interpolator).rotationBy(0f).setDuration(300).start();


        fab_scan.animate().translationY(translationY).alpha(0f).setInterpolator(interpolator).setDuration(300).start();
        fab_reset.animate().translationY(translationY).alpha(0f).setInterpolator(interpolator).setDuration(300).start();
        fab_add.animate().translationY(translationY).alpha(0f).setInterpolator(interpolator).setDuration(300).start();


    }

    private void initNoDataView(){
      empty_imageview = view.findViewById(R.id.empty_imageview);
      no_data = view.findViewById(R.id.no_data);
    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if(requestCode == 1){
            recreate();
        }
    }

    private void recreate() {
    }

    private void storeDataInArrays() {
       Cursor cursor = myDB.readAllData();
       if (cursor.getCount() == 0) {
            empty_imageview.setVisibility(View.VISIBLE);
            no_data.setVisibility(View.VISIBLE);
       } else {
           while (cursor.moveToNext()) {
               id_txt.add(cursor.getString(0));
               textName.add(cursor.getString(1));
               textIncome.add(cursor.getString(2));
               textDate.add(cursor.getString(3));
           }
           empty_imageview.setVisibility(View.GONE);
           no_data.setVisibility(View.GONE);
       }
   }

   private void loadData(){
       myDB = new MyDatabaseHelper(getContext());
       //myDB = new MyDatabaseHelper(MainActivity.this);

       id_txt = new ArrayList<>();
       textName = new ArrayList<>();
       textIncome = new ArrayList<>();
       textExpenses = new ArrayList<>();
       textTotal = new ArrayList<>();
       textDate = new ArrayList<>();
   }
}


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

    private Context context;
    private Activity activity;
    private ArrayList id_txt, textName, textIncome, textExpenses,textTotal, textDate;




    public CustomAdapter(Activity activity, Context context,ArrayList<String> id_txt, ArrayList<String> textName,
                         ArrayList<String> textIncome, ArrayList<String> textExpenses,
                         ArrayList<String> textTotal, ArrayList<String> textDate) {
        this.activity = activity;
        this.context = context;
        this.id_txt = id_txt;
        this.textName = textName;
        this.textIncome = textIncome;
        this.textExpenses = textExpenses;
        this.textTotal = textTotal;
        this.textDate = textDate;
    }

    @NonNull
    @Override
    public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        LayoutInflater inflater = LayoutInflater.from(context);
        View view = inflater.inflate(R.layout.my_row, parent, false);
        return new MyViewHolder(view);
    }

    @RequiresApi(api = Build.VERSION_CODES.M)
    @Override
    public void onBindViewHolder(@NonNull final MyViewHolder holder, final int position) {
        holder.id_txt.setText(String.valueOf(id_txt.get(position)));
        holder.textName.setText(String.valueOf(textName.get(position)));
        holder.textIncome.setText(String.valueOf(textIncome.get(position)));
        holder.textExpenses.setText(String.valueOf(textExpenses.get(position)));
        holder.textTotal.setText(String.valueOf(textTotal.get(position)));
        holder.textDate.setText(String.valueOf(textDate.get(position)));
        //Recyclerview onClickListener
        holder.mainLayout.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(context, UpdateActivity.class);
                intent.putExtra("id", String.valueOf(id_txt.get(position)));
                intent.putExtra("name", String.valueOf(textName.get(position)));
                intent.putExtra("income", String.valueOf(textIncome.get(position)));
                intent.putExtra("expenses", String.valueOf(textExpenses.get(position)));
                intent.putExtra("total", String.valueOf(textTotal.get(position)));
                intent.putExtra("date", String.valueOf(textDate.get(position)));
                activity.startActivityForResult(intent, 1);
            }
        });


    }

    @Override
    public int getItemCount() {
//        return id_txt.size();
        return (id_txt == null) ? 0: id_txt.size();
    }

    class MyViewHolder extends RecyclerView.ViewHolder {

        TextView id_txt, textName, textIncome, textExpenses,textTotal,textDate;
        LinearLayout mainLayout;

        MyViewHolder(@NonNull View itemView) {
            super(itemView);
            id_txt = itemView.findViewById(R.id.id_txt);
            textName = itemView.findViewById(R.id.textName);
            textIncome = itemView.findViewById(R.id.textIncome);
            textExpenses = itemView.findViewById(R.id.textExpenses);
            textTotal = itemView.findViewById(R.id.textTotal);
            mainLayout = itemView.findViewById(R.id.mainLayout);
            textDate = itemView.findViewById(R.id.textDate);
            //Animate Recyclerview
            Animation translate_anim = AnimationUtils.loadAnimation(context, R.anim.translate_anim);
            mainLayout.setAnimation(translate_anim);
        }

    }

}

Answer 1

Run the debugger and see what the database returns and why the data in the adapter is not loaded.

Answer 2

storeDataInArrays is not called anywhere.
loadData doesn't actually do anything.
notify* methods on the adapter are not called.
In general, the point is not in the fragment, but in the fact that the code is not completed.