RecyclerView selects multiple items on a item click

Question

I have implemented a RecyclerView to display a list of Contacts (200 approximately). A user can select multiple items. The selection make visible a tick to indicate to the user the selected contacts. However, when the user select a item, the tick appears on several non-selected items. The frequency of occurrence is the same.

Could you tell me what I am doing wrong. Thanks !

Here is my implementation :

I have an activity called NewAppointmentActivity which contains a fragment called NewAppointmentPhoneContactsFragment. This fragment is a RecyclerView :

File fragment_new_appointment_phone_contacts.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.recyclerview.widget.RecyclerView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/list"
    android:name="com.example.geoappointment.fragments.NewAppointmentPhoneContactsFragment"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_marginLeft="16dp"
    android:layout_marginRight="16dp"
    app:layoutManager="LinearLayoutManager"
    tools:context=".fragments.NewAppointmentPhoneContactsFragment"
    tools:listitem="@layout/fragment_contact_item" />

File NewAppointmentPhoneContactsFragment.java

public class NewAppointmentPhoneContactsFragment extends Fragment {
    private static final String TAG = "NewAppointmentPhoneCont";

    private NewAppointmentActivityViewModel viewModel;

    public NewAppointmentPhoneContactsFragment() {}

    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        viewModel = new ViewModelProvider(this).get(NewAppointmentActivityViewModel.class);

        new LoadContactsFromPhoneAsyncTask(
                requireActivity().getContentResolver(),
                requireActivity().getApplicationContext(),
                new AsyncTaskCallback<ArrayList<Contact>>() {
                    @Override
                    public void onPostExecuteCallback(ArrayList<Contact> param) {
                        if (viewModel != null) {
                            viewModel.setPhoneContacts(param);
                        }
                    }
                }).execute();
    }

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

        if (view instanceof RecyclerView) {
            Context context = view.getContext();
            RecyclerView recyclerView = (RecyclerView) view;
            recyclerView.setLayoutManager(new LinearLayoutManager(context));
            
            viewModel.getPhoneContacts().observe(getViewLifecycleOwner(), contacts -> {
                recyclerView.setAdapter(new MyContactListRecyclerViewAdapter(contacts));
            });
        }

        return view;
    }
}

When the AsynTask is done, it notifies the model which sets the adapter to the RecyclerView (it works fine).

File MyContactListRecyclerViewAdapter.java

public class MyContactListRecyclerViewAdapter extends RecyclerView.Adapter<MyContactListRecyclerViewAdapter.ViewHolder> {
    private static final String TAG = "MyContactListRecyclerVi";

    private final ArrayList<Contact> mValues;
    private final ArrayList<Contact> mSelectedValues;

    public MyContactListRecyclerViewAdapter(ArrayList<Contact> items) {
        mValues = items;
        mSelectedValues = new ArrayList<>();
    }

    @NotNull
    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater
                .from(parent.getContext())
                .inflate(R.layout.fragment_contact_item, parent, false);
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(final ViewHolder holder, int position) {
        holder.mItem = mValues.get(position);
        holder.mNameTextView.setText(holder.mItem.getName());
        holder.mPhoneNumberView.setText(holder.mItem.getPhoneNumber());

        if (mSelectedValues.contains(holder.mItem)) {
            holder.tickImageView.setVisibility(View.VISIBLE);
        }

        holder.mView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                onItemClick(holder, position);
            }
        });
    }

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

    public void onItemClick(final ViewHolder holder, int position) {
        // Récupération du contact sélectionné
        final Contact contact = mValues.get(position);
        Log.d(TAG, contact.toString());

        // Si le contact n'est pas nul
        if (contact != null) {
            // Si le contact n'est pas déjà sélectionné
            if (!mSelectedValues.contains(contact)) {
                // Ajout du contact dans la liste des contacts sélectionnés
                mSelectedValues.add(contact);

                // Démasque la tick de sélection
                holder.tickImageView.setVisibility(View.VISIBLE);
            } else {
                // Retire le contact de la liste des contacts sélectionnés
                mSelectedValues.remove(contact);

                // Masque la tick de sélection
                holder.tickImageView.setVisibility(View.INVISIBLE);
            }
        }

        Log.d(TAG, mSelectedValues.toString());
    }

    public class ViewHolder extends RecyclerView.ViewHolder {
        public final View mView;
        public final TextView mNameTextView;
        public final TextView mPhoneNumberView;
        public final ImageView tickImageView;
        public Contact mItem;

        public ViewHolder(View view) {
            super(view);
            mView = view;
            mNameTextView = (TextView) view.findViewById(R.id.contactItemNameTextView);
            mPhoneNumberView = (TextView) view.findViewById(R.id.contactItemPhoneNumber);
            tickImageView = (ImageView) view.findViewById(R.id.contactItemTickImageView);

            if (mItem != null) {
                if (mSelectedValues.contains(mItem)) {
                    tickImageView.setVisibility(View.VISIBLE);
                }
            }
        }
    }
}

Answer 1

Add the else branch in the onBindViewHolder to avoid the repetition of the visible ticked items while recycling views

@Override
public void onBindViewHolder(final ViewHolder holder, int position) {
    holder.mItem = mValues.get(position);
    holder.mNameTextView.setText(holder.mItem.getName());
    holder.mPhoneNumberView.setText(holder.mItem.getPhoneNumber());

    if (mSelectedValues.contains(holder.mItem)) {
        holder.tickImageView.setVisibility(View.VISIBLE);
    } else {
        holder.tickImageView.setVisibility(View.GONE);
    }

    holder.mView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            onItemClick(holder, position);
        }
    });
}