Why doesn't RecyclerView have onItemClickListe

Question

I was exploring RecyclerView and I was surprised to see that RecyclerView does not have onItemClickListener(). Because RecyclerView extends

android.view.ViewGroup

and ListView extends

android.widget.AbsListView

. However I solved my problem by writing onClick in my RecyclerView.Adapter:

public static class ViewHolder extends RecyclerView.ViewHolder implements OnClickListener {

    public TextView txtViewTitle;
    public ImageView imgViewIcon;

    public ViewHolder(View itemLayoutView) {
        super(itemLayoutView);
        txtViewTitle = (TextView) itemLayoutView.findViewById(R.id.item_title);
        imgViewIcon = (ImageView) itemLayoutView.findViewById(R.id.item_icon);
    }

    @Override
    public void onClick(View v) {

    }
}

But still I want to know why Google removed onItemClickListener()?

Is there a performance issue or something else?

Answer 1

Check this one in which I have implemented all the things with a proper way

RecyclerViewHolder Class

public class RecyclerViewHolder extends RecyclerView.ViewHolder  {

    //view holder is for girdview as we used in the listView
    public ImageView imageView,imageView2;
    public RecyclerViewHolder(View itemView) {
        super(itemView);
        this.imageView=(ImageView)itemView.findViewById(R.id.image);
    }

}

Adapter

public class RecyclerView_Adapter extends RecyclerView.Adapter<RecyclerViewHolder> {

    //RecyclerView will extend to recayclerview Adapter
    private ArrayList<ModelClass> arrayList;
    private Context context;
    private static RecyclerViewClickListener itemListener;
    //constructor of the RecyclerView Adapter
    RecyclerView_Adapter(Context context,ArrayList<ModelClass> arrayList,RecyclerViewClickListener itemListener){
        this.context=context;
        this.arrayList=arrayList;
        this.itemListener=itemListener;
    }

    @Override
    public RecyclerViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        //this method will inflate the custom layout and return as viewHolder
        LayoutInflater layoutInflater=LayoutInflater.from(parent.getContext());
        ViewGroup mainGroup=(ViewGroup) layoutInflater.inflate(R.layout.single_item,parent,false);
        RecyclerViewHolder listHolder=new RecyclerViewHolder(mainGroup);

        return listHolder;
    }

    @Override
    public void onBindViewHolder(RecyclerViewHolder holder, final int position) {

        final ModelClass modelClass=arrayList.get(position);
        //holder
        RecyclerViewHolder mainHolder=(RecyclerViewHolder)holder;
        //convert the drawable image into bitmap
        Bitmap image= BitmapFactory.decodeResource(context.getResources(),modelClass.getImage());
        //set the image into imageView
        mainHolder.imageView.setImageBitmap(image);
        //to handle on click event when clicked on the recyclerview item and
        // get it through the RecyclerViewHolder class we have defined the views there
        mainHolder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //get the position of the image which is clicked
             itemListener.recyclerViewListClicked(v,position);
            }
        });

    }

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

The interface

public interface RecyclerViewClickListener {

    //this is method to handle the event when clicked on the image in Recyclerview
    public void recyclerViewListClicked(View v,int position);
}

//and to call this method in activity
RecyclerView_Adapter adapter=new RecyclerView_Adapter(Wallpaper.this,arrayList,this);
        recyclerView.setAdapter(adapter);
        adapter.notifyDataSetChanged();


    @Override
    public void  recyclerViewListClicked(View v,int position){

        imageView.setImageResource(wallpaperImages[position]);

    }

Answer 2

I like this way and I'm using it

Inside

public Adapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType)

Put

View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.view_image_and_text, parent, false);
v.setOnClickListener(new MyOnClickListener());

And create this class anywhere you want it

class MyOnClickListener implements View.OnClickListener {
    @Override
    public void onClick(View v) {
       int itemPosition = recyclerView.indexOfChild(v);
       Log.e("Clicked and Position is ",String.valueOf(itemPosition));
    }
}

I've read before that there is a better way but I like this way is easy and not complicated.

Answer 3

See my approach on this:

First declare an interface like this:

/**
 * Interface used for delegating item click events in a {@link android.support.v7.widget.RecyclerView}
 * Created by Alex on 11/28/2015.
 */
  public interface OnRecyclerItemClickListener<T> {

     /**
      * Called when a click occurred inside a recyclerView item view
      * @param view that was clicked
      * @param position of the clicked view
      * @param item the concrete data that is displayed through the clicked view
      */
      void onItemClick(View view, int position, T item);
   }

Then create the adapter:

public class CustomRecyclerAdapter extends RecyclerView.Adapter {      

    private class InternalClickListener implements View.OnClickListener{

      @Override
      public void onClick(View v) {
        if(mRecyclerView != null && mItemClickListener != null){
            // find the position of the item that was clicked
            int position = mRecyclerView.getChildAdapterPosition(v);
            Data data = getItem(position);
            // notify the main listener
            mItemClickListener.onItemClick(v, position, data);
        }
    }
}

private final OnRecyclerItemClickListener mItemClickListener;
private RecyclerView mRecyclerView;    
private InternalClickListener mInternalClickListener;


/**
 *
 * @param itemClickListener used to trigger an item click event
 */
public PlayerListRecyclerAdapter(OnRecyclerItemClickListener itemClickListener){        
    mItemClickListener = itemClickListener;
    mInternalClickListener = new InternalClickListener();
}

@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
   View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.recycler_item, parent, false);

    v.setOnClickListener(mInternalClickListener);

    ViewHolder viewHolder = new ViewHolder(v);
    return viewHolder;
}

@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
    // do your binding here
}

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

@Override
public void onAttachedToRecyclerView(RecyclerView recyclerView) {
    super.onAttachedToRecyclerView(recyclerView);

    mRecyclerView = recyclerView;
}

@Override
public void onDetachedFromRecyclerView(RecyclerView recyclerView) {
    super.onDetachedFromRecyclerView(recyclerView);

    mRecyclerView = null;
}

public Data getItem(int position){
    return mDataset.get(position);
}
}

And now let's see how to integrate this from a fragment:

public class TestFragment extends Fragment implements OnRecyclerItemClickListener<Data>{
   private RecyclerView mRecyclerView;

   @Override
   public void onItemClick(View view, int position, Data item) {
     // do something
   }

   @Override
   public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
      return inflater.inflate(R.layout.test_fragment, container, false);
   }

   @Override
   public void onViewCreated(View view, Bundle savedInstanceState) {
      mRecyclerView = view.findViewById(idOfTheRecycler);
      mRecyclerView .setAdapter(new CustomRecyclerAdapter(this));
   }

Answer 4

Modified my comment...

public class MyViewHolder extends RecyclerView.ViewHolder {

        private Context mContext;

        public MyViewHolder(View itemView) {
            super(itemView);

            mContext = itemView.getContext();

            itemView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {

                    int itemPosition = getLayoutPosition();
                    Toast.makeText(mContext, "" + itemPosition, Toast.LENGTH_SHORT).show();

                }
            });
        }

Answer 5

> How RecyclerView is different from Listview?

One difference is that there is LayoutManager class with RecyclerView by which you can manage your RecyclerView like-

Horizontal or Vertical scrolling by LinearLayoutManager

GridLayout by GridLayoutManager

Staggered GridLayout by StaggeredGridLayoutManager

Like for horizontal scrolling for RecyclerView-

LinearLayoutManager llm = new LinearLayoutManager(context);
llm.setOrientation(LinearLayoutManager.HORIZONTAL);
recyclerView.setLayoutManager(llm);

Answer 6

How to put it all together example...

• onClick() handling
• Cursor - RecyclerView

• ViewHolder types

  public class OrderListCursorAdapter extends CursorRecyclerViewAdapter<OrderListCursorAdapter.ViewHolder> {
  
  private static final String TAG = OrderListCursorAdapter.class.getSimpleName();
  private static final int ID_VIEW_HOLDER_ACTUAL = 0;
  private static final int ID_VIEW_HOLDER = 1;
  
  public OrderListCursorAdapter(Context context, Cursor cursor) {
      super(context, cursor);
  }
  
  public static class ViewHolderActual extends ViewHolder {
      private static final String TAG = ViewHolderActual.class.getSimpleName();
      protected IViewHolderClick listener;
      protected Button button;
  
      public ViewHolderActual(View v, IViewHolderClick listener) {
          super(v, listener);
          this.listener = listener;
          button = (Button) v.findViewById(R.id.orderList_item_button);
          button.setOnClickListener(this);
      }
  
      public void initFromData(OrderData data) {
          Log.d(TAG, "><initFromData(data=" + data + ")");
          orderId = data.getId();
          vAddressStart.setText(data.getAddressStart());
          vAddressEnd.setText(data.getAddressEnd());
      }
  
      @Override
      public void onClick(View view) {
          if (view instanceof Button) {
              listener.onButtonClick((Button) view, getPosition(), this);
          } else {
              super.onClick(view);
          }
      }
  
      public interface IViewHolderClick extends ViewHolder.IViewHolderClick {
          public void onButtonClick(Button button, int position, ViewHolder viewHolder);
      }
  }
  
  public static class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
      private static final String TAG = ViewHolder.class.getSimpleName();
      protected long orderId;
      protected IViewHolderClick listener;
      protected TextView vAddressStart;
      protected TextView vAddressEnd;
      protected TextView vStatus;
  
      public ViewHolder(View v, IViewHolderClick listener) {
          super(v);
          this.listener = listener;
          v.setOnClickListener(this);
  
          vAddressStart = (TextView) v.findViewById(R.id.addressStart);
          vAddressEnd = (TextView) v.findViewById(R.id.addressEnd);
          vStatus = (TextView) v.findViewById(R.id.status);
      }
  
      public void initFromData(OrderData data) {
          Log.d(TAG, "><initFromData(data=" + data + ")");
          orderId = data.getId();
          vAddressStart.setText(data.getAddressStart());
          vAddressEnd.setText(data.getAddressEnd());
      }
  
      public long getOrderId() {
          return orderId;
      }
  
      @Override
      public void onClick(View view) {
          listener.onCardClick(view, getPosition(), this);
      }
  
      public interface IViewHolderClick {
          public void onCardClick(View view, int position, ViewHolder viewHolder);
      }
  }
  
  @Override
  public int getItemViewType(int position) {
      return position == 0 ? ID_VIEW_HOLDER_ACTUAL : ID_VIEW_HOLDER;
  }
  
  @Override
  public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
      Log.d(TAG, ">>onCreateViewHolder(parent=" + parent + ", viewType=" + viewType + ")");
  
      ViewHolder result;
  
      switch (viewType) {
          case ID_VIEW_HOLDER_ACTUAL: {
              View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.card_layout_actual, parent, false);
              result = new ViewHolderActual(itemView, new ViewHolderActual.IViewHolderClick() {
                  @Override
                  public void onCardClick(View view, int position, ViewHolder viewHolder) {
                      Log.d(TAG, "><onCardClick(view=" + view + ", position=" + position + ", viewHolder=" + viewHolder + ")");
                      Intent intent = new Intent(view.getContext(), OrderDetailActivity.class);
                      intent.putExtra(OrderDetailActivity.ARG_ORDER_ID, viewHolder.getOrderId());
                      view.getContext().startActivity(intent);
                  }
  
                  @Override
                  public void onButtonClick(Button button, int position, ViewHolder viewHolder) {
                      Log.d(TAG, "><onButtonClick(button=" + button + ", position=" + position + ", viewHolder=" + viewHolder + ")");
                      Intent intent = new Intent(button.getContext(), OrderMapActivity.class);
                      intent.putExtra(OrderMapActivity.ARG_ORDER_ID, viewHolder.getOrderId());
                      button.getContext().startActivity(intent);
                  }
              });
              break;
          }
          case ID_VIEW_HOLDER:
          default: {
              View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.card_layout, parent, false);
              result = new ViewHolder(itemView, new ViewHolder.IViewHolderClick() {
                  @Override
                  public void onCardClick(View view, int position, ViewHolder viewHolder) {
                      Log.d(TAG, "><onCardClick(view=" + view + ", position=" + position + ", viewHolder=" + viewHolder + ")");
                      Intent intent = new Intent(view.getContext(), OrderDetailActivity.class);
                      intent.putExtra(OrderDetailActivity.ARG_ORDER_ID, viewHolder.getOrderId());
                      view.getContext().startActivity(intent);
                  }
              });
              break;
          }
      }
  
      Log.d(TAG, "<<onCreateViewHolder(parent=" + parent + ", viewType=" + viewType + ")= " + result);
      return result;
  }
  
  @Override
  public void onBindViewHolder(ViewHolder viewHolder, Cursor cursor) {
      Log.d(TAG, "><onBindViewHolder(viewHolder=" + viewHolder + ", cursor=" + cursor + ")");
      final OrderData orderData = new OrderData(cursor);
      viewHolder.initFromData(orderData);
  }
  }