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

I wrote a library to handle android recycler view item click event. You can find whole tutorial in https://github.com/ChathuraHettiarachchi/RecycleClick

RecycleClick.addTo(YOUR_RECYCLEVIEW).setOnItemClickListener(new RecycleClick.OnItemClickListener() {
            @Override
            public void onItemClicked(RecyclerView recyclerView, int position, View v) {
                // YOUR CODE
            }
        });

or to handle item long press you can use

RecycleClick.addTo(YOUR_RECYCLEVIEW).setOnItemLongClickListener(new RecycleClick.OnItemLongClickListener() {
            @Override
            public boolean onItemLongClicked(RecyclerView recyclerView, int position, View v) {
                // YOUR CODE
                return true;
            }
        });

Answer 2

recyclerview animation has not been tested, the other is normal. I think it has been optimized to the maximum. Interface has other uses, you can temporarily ignore.

public abstract class BaseAdapterRV<VH extends BaseViewHolder> extends RecyclerView.Adapter<VH> implements AdapterInterface {
    public final String TAG = getClass().getSimpleName();

    protected final Activity mActivity;
    protected final LayoutInflater mInflater;
    protected ItemClickInterface<?, Integer> mListener;

    public BaseAdapterRV(Activity activity) {
        mActivity = activity;
        mInflater = LayoutInflater.from(mActivity);
    }

    @Override
    public final VH onCreateViewHolder(ViewGroup parent, int viewType) {
        return onCreateViewHolder(parent, viewType, mInflater);
    }

    @Override
    public final void onBindViewHolder(VH holder, int position) {
        holder.itemView.setTag(R.id.tag_view_click, position);
        //创建点击事件
        holder.itemView.setOnClickListener(mListener);
        holder.itemView.setOnLongClickListener(mListener);
        onBindVH(holder, position);
    }


    ///////////////////////////////////////////////////////////////////////////
    // 以下是增加的方法
    ///////////////////////////////////////////////////////////////////////////

    /**
     * 注意!涉及到notifyItemInserted刷新时立即获取position可能会不正确
     * 里面也有onItemLongClick
     */
    public void setOnItemClickListener(ItemClickInterface<?, Integer> listener) {
        mListener = listener;
        notifyDataSetChanged();
    }

    @NonNull
    protected abstract VH onCreateViewHolder(ViewGroup parent, int viewType, LayoutInflater inflater);

    protected abstract void onBindVH(VH holder, int position);

}

This is Interface

/**
 * OnItemClickListener的接口
 * 见子类实现{@link OnItemClickListener}{@link OnItemItemClickListener}
 */
public interface ItemClickInterface<DATA1, DATA2> extends View.OnClickListener, View.OnLongClickListener {

    void onItemClick(DATA1 data1, DATA2 data2);

    boolean onItemLongClick(DATA1 data1, DATA2 data2);
}

This is an abstract class

public abstract class OnItemClickListener<DATA> implements ItemClickInterface<View, DATA> {
    @Override
    public void onClick(View v) {
        onItemClick(v, (DATA) v.getTag(R.id.tag_view_click));
    }

    @Override
    public boolean onLongClick(View v) {
        return onItemLongClick(v, (DATA) v.getTag(R.id.tag_view_click));
    }

    @Override
    public boolean onItemLongClick(View view, DATA data) {
        return false;
    }
}

You only need it

    mAdapter.setOnItemClickListener(new OnItemClickListener<Integer>() {
        @Override
        public void onItemClick(View view, Integer integer) {

        }

        @Override
        public boolean onItemLongClick(View view, Integer integer) {
            return true;
        }
    });

Answer 3

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. I hope it'll help you ..!

Answer 4

Guys use this code in Your main activity. Very Efficient Method

RecyclerView recyclerView = (RecyclerView) findViewById(R.id.users_list);            
UsersAdapter adapter = new UsersAdapter(users, this);
recyclerView.setAdapter(adapter);
adapter.setOnCardClickListner(this);

Here is your Adapter class.

public class UsersAdapter extends RecyclerView.Adapter<UsersAdapter.UserViewHolder> {
        private ArrayList<User> mDataSet;
        OnCardClickListner onCardClickListner;


        public UsersAdapter(ArrayList<User> mDataSet) {
            this.mDataSet = mDataSet;
        }

        @Override
        public UserViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.user_row_layout, parent, false);
            UserViewHolder userViewHolder = new UserViewHolder(v);
            return userViewHolder;
        }

        @Override
        public void onBindViewHolder(UserViewHolder holder, final int position) {
            holder.name_entry.setText(mDataSet.get(position).getUser_name());
            holder.cardView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    onCardClickListner.OnCardClicked(v, position);
                }
            });
        }

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

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


        public static class UserViewHolder extends RecyclerView.ViewHolder {
            CardView cardView;
            TextView name_entry;

            public UserViewHolder(View itemView) {
                super(itemView);
                cardView = (CardView) itemView.findViewById(R.id.user_layout);
                name_entry = (TextView) itemView.findViewById(R.id.name_entry);
             }
        }

        public interface OnCardClickListner {
            void OnCardClicked(View view, int position);
        }

        public void setOnCardClickListner(OnCardClickListner onCardClickListner) {
            this.onCardClickListner = onCardClickListner;
        }
    }

After this you will get this override method in your activity.

@Override
    public void OnCardClicked(View view, int position) {
        Log.d("OnClick", "Card Position" + position);
    }

Answer 5

Thanks to @marmor, I updated my answer.

I think it's a good solution to handle the onClick() in the ViewHolder class constructor and pass it to the parent class via OnItemClickListener interface.

MyAdapter.java

public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder>{

private LayoutInflater layoutInflater;
private List<MyObject> items;
private AdapterView.OnItemClickListener onItemClickListener;

public MyAdapter(Context context, AdapterView.OnItemClickListener onItemClickListener, List<MyObject> items) {
    layoutInflater = LayoutInflater.from(context);
    this.items = items;
    this.onItemClickListener = onItemClickListener;
}

@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View view = layoutInflater.inflate(R.layout.my_row_layout, parent, false);
    return new ViewHolder(view);
}

@Override
public void onBindViewHolder(ViewHolder holder, int position) {
    MyObject item = items.get(position);
}

public MyObject getItem(int position) {
    return items.get(position);
}


class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
    private TextView title;
    private ImageView avatar;

    public ViewHolder(View itemView) {
        super(itemView);
        title = itemView.findViewById(R.id.title);
        avatar = itemView.findViewById(R.id.avatar);

        title.setOnClickListener(this);
        avatar.setOnClickListener(this);
        itemView.setOnClickListener(this);
    }

    @Override
    public void onClick(View view) {
        //passing the clicked position to the parent class
        onItemClickListener.onItemClick(null, view, getAdapterPosition(), view.getId());
    }
}
}

Usage of adapter in other classes:

MyFragment.java

public class MyFragment extends Fragment implements AdapterView.OnItemClickListener {

private RecyclerView recycleview;
private MyAdapter adapter;

    .
    .
    .

private void init(Context context) {
    //passing this fragment as OnItemClickListener to the adapter
    adapter = new MyAdapter(context, this, items);
    recycleview.setAdapter(adapter);
}

@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
    //you can get the clicked item from the adapter using its position
    MyObject item = adapter.getItem(position);

    //you can also find out which view was clicked
    switch (view.getId()) {
        case R.id.title:
            //title view was clicked
            break;
        case R.id.avatar:
            //avatar view was clicked
            break;
        default:
            //the whole row was clicked
    }
}

}

Answer 6

Here is a way to implement it quite easily if you have a list of POJOs and want to retrieve one on click from outside the adapter.

In your adapter, create a listener for the click events and a method to set it:

public class MyAdapter extends RecyclerView.Adapter<SitesListAdapter.ViewHolder> {
...
private List<MyPojo> mMyPojos;
private static OnItemClickListener mOnItemClickListener;

...
public interface OnItemClickListener {
    public void onItemClick(MyPojo pojo);
}

...
public void setOnItemClickListener(OnItemClickListener onItemClickListener){
    mOnItemClickListener = onItemClickListener;
}
...

}

In your ViewHolder, implement onClickListener and create a class member to temporarily store the POJO the view is presenting, that way (this is an example, creating a setter would be better):

public static class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
    public MyPojo mCurrentPojo;
    ...
    public ViewHolder(View view) {
        super(v);
        ...
        view.setOnClickListener(this); //You could set this on part of the layout too
    }

    ...
    @Override
    public void onClick(View view) {
        if(mOnItemClickListener != null && mCurrentPojo != null){
            mOnItemClickListener.onItemClick(mCurrentPojo);
        }
    }

Back in your adapter, set the current POJO when the ViewHolder is bound (or to null if the current view doesn't have one):

@Override
public void onBindViewHolder(final ViewHolder holder, final int position) {
    final MyPojo currentPojo = mMyPojos.get(position); 
    holder.mCurrentPojo = currentPojo;
    ...

That's it, now you can use it like this from your fragment/activity:

    mMyAdapter.setOnItemClickListener(new mMyAdapter.OnItemClickListener() {
        @Override
        public void onItemClick(MyPojo pojo) {
            //Do whatever you want with your pojo here
        }
    });