在RecyclerView上获取对ViewHolder的引用请点击

Question

This is my first attempt at implementing the RecyclerView . I have implemented a Callback interface between the Adapter and the ViewHolder Class to handle Click Events on the UI elements (buttons). I am having problems getting a reference to the ViewHolder that the click occurred in. I can click the Button for the first item in the list, however the action that i'd defined is performed on the last viewholder in my recycler view. I finally figured out to pass the position through my interface, but I'm struggling to understand how to get a reference to that viewholder` from it.

    public class RoomAdapter extends RecyclerView.Adapter<RoomAdapter.RoomViewHolder>
{
    List<Room> mRooms;
    public RoomAdapter(List<Room> rooms) {
        mRooms = rooms;
    }

    @Override
    public RoomViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
        final View viewItem = LayoutInflater
                .from(viewGroup.getContext())
                .inflate(R.layout.room_rv_item,viewGroup,false);
        return vh = new RoomViewHolder(viewItem,new IRoomViewClick() {
            @Override
            public void editname(int pos) {

            }
        });
    }

    @Override
    public void onBindViewHolder(RoomViewHolder roomViewHolder, int i) {
        Room r = getItem(i);
        roomViewHolder.label.setText(r.name);


    }
    public Room getItem(int position)
    {
        return mRooms.get(position);
    }
    @Override
    public long getItemId(int position) {
        return mRooms.get(position).getId();
    }

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

    public static class RoomViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener
    {
        TextView label;
        Button editBtn;
        LinearLayout labelView;
        Button saveBtn;
        Button deleteBtn;
        EditText editNameET;
        IRoomViewClick mListener;
        public RoomViewHolder(View itemView, IRoomViewClick listener) {
            super(itemView);
            labelView = (LinearLayout) itemView.findViewById(R.id.labelview);
            mListener = listener;
            editBtn =(Button) itemView.findViewById(R.id.editbtn);
            editBtn.setOnClickListener(this);
            label = (TextView) itemView.findViewById(R.id.room_listitem_label);

        }

        @Override
        public void onClick(View view) {
            int pos = getPosition();
            mListener.editname(pos);



        }
    }
    public static interface IRoomViewClick
    {
        public void editname(int pos);
    }

}

Answer 1

you can set a tag for the editBtn in onBindViewHolder :

    public RoomViewHolder(View itemView, IRoomViewClick listener) {
        ....
        editBtn =(Button) itemView.findViewById(R.id.editbtn);
        //add tag for this view
        editBtn.setTag(this);
        ....
   }

and get it in onClick

    @Override
    public void onClick(View view) {
        //getTag
        RoomViewHolder holder = (RoomViewHolder )(view.getTag());
        int pos = getPosition();
        mListener.editname(pos);
    ...
    }

Answer 2

Actually you can do better than getTag by calling getChildViewHolder(View child) on the RecyclerView:

@Override
public void onClick(View v) {
    MyHolder holder = (MyHolder) mRecyclerView.getChildViewHolder(v);
    holder.textView.setText("Clicked!");
}

Answer 3

@Override
public void onClick(View v) {
    int pos = getAdapterPosition(); //getPosition() is deprecated 
    notifyItemChanged(pos);
}

notifyItemChanged will notify your onBindViewHolder, then you can do something like this

public void onBindViewHolder(RoomViewHolder roomViewHolder, int i) {
    Room r = getItem(i);
    roomViewHolder.label.setText(r.name);
    if(i == pos){ // Do Something }

}

Whenever you click the item, it will change pos' value and trigger the // Do Something

Answer 4

Turn out that RecycleView saves the view position in the view layout params, so if you just want the view position from to get the right item from the list you can use this:

RecyclerView.LayoutParams lp = (RecyclerView.LayoutParams) v.getLayoutParams();
lp.getViewPosition();