Setting OnClickListener on RecyclerView itself not on item

Question

I want to set an OnClickListener on a RecyclerView, not on its items so that it triggers a click event when the user clicks on the RecyclerView (even if it is empty or full of items).

• I'm using MVVM
• I tried mRecyclerView.setClickable(true), not working

What I want

mRecyclerView.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        // do something
    }
});

My Adapter Class

public class TaskItemAdapter extends RecyclerView.Adapter<TaskItemAdapter.BaseItemAdapterViewHolder> {
    private static final String TAG = TaskItemAdapter.class.getSimpleName();
    private List<Task> mTaskList;
    private View.OnLongClickListener mOnLongClickListener;

    public TaskItemAdapter(List<Task> taskList, View.OnLongClickListener longClickListener) {
        mTaskList = taskList;
        mOnLongClickListener = longClickListener;
    }

    @NonNull
    @Override
    public BaseItemAdapterViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        if (parent instanceof RecyclerView) {
            int layoutId = R.layout.item_list_main;
            View view = LayoutInflater.from(parent.getContext()).inflate(layoutId, parent, false);
            view.setFocusable(true);
            return new BaseItemAdapterViewHolder(view);

        } else {
            throw new RuntimeException(TAG + "Not bound to recyclerView");
        }
    }

    @Override
    public void onBindViewHolder(@NonNull BaseItemAdapterViewHolder holder, int position) {
        Task task = mTaskList.get(position);
        holder.mItemTextView.setText("- " + task.getName());

        holder.itemView.setTag(task);
        holder.itemView.setOnLongClickListener(mOnLongClickListener);
    }

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

    public void loadItems(List<Task> taskList) {
        mTaskList = taskList;
        notifyDataSetChanged();
    }

    public class BaseItemAdapterViewHolder extends RecyclerView.ViewHolder {
        @BindView(R.id.item_textView)
        TextView mItemTextView;

        public BaseItemAdapterViewHolder(View view) {
            super(view);
            ButterKnife.bind(this, view);
        }
    }
}

Answer 1

mRecyclerView.addOnItemTouchListener(new RecyclerView.SimpleOnItemTouchListener() {
    @Override
    public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {
        return true;
    }
});

Then just handle the type of MotionEvent you want. Return true if you don't want the RecylerView doing anything else with it.

Answer 2

From View.OnTouchListener onTouch() press and release event. it is possible to trigger the views.

Answer 3

A RecyclerView does not provide OnClick callbacks by default. So you can create an OnTouchListener to consume click events.

public class RVClickHandler implements View.OnTouchListener {

    private RecyclerView mRecyclerView;
    private float mStartX;
    private float mStartY;

    public RVClickHandler(RecyclerView recyclerView) {
        mRecyclerView = recyclerView;
    }

    @Override
    public boolean onTouch(View v, MotionEvent event) {
        boolean isConsumed = false;
        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN: {
                mStartX = event.getX();
                mStartY = event.getY();
                break;
            }
            case MotionEvent.ACTION_UP: {
                float endX = event.getX();
                float endY = event.getY();
                if(detectClick(mStartX, mStartY, endX, endY)) {
                    //Ideally it would never be called when a child View is clicked.
                    //I am not so sure about this.
                    View itemView = mRecyclerView.findChildViewUnder(endX, endY);
                    if(itemView == null) {
                        //RecyclerView clicked
                        mRecyclerView.performClick();
                        isConsumed = true;
                    }
                }
                break;
            }
        }
        return isConsumed;
    }

    private static boolean detectClick(float startX, float startY, float endX, float endY) {
        return Math.abs(startX-endX) < 3.0 && Math.abs(startY-endY) < 3.0;
    }

}

add this to your RecyclerView as follows

recyclerView.setOnTouchListener(new RVClickHandler(recyclerView));

Now you can attach a normal OnClickListener to handle clicks.

recyclerView.setOnClickListener((v) -> {
    //Called when an empty space is clicked inside RecyclerView.
});

Click events for child views can be handled inside the ViewHolder