RecyclerView在onCreateViewHolder而非onBindViewHolder处设置onclick事件

Question

I'm pretty new to Android and is faced with a problem here.

I have recently switched to using recycler view instead of listview in one of my activities named activity_drinks_menu for displaying menus of drinks.

What is supposed to be happening is this:

I click on one of the items (holder.layout is clicked), it should "expand" to show more options related to it. I could press on one of the options in these list of options. When I do so, a popup window (activityforresult) appears and the option that I newly chose gets reflected to my Drinks object. The options list is still "expanded" in case I want to edit more options for that specific item.

Everything works fine until I see the popup window (activityforresult), get the result back from the activity, reflect it to the Drinks object. After this Drinks object has been updated, as I have mentioned above, the options list MUST still be "expanded", showing all the options available for me to tweek with. However, it gets "closed".

I am guessing this is because of the way how my code is written but could not figure out a brilliant way to resolve this problem. Here's my code:

package com.bringit.bringitrecyclerviewtest;

import android.app.Activity;
import android.content.Context;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.TextView;

import com.sothree.slidinguppanel.SlidingUpPanelLayout;

import java.util.ArrayList;

/**
 * Customized adapter for RecyclerView
 */

public class DrinkMenuItem extends RecyclerView.Adapter<DrinkMenuItem.ViewHolder> {
    private Context context;
    private ViewGroup parent;
    private ArrayList<Drink> menu;
    private ArrayList<DrinkSelected> selected;
    private DrinkMenuBasketItem selectedAdapter;

    private DrinkMenuDropdownItem dropdownAdapter;

    public static class ViewHolder extends RecyclerView.ViewHolder {
        public LinearLayout layout;
        public TextView name, price;
        public ListView dropdown;
        public Button basket;
        public boolean tabbed = false;

        public ViewHolder(View itemView) {
            super(itemView);
            layout = (LinearLayout)itemView.findViewById(R.id.drink_menu_layout);
            name = (TextView)itemView.findViewById(R.id.drink_menu_name);
            price = (TextView)itemView.findViewById(R.id.drink_menu_price);
            dropdown = (ListView)itemView.findViewById(R.id.drink_menu_dropdown_list);
            basket = (Button)itemView.findViewById(R.id.drink_menu_basket_button);
        }
    }

    public DrinkMenuItem(Context context, ArrayList<Drink> menu, ArrayList<DrinkSelected> selected, DrinkMenuBasketItem selectedAdapter) {
        this.context = context;
        this.menu = menu;
        this.selected = selected;
        this.selectedAdapter = selectedAdapter;
        this.dropdownAdapter = null;
    }

    public void updateDropdown(int requestedOption, int responsedOptionitem) {
        dropdownAdapter.updateSelectedOption(requestedOption, responsedOptionitem);
        notifyDataSetChanged();
    }

    // Create new views (invoked by the layout manager)
    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        this.parent = parent;
        View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_drink_menu, parent, false);

        return new ViewHolder(itemView);
    }

    // Replace the contents of a view (invoked by the layout manager)
    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        final Drink d = menu.get(position);
        holder.name.setText(d.getName());
        holder.price.setText(d.getPrice() + d.totalAdditionalPrice() + "원");

        setOnClickEvent(holder, position, parent);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

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

    private void setOnClickEvent(final ViewHolder holder, final int position, final ViewGroup parent) {
        holder.layout.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (!holder.tabbed) {
                    //make dropdown
                    dropdownAdapter = new DrinkMenuDropdownItem(context, menu, position, holder.price);
                    holder.dropdown.setAdapter(dropdownAdapter);
                    setListViewHeight(holder.dropdown);

                    //set dropdown-related stuff
                    holder.tabbed = true;
                    holder.basket.setVisibility(View.VISIBLE);

                   ((RecyclerView) parent).smoothScrollToPosition(position);
            }
            else {
                Log.d("dropdown", "is this being called when options is changed? 1");
                //delete dropdown
                holder.dropdown.setAdapter(null);
                menu.get(position).returnToUnselected();
                holder.price.setText(menu.get(position).getPrice() + "원");
                setListViewHeight(holder.dropdown);

                //reset dropdown-related stuff
                holder.tabbed = false;
                holder.basket.setVisibility(View.GONE);
            }
        }
    });

    holder.basket.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Drink d = menu.get(position);
            boolean doesExist = false; int i = 0;

            //checking if already in the list
            for(DrinkSelected ds : selected) {
                //the same entry if the name and option are the same
                if(ds.getName().equals(d.getName()) && ds.getOption().equals(d.printOptionForSelected())) {
                    doesExist = true;
                    i = selected.indexOf(ds);
                    break;
                }
            }

            if(doesExist) {
                selected.get(i).setCount(selected.get(i).getCount()+d.getCount());
                selected.get(i).setPrice(selected.get(i).getPrice()+(d.getPrice()+d.totalAdditionalPrice()));
            }
            else {
                    selected.add(new DrinkSelected(d.getName(), d.getCount(), d.getPrice() + d.totalAdditionalPrice(), d.printOptionForSelected()));
                }

                selectedAdapter.notifyDataSetChanged();

                holder.dropdown.setAdapter(null);
                menu.get(position).returnToUnselected();
                holder.price.setText(menu.get(position).getPrice() + "원");

                setListViewHeight(holder.dropdown);

                //set basket button gone
                holder.basket.setVisibility(View.GONE);
            }
        });
    }

    private void setListViewHeight(final ListView l) {
        ViewGroup.LayoutParams params = l.getLayoutParams();

        if(l.getAdapter() == null) {
            params.height = 0;
        }
        else {
            int numberOfItems = l.getAdapter().getCount();

            // Get total height of all items.
            int totalItemsHeight = 0;
            for (int itemPos = 0; itemPos < numberOfItems; itemPos++) {
                View item = l.getAdapter().getView(itemPos, null, l);
                item.measure(0, 0);
                totalItemsHeight += item.getMeasuredHeight();
            }

            // Get total height of all item dividers.
            int totalDividersHeight = l.getDividerHeight() * (numberOfItems - 1);    

            // Set list height.
            params.height = totalItemsHeight + totalDividersHeight;
        }

        l.setLayoutParams(params);

        l.requestLayout();
        }
    }

As the code shows, I need to have the information about the position of the item in order to display the correct options in my dropdown list. Therefore, I cannot setOnClickEvents in my onCreateViewHolder method, because there is no way for me to know which position it is for.

But then because I am "resetting" my onClickEvents every time the ViewHolder object gets binded to the itemView, I think this error is occurring. Could anyone help me out here?

Answer 1

here is the custom class I use to enable onclick from

in your activity

RecyclerView drawerList = (RecyclerView) findViewById(R.id.DrawerList);
drawerList.setLayoutManager(new LinearLayoutManager(this)); 

// pass context , implement click listener interface
    drawerList.addOnItemTouchListener(new RecycleOntouchListener(Home.this, new ClickListener() {
                @Override
                public void OnClick(View view, int position) {
                    SelectItem(position);
                }
            }));

custom class to handle on touch

public class RecycleOntouchListner implements RecyclerView.OnItemTouchListener {

        private GestureDetector mGestureDetector;
        private ClickListener mClickListner;

        public RecycleOntouchListner(Context mContext,  ClickListener clickListner) {

            this.mClickListner = clickListner;
            mGestureDetector = new GestureDetector(mContext, new GestureDetector.SimpleOnGestureListener() {
                @Override
                public boolean onSingleTapUp(MotionEvent e) {

                    return true;
                }
            });
        }


        @Override
        public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {

            View child = rv.findChildViewUnder(e.getX(), e.getY());
            if (child != null && mClickListner != null && mGestureDetector.onTouchEvent(e)) {
                mClickListner.OnClick(child, rv.getChildAdapterPosition(child));
                return false;

            }
            return false;
        }

        @Override
        public void onTouchEvent(RecyclerView rv, MotionEvent e) {

        }

        @Override
        public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {

        }
    }

interface to handle click

public interface ClickListener {
    void OnClick(View view, int position);
}