向下或向上滑动时在 android 回收站视图中丢失所选项目

Question

I made a recycler view to show and choose Instagram posts, in recycler view adapter I handled onclick to show user if items are selected or not and handling sum of chosen posts... but there is problem when insta post in adapter become more than 12 when i scroll in page some chosen items are shown as not chosen, and some posts that are not choosed they look like you choosed them?:! can any one help me ? here is my adapter:

package com.example.pinstagram.adaptor;

import android.content.Context;
import android.os.Build;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.Toast;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

import com.example.pinstagram.R;
import com.example.pinstagram.classes.BuyBasketFlow;
import com.example.pinstagram.classes.InstaPosts;
import com.example.pinstagram.classes.SellingItems;
import com.example.pinstagram.viewHolders.InstaPostsRecyclerViewHolders;
import com.squareup.picasso.Picasso;

import java.util.ArrayList;
import java.util.List;


public class InstaPostsRecyclerViewAdapter extends RecyclerView.Adapter<InstaPostsRecyclerViewHolders> {
    private List<InstaPosts> instaList;
    private List<InstaPosts> selectedPosts;
    LinearLayout linearLayout;
    private Context context;
    TextView numberTextView,eachPostPriceTxt,totalPriceTxt;
    BuyBasketFlow buyBasketFlow;
    SellingItems sellingItems;

    public InstaPostsRecyclerViewAdapter(Context context, List<InstaPosts> itemList,List<InstaPosts> selectedPosts,LinearLayout linearLayout,TextView[] textViews) {
        this.instaList = itemList;
        this.context = context;
        this.selectedPosts = selectedPosts;
        this.linearLayout = linearLayout;
        numberTextView = textViews[0];
        eachPostPriceTxt = textViews [1];
        buyBasketFlow = new BuyBasketFlow();
        sellingItems = new SellingItems();
        selectedPosts.clear();
        for(int i = 0; i < instaList.size();i++){
            instaList.get(i).setSelected(false);
        }
        linearLayout.setVisibility(View.GONE);
    }

    @NonNull
    @Override
    public InstaPostsRecyclerViewHolders onCreateViewHolder(ViewGroup parent, int viewType) {
        View layoutView = LayoutInflater.from(parent.getContext()).inflate(R.layout.isnta_posts_listview, null);
        InstaPostsRecyclerViewHolders crcv = new InstaPostsRecyclerViewHolders(layoutView);
        return crcv;
    }
    @Override
    public void onBindViewHolder(@NonNull final InstaPostsRecyclerViewHolders holder, final int position) {
        holder.cardView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Log.i("Log3", " item number: " + position + " is clicked");
                instaList.get(position).setSelected(!instaList.get(position).isSelected());
                if(buyBasketFlow.getType().compareTo("like")==0) {
                    if (instaList.get(position).isCanBeSelect()) {
                        selectingPhase(holder,position);

                    } else {
                        Toast.makeText(context, R.string.just_select_photo, Toast.LENGTH_SHORT).show();
                        Log.i("Log1", instaList.get(position).getTypename());
                    }
                }else if(buyBasketFlow.getType().compareTo("view")==0){
                    if (instaList.get(position).isViewCanBeSelected()) {
                        selectingPhase(holder,position);

                    } else {
                        Toast.makeText(context, R.string.just_select_video, Toast.LENGTH_SHORT).show();
                        Log.i("Log1", instaList.get(position).getTypename());
                    }

                }else if(buyBasketFlow.getType().compareTo("comment")==0){
                    if (instaList.get(position).isViewCanBeSelected()||instaList.get(position).isCanBeSelect()) {
                        selectingPhase(holder,position);

                    } else {
                        Toast.makeText(context, R.string.just_select_video, Toast.LENGTH_SHORT).show();
                        Log.i("Log1", instaList.get(position).getTypename());
                    }
                }
            }
        });

        Picasso.get().load(instaList.get(position).getThumbnail_url()).into(holder.instaImage);
    }
    public List<InstaPosts> getSelectedPosts(){
        return selectedPosts;
    }

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

    private void selectingPhase(InstaPostsRecyclerViewHolders holder,int position){
        if (instaList.get(position).isSelected()) {
            selectedPosts.add(instaList.get(position));
            buyBasketFlow.setPostsArrays(selectedPosts);
            for (InstaPosts selected : selectedPosts) {
                Log.e("Log1", selected.toString());
            }
            holder.radioBtn.setImageDrawable(context.getDrawable(R.drawable.radio_button_checked));
            holder.cardView.setStrokeWidth(10);
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                holder.cardView.setStrokeColor(context.getColor(R.color.colorPrimary));
            }
        } else {
            selectedPosts.remove(instaList.get(position));
            buyBasketFlow.setPostsArrays(selectedPosts);
            for (InstaPosts selected : selectedPosts) {
                Log.e("Log1", selected.toString());
            }
            holder.cardView.setStrokeWidth(0);
            holder.radioBtn.setImageDrawable(context.getDrawable(R.drawable.radio_button_unchecked));
        }
        if (selectedPosts.size() < 1) {
            linearLayout.setVisibility(View.GONE);
            Log.i("Log1", "layout must become invisible");

        } else {
            Log.i("Log1", "layout must become visible");
            linearLayout.setVisibility(View.VISIBLE);
            sellingItems = buyBasketFlow.getSellingItem();
            numberTextView.setText("" + selectedPosts.size());
            Log.i("Log1", "" + Integer.parseInt(sellingItems.getPrice()));
            String text = "قیمت هر پست" + sellingItems.getPrice() + " تومان ";
            String sum = Integer.toString((selectedPosts.size() * Integer.parseInt(sellingItems.getPrice())));
            text = text + "و قیمت مجموع " + sum + " تومان ";
            eachPostPriceTxt.setText(text);
        }
    }
}

Answer 1

You need to set selected state on onBindViewHolder every time.

In onBindViewHolder:

InstaPosts instaPosts = instaList.get(position);
holder.cardView.setStrokeWidth(instaPosts.isSelected() ? 10 : 0);
holder.radioBtn.setImageDrawable(context.getDrawable(instaPosts.isSelected() ? R.drawable.radio_button_checked : R.drawable.radio_button_unchecked));