[Android Studio] Java Recylerview 뷰페이징

일반 리사이클러 뷰와 동일하나, 중간에

recyclerView.addOnScrollListener를 추가해 주고 

리사이클러뷰에 마지막 아이템에 도달했을때 어댑터에 아이템을 추가해주는 기능을 구현하면 된다.

아래 코드에서는 10개씩 불러오는 것으로 했다.

1.

WinningHistoryActivity

package org.techtown.lottoworld.winningHistory;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import android.os.Bundle;

import org.techtown.lottoworld.DataAdapter;
import org.techtown.lottoworld.NumberQuery;
import org.techtown.lottoworld.R;

import java.sql.SQLException;
import java.util.List;

public class WinningHistoryActivity extends AppCompatActivity {
    static public List<NumberQuery> numberQueryList;
    int pages; // 전체 페이지 수
    int totalItem;
    int page = 0; // 현재 페이지

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_winning_history);
        RecyclerView recyclerView = findViewById(R.id.recyclerView_ph);

	//아이템을 DB에서 읽어오는 부분
        getNumberQueryList();

        LinearLayoutManager layoutManager = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false);
        recyclerView.setLayoutManager(layoutManager);
	//Adapter를 선언
        WinningNumAdapter adapter = new WinningNumAdapter();

        totalItem = numberQueryList.size();


        if (totalItem % 10 == 0) { // 전체 페이지 계산 10개씩 페이징하는 경우
            pages = totalItem / 10;
        } else {
            pages = totalItem / 10 + 1;
        }
	// 먼저 아이템을 추가해주는 부분
        addNumItem(adapter);
	// 리사이클러 뷰에 어뎁터 등록
        recyclerView.setAdapter(adapter);
	// 리사이클러뷰에 스크롤을 하면 마지막 아이템이 왔을때 아이템을 추가
        recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
            @Override
            public void onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState) {
                super.onScrollStateChanged(recyclerView, newState);
            }

            @Override
            public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
                super.onScrolled(recyclerView, dx, dy);

                int lastPosition = ((LinearLayoutManager) recyclerView.getLayoutManager()).findLastCompletelyVisibleItemPosition();
                int totalCount = recyclerView.getAdapter().getItemCount();

                if (lastPosition == totalCount - 1) {
                    //아이템을 추가하고 다시 새로 고침
                    addNumItem(adapter);
                    adapter.notifyDataSetChanged();
                }
            }
        });
    }
    
	// 아이템을 읽어오는 메소드
    public int getNumberQueryList() {
        int round = 0;
        try {
            DataAdapter mDbAdapter = new DataAdapter(getApplicationContext());
            mDbAdapter.open();

            // db에 있는 값들을 model을 적용해서 넣는다.
            numberQueryList = mDbAdapter.getWinningData();
            // db 닫기
            mDbAdapter.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return round;
    }

    public void addNumItem(WinningNumAdapter adapter) {

        int start = page * 10;
        int end;

        if (totalItem < (page + 1) * 10) {
            end = totalItem;
        } else {
            end = (page + 1) * 10;
        }

        for (int i = start; i < end; i++) {
            adapter.addItem(numberQueryList.get(i));
        }
        page++;

    }
}

 

2.

WinningNumAdapter

package org.techtown.lottoworld.winningHistory;

import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

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

import org.techtown.lottoworld.NumberQuery;
import org.techtown.lottoworld.R;

import java.util.ArrayList;

public class WinningNumAdapter extends RecyclerView.Adapter<WinningNumAdapter.ViewHolder>{
    ArrayList<NumberQuery> items = new ArrayList<NumberQuery>();

    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        LayoutInflater inflater = LayoutInflater.from(parent.getContext());
        View itemView = inflater.inflate(R.layout.winning_num_item, parent,false);

        return new ViewHolder(itemView);
    }

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

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


    public void addItem(NumberQuery item) {
        items.add(item);
    }

    public void setItems(ArrayList<NumberQuery> items) {
        this.items = items;
    }

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

    public void setItem(int position, NumberQuery item) {
        items.set(position, item);
    }
    static class ViewHolder extends RecyclerView.ViewHolder{

        TextView round;
        TextView winningNums;
        TextView bonusNum;
        TextView statics;

        public ViewHolder(@NonNull View itemView) {
            super(itemView);
            round = itemView.findViewById(R.id.round);
            winningNums = itemView.findViewById(R.id.winningNums);
            bonusNum = itemView.findViewById(R.id.bonusNum);
            statics = itemView.findViewById(R.id.statics);

        }
        public void setItem(NumberQuery item) {
            String roundT = item.getRound() + "회 당첨번호";
            String staticT = "총합:" + item.getTotal() + " 짝홀:" + item.getEven() + "/" +  (6 - item.getEven());


            round.setText(roundT);
            winningNums.setText(item.numberString());
            bonusNum.setText(Integer.toString(item.getNums()[6]));

            statics.setText(staticT);
        }


    }
}