안드로이드 RecyclerView 예제

- androidx 기준
- 클릭 이벤트, Diffutil 구현 샘플


1. app module dependencies 설정
2019.02.27 기준
implementation 'androidx.recyclerview:recyclerview-selection:1.0.0'

레퍼런스 : https://developer.android.com/jetpack/androidx/migrate





2. DiffUtil.Callback 작성

- DiffUtilCallback
public class DiffUtilCallback extends DiffUtil.Callback {
    private final List<TextItem> oldList;
    private final List<TextItem> newList;

    public DiffUtilCallback(List<TextItem> oldList, List<TextItem> newList) {
        this.oldList = oldList;
        this.newList = newList;
    }

    @Override
    public int getOldListSize() {
        return oldList == null ? 0 : oldList.size();
    }

    @Override
    public int getNewListSize() {
        return newList == null ? 0 : newList.size();
    }

    @Override
    public boolean areItemsTheSame(int oldItemPosition, int newItemPosition) {
        return oldList.get(oldItemPosition).getId() == newList.get(newItemPosition).getId();
    }

    @Override
    public boolean areContentsTheSame(int oldItemPosition, int newItemPosition) {
        return oldList.get(oldItemPosition).getText().equals(newList.get(newItemPosition).getText());
    }
}






3. RecyclerView.Adapter 구현

- TextItemAdapter
public abstract class TextItemAdapter extends RecyclerView.Adapter<Holder> implements View.OnClickListener {
    private final List<TextItem> list = new ArrayList<>();

    @Override
    public void onClick(View v) {
        ViewParent parent = v.getParent();

        if (parent instanceof RecyclerView) {
            RecyclerView rv = (RecyclerView) parent;

            // 클릭된 포지션 찾기
            int position = rv.getChildAdapterPosition(v);

            TextItem item = list.get(position);
            onItemClick(rv, v, position, item);
        }
    }

    /**
     * 클릭 이벤트
     *
     * @param rv
     * @param view
     * @param position
     * @param item
     */
    public abstract void onItemClick(RecyclerView rv, View view, int position, TextItem item);

    @NonNull
    @Override
    public Holder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(android.R.layout.simple_list_item_1, parent, false);
        // 클릭 이벤트
        view.setOnClickListener(this);
        return new Holder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull Holder holder, int position) {
        holder.bindItem(list.get(position));
    }

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

    public void updateList(List<TextItem> newList) {

        // 리스트 갱신
        DiffUtilCallback diffUtilCallback = new DiffUtilCallback(list, newList);
        DiffUtil.DiffResult result = DiffUtil.calculateDiff(diffUtilCallback);

        this.list.clear();
        this.list.addAll(newList);

        result.dispatchUpdatesTo(this);
    }
}



4. 샘플코드
소스코드
APK