RecyclerView滚动时数据值自动变化的问题

Question

我附上了一张图片来帮助你理解我的问题。

我正在制作健身应用程序。

按下按钮时，添加例程在添加的例程中，可以再次使用按钮添加详细数据（组、磅、次数）。

所以，我正在使用 two type RecyclerView（页脚除外）。

我使用 DiffUtil 来更新正在添加的项目。

我在做测试的时候发现了一个奇怪的现象。（见图）

这不是一个错误，所以我不知道它出了什么问题。

输入数据后，在添加多个明细项时，输入数据的值先出现在后面添加的项中。

如果我在添加许多项目后滚动，数据会随机移动。

但是，当你添加很多项目或滚动时，这种现象是意料之中的。

怎么了？

RoutineAdapter.java

public class RoutineAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
    final static int TYPE_ROUTINE = 1;
    final static int TYPE_ROUTINE_DETAIL = 2;
    final static int TYPE_ROUTINE_FOOTER = 3;

    private Context context;
    private List<Object> mItems = new ArrayList<>();
    OnRoutineItemClickListener routinelistener;
    OnRoutineAddClickListener routineAddListener;

    public void updateRoutineList(List<Object> newRoutineList) {
        final RoutineDiffUtil diffCallback = new RoutineDiffUtil(this.mItems, newRoutineList);
        final DiffUtil.DiffResult diffResult = DiffUtil.calculateDiff(diffCallback);

        this.mItems.clear();
        this.mItems.addAll(newRoutineList);
        diffResult.dispatchUpdatesTo(this);
    }

    @NonNull
    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        context = parent.getContext();
        View itemView;
        if(viewType == TYPE_ROUTINE){
            itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.routine_item, parent, false);
            return new RoutineViewHolder(itemView);
        }
        else if(viewType == TYPE_ROUTINE_DETAIL){
            itemView = LayoutInflater.from(context).inflate(R.layout.routine_detail_item, parent, false);
            return new RoutineDetailViewHolder(itemView);
        }
        else {
            itemView = LayoutInflater.from(context).inflate(R.layout.add_routine_item, parent, false);
            return new RoutineAddFooterViewHolder(itemView);
        }
    }

    @Override
    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
        Object obj;
        switch (getItemViewType(position)) {
            case TYPE_ROUTINE:
                obj = mItems.get(position);
                setRoutineData((RoutineViewHolder) holder, (RoutineModel) obj);
                break;
            case TYPE_ROUTINE_DETAIL:
                obj = mItems.get(position);
                RoutineDetailModel item = (RoutineDetailModel) obj;
                ((RoutineDetailViewHolder) holder).setDetailItem(item);
                break;
            case TYPE_ROUTINE_FOOTER:
                break;
        }
    }
    
    @Override
    public int getItemCount() {
        if(mItems == null)
            return -1;
        return mItems.size() + 1; // for footer
    }

    @Override
    public int getItemViewType(int position) {
        if(position == mItems.size()) {
            return TYPE_ROUTINE_FOOTER;
        }
        else {
            Object obj = mItems.get(position);
            if(obj instanceof RoutineModel) {
                return TYPE_ROUTINE;
            }
            else {
                // obj instanceof RoutineDetailModel
                return TYPE_ROUTINE_DETAIL;
            }
        }
    }
    
    // add routine interface
    public interface OnRoutineAddClickListener {
        public void onAddRoutineClick();
    }

    public void setOnAddRoutineClickListener(OnRoutineAddClickListener listener) {
        this.routineAddListener = listener;
    }
    
    // details add / remove interface
    public interface OnRoutineItemClickListener {
        public void onAddBtnClicked(int curRoutinePos);
        public void onDeleteBtnClicked(int curRoutinePos);
        public void onWritingCommentBtnClicked(int curRoutinePos);
    }

    public void setOnRoutineClickListener(OnRoutineItemClickListener listener) {
        this.routinelistener = listener;
    }

    private class RoutineViewHolder extends RecyclerView.ViewHolder {
        public TextView routine;
        public Button addSet;
        public Button deleteSet;
        public Button comment;

        public RoutineViewHolder(@NonNull View itemView) {
            super(itemView);

            initViews();

            addSet.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    if(routinelistener != null && getAdapterPosition() != RecyclerView.NO_POSITION)
                        routinelistener.onAddBtnClicked(getAdapterPosition());
                }
            });

            deleteSet.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    if(routinelistener != null && getAdapterPosition() != RecyclerView.NO_POSITION)
                        routinelistener.onDeleteBtnClicked(getAdapterPosition());
                }
            });

            comment.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    if(routinelistener != null && getAdapterPosition() != RecyclerView.NO_POSITION)
                        routinelistener.onWritingCommentBtnClicked(getAdapterPosition());
                }
            });
        }
    }

    private class RoutineDetailViewHolder extends RecyclerView.ViewHolder {
        public TextView set;
        public TextView weight;

        public RoutineDetailViewHolder(@NonNull View itemView) {
            super(itemView);
            initViews();
        }

        private void initViews() {
            set = itemView.findViewById(R.id.set);
            weight = itemView.findViewById(R.id.weight);
        }

        private void setDetailItem(RoutineDetailModel item) {
            set.setText(item.getSet().toString() + "set");
        }
    }
}

RoutineDiffUtil.java

public class RoutineDiffUtil extends DiffUtil.Callback {
    private List<Object> oldRoutineList;
    private List<Object> newRoutineList;

    public RoutineDiffUtil(List<Object> oldRoutineList, List<Object> newRoutineList) {
        this.oldRoutineList = oldRoutineList;
        this.newRoutineList = newRoutineList;
    }

    @Override
    public int getOldListSize() {
        return oldRoutineList.size();
    }

    @Override
    public int getNewListSize() {
         return newRoutineList.size();
    }

    @Override
    public boolean areItemsTheSame(int oldItemPosition, int newItemPosition) {
        Object oldObj = oldRoutineList.get(oldItemPosition);
        Object newObj = newRoutineList.get(newItemPosition);
        if (oldObj instanceof RoutineModel && newObj instanceof RoutineModel) {
            return ((RoutineModel) oldObj).id == ((RoutineModel) newObj).id;
        }
        else if (oldObj instanceof RoutineDetailModel && newObj instanceof RoutineDetailModel) {
            return ((RoutineDetailModel) oldObj).id == ((RoutineDetailModel) newObj).id;
        }
        else if(oldObj instanceof RoutineModel && newObj instanceof RoutineDetailModel) {
            return false;
        }
        else {
            return false;
        }
    }

    @Override
    public boolean areContentsTheSame(int oldItemPosition, int newItemPosition) {
        return (oldRoutineList.get(oldItemPosition)).equals(newRoutineList.get(newItemPosition));
    }
}

RoutineDetailModel.java

public class RoutineDetailModel {
    public int id;
    private int set = 1;
    private int weight;

    public RoutineDetailModel() {
        Random random = new Random();
        this.id = random.nextInt();
    }

    public RoutineDetailModel(int set) {
        Random random = new Random();
        this.id = random.nextInt();
        this.set = set+1;
    }
    public Integer getSet() {
        return set;
    }

    public int getId() {
        return id;
    }
    @Override
    public int hashCode() {
        return Objects.hash(set, weight);
    }

    @Override
    public boolean equals(@Nullable Object obj) {
        if(obj != null && obj instanceof RoutineDetailModel) {
            RoutineDetailModel model = (RoutineDetailModel) obj;
            if(this.id == model.getId()) {
                return true;
            }
        }
        return false;
    }
}

Answer 1

首先，您应该将 ListAdapter class 与 diff util 一起使用。您的适配器的问题在于，Recycler 视图一次又一次地回收视图。也就是说，当您为第一个项目输入文本时，此项目用于其他视图。要在任何文本更改后解决它，您应该将此文本保留在模型中 class 然后您应该将此文本设置为 onBind() 方法中的字段。总而言之，回收站视图对不同的项目使用相同的视图，因此与任何项目相关的任何数据都应保存在模型中，并且模型应设置为 onBind() 中的视图。

RecyclerView滚动时数据值自动变化的问题

Problem of automatic change of data value when scrolling in RecyclerView

android

android-recyclerview

android-diffutils