android - RecyclerView parent.notifyDataSet中的RecyclerView改变了子RecyclerView的松散位置

Question

我在 Vertical RecyclerView(如 Google Play Store)中使用 Horizo​​ntal RecyclerView 开发了一个 fragment 。

当我从父 RecyclerView 通知 DataSetChanged 时，子 RecyclerView 失去了位置，因为我认为 setAdapter 是在 onBindViewHolder 中调用的。此外，当我滚动到第一个水平回收 View 中的第 5 个位置时，如果我向下滚动并返回，我会松开第 5 个位置。

我尝试使用 RecyclerView.scrollToPosition() 但它不起作用。

所以我想我有两个解决方案:

• 一种方法(通过方法或设置)保持我的子回收器 View 的位置。 (最佳解决方案)

• 一种手动​​将 recyclerview 位置设置为刷新前的位置的方法。 (其他解决方案)

这是我的父适配器:

public class ProfilesCardViewListAdapter extends RecyclerView.Adapter<ProfilesCardViewListAdapter.ItemRowHolder> {
    private ArrayList<AidodysProfile> sectionsList;
    private Context context;
    private boolean[] isShown;
    private ProfileCardViewItemAdapter itemAdapters[];

    public ProfilesCardViewListAdapter(ArrayList<AidodysProfile> sectionsList, Context context) {

        this.sectionsList = sectionsList;
        this.context = context;
        this.isShown = new boolean[sectionsList.size()];
        this.itemAdapters = new ProfileCardViewItemAdapter[sectionsList.size()];
        for (int i = 0; i < sectionsList.size(); i++) {
            this.isShown[i] = true;
            this.itemAdapters[i] = new ProfileCardViewItemAdapter(sectionsList.get(i).getProfiles(), context, this);
        }
    }

    @Override
    public ItemRowHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_card_view_horizontal, null);
        final ItemRowHolder rowHolder = new ItemRowHolder(view);

        return rowHolder;
    }

    @Override
    public void onBindViewHolder(final ItemRowHolder holder, final int position) {
        String sectionName = sectionsList.get(position).getName();

        AidodysProfile[] sectionItems = sectionsList.get(position).getProfiles();

        holder.sectionTitle.setTextSize(context.getResources().getDimension(R.dimen.text_size_profileslist_section_title));
        holder.sectionButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                showHideSection(holder, position);
            }
        });

        if (isShown[position]) {
            holder.itemRecyclerView.setVisibility(View.VISIBLE);
            holder.sectionButton.setText(context.getString(R.string.action_profiles_section_hide));
        } else {
            holder.itemRecyclerView.setVisibility(View.GONE);
            holder.sectionButton.setText(context.getText(R.string.action_profiles_section_show));
        }

        if (!sectionsList.get(position).isLeaf()) { // FOLDER
            if (sectionName.equals("")) {
                holder.sectionTitle.setVisibility(View.GONE);
                holder.sectionButton.setVisibility(View.GONE);
            } else {
                holder.sectionTitle.setVisibility(View.VISIBLE);
                holder.sectionButton.setVisibility(View.VISIBLE);
            }
            holder.sectionTitle.setText(sectionName);
        } else { // PROFILE
            return;
        }

        holder.itemRecyclerView.setHasFixedSize(true);
        holder.itemRecyclerView.setLayoutManager(new LinearLayoutManager(context, LinearLayoutManager.HORIZONTAL, false));
        holder.itemRecyclerView.setAdapter(itemAdapters[position]);

    }

    private void showHideSection(ItemRowHolder holder, int position) {
        if (holder.itemRecyclerView.getVisibility() == View.VISIBLE) {
            isShown[position] = false;
            holder.itemRecyclerView.setVisibility(View.GONE);
            holder.sectionButton.setText(context.getText(R.string.action_profiles_section_show));
        } else {
            isShown[position] = true;
            holder.itemRecyclerView.setVisibility(View.VISIBLE);
            holder.sectionButton.setText(context.getString(R.string.action_profiles_section_hide));
        }
    }

    @Override
    public int getItemCount() {
        return (sectionsList != null ? sectionsList.size() : 0);
    }

    public class ItemRowHolder extends RecyclerView.ViewHolder {

        protected TextView sectionTitle;
        protected RecyclerView itemRecyclerView;
        protected Button sectionButton;

        public ItemRowHolder(View view) {
            super(view);
            this.sectionTitle = (TextView) view.findViewById(R.id.section_title);
            this.itemRecyclerView = (RecyclerView) view.findViewById(R.id.item_recycler_view);
            this.sectionButton = (Button) view.findViewById(R.id.section_button);
        }

    }
}

子适配器:

class ProfileCardViewItemAdapter extends RecyclerView.Adapter<ProfileCardViewItemAdapter.SingleItemRowHolder> {
    private AidodysProfile[] itemsList;
    private CurrentUser currentUser;
    private Context context;
    private int selectedPos = -1;
    private ProfilesCardViewListAdapter parent;

    public ProfileCardViewItemAdapter(AidodysProfile[] itemsList, Context context, ProfilesCardViewListAdapter parent) {
        this.itemsList = itemsList;
        this.context = context;
        this.parent = parent;
        this.currentUser = CurrentUser.getInstance(context);
    }

    @Override
    public SingleItemRowHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item_card_view_horizontal, null);
        SingleItemRowHolder rowHolder = new SingleItemRowHolder(view);
        return (rowHolder);
    }

    @Override
    public void onBindViewHolder(final SingleItemRowHolder holder, final int position) {
        AidodysProfile profile = itemsList[position];

        holder.itemCardView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                selectProfile(holder, position);
            }
        });

        if (profile.equals(currentUser.getProfile())) {
            selectedPos = position;
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                holder.itemCardView.setCardBackgroundColor(context.getColor(R.color.aidodysRed));
            } else {
                holder.itemCardView.setCardBackgroundColor(context.getResources().getColor(R.color.aidodysRed));
            }
        } else {
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                holder.itemCardView.setCardBackgroundColor(context.getColor(R.color.white));
            } else {
                holder.itemCardView.setCardBackgroundColor(context.getResources().getColor(R.color.white));
            }
        }

        holder.itemTitle.setText(profile.getName());

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            holder.itemPicture.setImageDrawable(context.getDrawable(R.drawable.ic_sheet_smile_black_48dp));
            holder.button1.setImageDrawable(context.getDrawable(R.drawable.ic_edit_black_24dp));
            holder.button2.setImageDrawable(context.getDrawable(R.drawable.ic_look_profile));
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                holder.itemTitle.setTextAppearance(R.style.Aidodys_Text_ProfilesList_Item);
                holder.itemPicture.setColorFilter(context.getColor(R.color.white));
                holder.topParts.setBackgroundColor(context.getColor(R.color.aidodysRed));
            } else  {
                holder.itemTitle.setTextColor(context.getResources().getColor(R.color.white));
                holder.itemTitle.setTextSize(context.getResources().getDimension(R.dimen.text_size_profileslist_item));
                holder.itemPicture.setColorFilter(context.getResources().getColor(R.color.white));
                holder.topParts.setBackgroundColor(context.getResources().getColor(R.color.aidodysRed));
            }
        } else {
            holder.button1.setImageDrawable(context.getResources().getDrawable(R.drawable.ic_edit_black_24dp));
            holder.button2.setImageDrawable(context.getResources().getDrawable(R.drawable.ic_look_profile));
            holder.itemTitle.setTextColor(context.getResources().getColor(R.color.white));
            holder.itemTitle.setTextSize(context.getResources().getDimension(R.dimen.text_size_profileslist_item));
            holder.itemPicture.setImageDrawable(context.getResources().getDrawable(R.drawable.ic_sheet_smile_black_48dp));
            holder.itemPicture.setColorFilter(context.getResources().getColor(R.color.white));
            holder.topParts.setBackgroundColor(context.getResources().getColor(R.color.aidodysRed));
        }
    }

    private void selectProfile(SingleItemRowHolder holder, int position) {
        SharedPreferences.Editor editor = context.getSharedPreferences("Aidodys", 0).edit();
        editor.putString("profile", new Gson().toJson(itemsList[position]));
        editor.apply();
        currentUser.setProfile(itemsList[position]);
        parent.notifyDataSetChanged();
        notifyDataSetChanged();
        ((RecyclerView)holder.itemCardView.getParent()).scrollToPosition(position);
        selectedPos = position;
    }

    @Override
    public int getItemCount() {
        return (itemsList != null ? itemsList.length : 0);
    }

    public class SingleItemRowHolder extends RecyclerView.ViewHolder {

        protected TextView itemTitle;
        protected ImageView itemPicture;
        protected CardView itemCardView;
        protected ImageView button1;
        protected ImageView button2;
        protected LinearLayout topParts;

        public SingleItemRowHolder(View view) {
            super(view);

            this.itemTitle = (TextView)view.findViewById(R.id.item_title);
            this.itemPicture = (ImageView)view.findViewById(R.id.item_picture);
            this.itemCardView = (CardView)view.findViewById(R.id.card_view_list_item);
            this.topParts = (LinearLayout)view.findViewById(R.id.card_view_list_item_top_part);
            this.button1 = (ImageView)view.findViewById(R.id.item_button_1);
            this.button2 = (ImageView)view.findViewById(R.id.item_button_2);
        }
    }
}

如果有人对我有解决方案

谢谢

Answer 1

将 x 滚动偏移量存储在 SparseArray 中用于位置并在绑定(bind) View 持有者时恢复。

public class ProfilesCardViewListAdapter extends RecyclerView.Adapter<ProfilesCardViewListAdapter.ItemRowHolder> {

    private SparseIntArray sparseArray = new SparseIntArray();

    @Override
    public void onBindViewHolder(final ItemRowHolder holder, final int position) {

        // Use srollBy for animate scrolling
        holder.itemRecyclerView.srollBy(sparseArray.get(position, 0), 0);
        // Or scrollTo for restore previous x offset
        //holder.itemRecyclerView.srollTo(sparseArray.get(position, 0), 0);

        holder.itemRecyclerView.setOnScrollListener(new RecyclerView.OnScrollListener() {

           @Override
           public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
               sparseArray.put(position, dx);
           }
        }
    }
}