Question

我有一个RecyclerView，其中包含Horizontal RecyclerView和Vertical Recyclerview。我对如何同时管理两者的数据模型感到困惑。这是我的代码，后跟此example

public class HomeAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {

    private final int VIEW_TYPE_DESIGN_TYPES = 0;
    private final int VIEW_TYPE_DESIGNS = 1;

    private Context context;
    private ArrayList<Object> feeds;

    public HomeAdapter(Context context, ArrayList<Object> feeds) {
        this.context = context;
        this.feeds = feeds;
    }

    @Override
    public int getItemViewType(int position) {
        if (position == 0)
            return VIEW_TYPE_DESIGN_TYPES;
        if (position == 1)
            return VIEW_TYPE_DESIGNS;
        return -1;
    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        LayoutInflater inflater = LayoutInflater.from(context);
        View view;
        RecyclerView.ViewHolder holder;
        switch (viewType) {
            case VIEW_TYPE_DESIGN_TYPES:
                view = inflater.inflate(R.layout.item_home_design_types, parent, false);
                holder = new DesignTypesViewHolder(view);
                break;
            case VIEW_TYPE_DESIGNS:
                view = inflater.inflate(R.layout.item_home_designs, parent, false);
                holder = new DesignsViewHolder(view);
                break;
            default:
                view = inflater.inflate(R.layout.item_home_designs, parent, false);
                holder = new DesignsViewHolder(view);
                break;
        }
        return holder;
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
        if (holder.getItemViewType() == VIEW_TYPE_DESIGN_TYPES)
            designTypesView((DesignTypesViewHolder) holder);
        else if (holder.getItemViewType() == VIEW_TYPE_DESIGNS)
            designsView((DesignsViewHolder) holder);
    }


    private void designTypesView(DesignTypesViewHolder holder) {
        HomeAdapterDesignTypes homeAdapterDesignTypes = new HomeAdapterDesignTypes(getDesignTypes());
        holder.recyclerView.setAdapter(homeAdapterDesignTypes);
    }

    private void designsView(DesignsViewHolder holder) {
        HomeAdapterDesigns homeAdapterDesigns = new HomeAdapterDesigns(getDesigns());
        holder.recyclerView.setAdapter(homeAdapterDesigns);
    }

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

    public void updateFeeds(ArrayList<Object> mFeeds) {
        feeds.addAll(mFeeds);
        notifyDataSetChanged();
    }

    public class DesignTypesViewHolder extends RecyclerView.ViewHolder {
        RecyclerView recyclerView;
        DesignTypesViewHolder(View itemView) {
            super(itemView);
            recyclerView = itemView.findViewById(R.id.rvHomeDesignTypes);
            recyclerView.setLayoutManager(new LinearLayoutManager(context, LinearLayoutManager.HORIZONTAL, false));
            ItemOffsetDecoration itemDecoration = new ItemOffsetDecoration(context, R.dimen.item_offset);
            recyclerView.addItemDecoration(itemDecoration);
        }
    }

    public class DesignsViewHolder extends RecyclerView.ViewHolder {
        RecyclerView recyclerView;
        DesignsViewHolder(View itemView) {
            super(itemView);
            recyclerView = itemView.findViewById(R.id.rvHomeDesigns);
            recyclerView.setLayoutManager(new GridLayoutManager(context, 2));
            int spanCount = 2;
            int spacing = 15;
            boolean includeEdge = true;
            recyclerView.addItemDecoration(new GridSpacingItemDecoration(spanCount, spacing, includeEdge));
        }
    }

    private ArrayList<DesignType> getDesignTypes() {
        ArrayList<DesignType> singleHorizontals = new ArrayList<>();
        for(int i = 0 ; i < feeds.size(); i++) {
            Object object = feeds.get(i);
            if(object instanceof DesignType) {
                singleHorizontals.add((DesignType) object);
            }
        }
        return singleHorizontals;
    }

    private ArrayList<Design> getDesigns() {
        ArrayList<Design> singleVerticals = new ArrayList<>();
        for(int i = 0 ; i < feeds.size(); i++) {
            Object object = feeds.get(i);
            if(object instanceof Design) {
                singleVerticals.add((Design) object);
            }
        }
        return singleVerticals;
    }
}

现在，我的Horizontal Recyclerview位于位置0，并且具有静态数据项。 Vertical RecyclerView是动态的，我想为其实现无限滚动。我不知道如何同时管理和更新数据模型（POJO类）。因为两个Recyclerview的对象类型都不同。我应该为两者创建一个通用的POJO类吗？

我面临的另一个问题是，当列表末尾滚动时会有一个混蛋。

Answer 1

看起来您的父回收站视图仅包含两项：

@Override
public int getItemViewType(int position) {
    if (position == 0)
        return VIEW_TYPE_DESIGN_TYPES;
    if (position == 1)
        return VIEW_TYPE_DESIGNS;
    return -1;
}

但是从这里我可以看到，如果您有两个以上的项目-您最终将所有后续的所有者都创建为DesignsViewHolder：

default:
            view = inflater.inflate(R.layout.item_home_designs, parent, false);
            holder = new DesignsViewHolder(view);
            break;

如果打算-在网格项目中具有水平滚动的顶层回收者视图和下一个回收者视图，那么在一个布局中仅包含两个回收者视图是可以的。

<ConstraintLayout or ScrollView> - as u wish
  <RecyclerView\> - horizontal one
  <RecyclerView\> - vertical one, or with grid layout manager
<\ConstraintLayout or ScrollView>

编辑：在您的问题link的附件中，反之亦然。垂直滚动，最后一项水平滚动。在这种情况下，您可以切换回收者视图的顺序。

如果您想在回收站中使用真正不同的物品，请考虑使用Adapter Delegates模式。

注意：在回收者视图中有很多不同的滚动方向并不容易维护。有时会出现diff错误，这些错误很难修复。在某些情况下，更容易以 在回收站视图中具有滚动视图 ， 而不是 回收站视图内的回收站视图 。 RecyclerView的内部结构非常复杂，可以优化性能和项目可重复使用性。在大多数情况下，将这种布局与垂直滚动混合起来，您需要5-10个水平滚动的简单对象。这里有很多要讨论的内容，具体取决于大小写。

看看Joe's problem和一个不错的GitHub lib，它们应该有助于Adapters Delegate模式的理解。祝你好运！

Android Hetrogenenous recyclerview混蛋和数据模型混乱

1 个答案: