android - 具有不同项目（组和子项目）的 RecyclerView

Question

我正在做一个RecyclerView有两个不同项目的项目，但我不知道我该怎么做。

首先：我有ArrayList一个对象，但我不知道如何将与日期相关的时间放在RecyclerView.

• 日期 - 组项目。

• 时间 - 子项。

   Object {
   Date date;
   ArrayList times;
   }
  

第二：当项目的位置不是预期时，如何根据适配器中的项目更改 spanSize？( GridLayoutManager)

Answer 1

要回答您的第二部分，要根据项目类型（组或子项）更改跨度大小，请在GridLayoutManager. 在您的适配器中，您getItemViewType()根据位置实现并返回视图类型。例如，0 表示组，1 表示孩子，在这种情况下MyAdapter.VIEW_TYPE_GROUP为 0。

RecyclerView list = (RecyclerView) view.findViewById(
        R.id.my_fragment_my_recycler_view);
GridLayoutManager layoutManager = new GridLayoutManager(getActivity(), 5);
layoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
    @Override
    public int getSpanSize(int position) {
        if (list.getAdapter().getItemViewType(position) == MyAdapter.VIEW_TYPE_GROUP) {
            // return the number of columns so the group header takes a whole row
            return 5
        }
        // normal child item takes up 1 cell
        return 1;
    }
});

Answer 2

您可以使用库SectionedRecyclerViewAdapter将您的项目分组并为每个部分添加标题：

class MySection extends StatelessSection {

    String date;
    List<String> list;

    public MySection(String date, List<String> list) {
        // call constructor with layout resources for this Section header, footer and items 
        super(R.layout.section_header, R.layout.section_item);

        this.date = date;
        this.list = list;
    }

    @Override
    public int getContentItemsTotal() {
        return list.size(); // number of items of this section
    }

    @Override
    public RecyclerView.ViewHolder getItemViewHolder(View view) {
        // return a custom instance of ViewHolder for the items of this section
        return new MyItemViewHolder(view);
    }

    @Override
    public void onBindItemViewHolder(RecyclerView.ViewHolder holder, int position) {
        MyItemViewHolder itemHolder = (MyItemViewHolder) holder;

        // bind your view here
        itemHolder.tvItem.setText(list.get(position));
    }

    @Override
    public RecyclerView.ViewHolder getHeaderViewHolder(View view) {
        return new SimpleHeaderViewHolder(view);
    }

    @Override
    public void onBindHeaderViewHolder(RecyclerView.ViewHolder holder) {
        MyHeaderViewHolder headerHolder = (MyHeaderViewHolder) holder;

        // bind your header view here
        headerHolder.tvItem.setText(date);
    }
}

然后你用你的部分设置 RecyclerView 并使用 GridLayoutManager 更改标题的 spanSize：

// Create an instance of SectionedRecyclerViewAdapter 
SectionedRecyclerViewAdapter sectionAdapter = new SectionedRecyclerViewAdapter();

// Create your sections with the list of data
MySection date1Section = new MySection("Date 1", date1List);
MySection date2Section = new MySection("Date 2", date2List);

// Add your Sections to the adapter
sectionAdapter.addSection(date1Section);
sectionAdapter.addSection(date2Section);

// set up a gridlayoutmanager to change the spansize of the header
GridLayoutManager glm = new GridLayoutManager(getContext(), 2);
glm.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
    @Override
    public int getSpanSize(int position) {
        switch(sectionAdapter.getSectionItemViewType(position)) {
            case SectionedRecyclerViewAdapter.VIEW_TYPE_HEADER:
                return 2;
            default:
                return 1;
        }
    }
});

// Set up your RecyclerView with the SectionedRecyclerViewAdapter
RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recyclerview);
recyclerView.setLayoutManager(glm);
recyclerView.setAdapter(sectionAdapter);