android - 如何在 Android 上实现 Material Design 展开/折叠列表？

Question

我正在寻找实现这种风格的 Material list 。我怎样才能在安卓上做到这一点？我应该看什么课？是否有任何现有的库可以使实现这一点变得容易？

Answer 1

是的，您可以使用库 SectionedRecyclerViewAdapter 轻松实现它.有一个完整的工作示例 here .

基本上你创建一个section类:

class MySection extends StatelessSection {

    String title;
    List<String> list;
    boolean expanded = true; // true if you want it to be displayed expanded initially

    public MySection(String title, 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.title = title;
        this.list = list;
    }

    @Override
    public int getContentItemsTotal() {
        return expanded? list.size() : 0;
    }

    @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(title);

        // handles the click on the header to toggle the expanded variable
        headerHolder.rootView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                expanded = !expanded;
                headerHolder.imgArrow.setImageResource(
                        expanded ? R.drawable.ic_keyboard_arrow_up_black_18dp : R.drawable.ic_keyboard_arrow_down_black_18dp
                );
                sectionAdapter.notifyDataSetChanged();
            }
        });
    }
}

然后你用你的部分设置 RecyclerView:

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

// Create your sections with the list of data for each topic
MySection topic1Section = new MySection("Attractions", attractionsList);
MySection topic2Section = new MySection("Dining", diningList);

// Add your Sections to the adapter
sectionAdapter.addSection(topic1Section);
sectionAdapter.addSection(topic2Section);

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