Expandable Recycler僅查看父母中的一個項目

Question

我的回收者視圖有父母和子女。我的父母只顯示一個項目，然後在該項目中顯示所有主題。我可以在下面發佈我的代碼我不確定我需要做什麼來糾正此問題，因爲這是我第一次使用可擴展視圖。我已經在下面發佈了全班。不知道你需要看到什麼。

public class TopicFragment extends Fragment { 

    private View mRootView; 
    private CategoryResponse mData; 
    private CategoryFeedDataFactory mDataFactory; 
    private List<String> mCategories; 

    //Expandable Recycler View 
    private List<TopicItem> mTopics; 
    private TopicResponse mTopic; 
    private TopicFeedDataFactory mTopicDataFactory; 
    private CategoryItem mCategoryItem; 


    //RecyclerView 
    private RecyclerView mRecyclerView; 
    private LinearLayoutManager mLayoutManager; 
    private TopicExpandableAdapter mExpandableAdapter; 


    public TopicFragment() { 
     // Required empty public constructor 
    } 


    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
         Bundle savedInstanceState) { 

     mRootView = inflater.inflate(R.layout.fragment_topic, container, false); 

     initUI(); 

     return mRootView; 

    } 

    private void initUI() { 

     mRecyclerView = (RecyclerView) mRootView.findViewById(R.id.categoryView); 
     mLayoutManager = new LinearLayoutManager(getActivity().getApplication().getApplicationContext()); 

     loadData(); 


    } 

    private void loadData() { 
     mDataFactory = new CategoryFeedDataFactory(getActivity().getApplicationContext()); 
     mTopicDataFactory = new TopicFeedDataFactory(getActivity().getApplicationContext()); 

     mDataFactory.getCategoryFeed(new CategoryFeedDataFactory.CategoryFeedDataFactoryCallback() { 
      @Override 
      public void onCategoryDataReceived(CategoryResponse response) { 

       mData = response; 

      } 

      @Override 
      public void onCategoryDataFailed(Exception exception) { 

      } 
     }); 

     mTopicDataFactory.getAllTopics(new TopicFeedDataFactory.TopicFeedDataFactoryCallback() { 
      @Override 
      public void onTopicDataReceived(TopicResponse response) { 

       mTopic = response; 
       populateUIWithData(); 

      } 

      @Override 
      public void onTopicDataFailed(Exception exception) { 

      } 
     }); 
    } 

    private void populateUIWithData() { 
     mCategories = new ArrayList<>(); 
     mTopics = new ArrayList<>(); 

     for (int i = 0; i <= mData.getItems().size(); i++) { 
      if (mData != null) { 
       if (mData.getItem(i) != null) { 
        if (mData.getItem(i).getCategoryItem() != null && 
          mData.getItem(i).getCategoryItem().getName() != null) { 
         mCategories.add(mData.getItem(i).getCategoryItem().getName()); 
        } 
       } 

      } 

      for (int j = 0; j <= mTopic.getItems().size(); j++) { 
       if (mTopic != null) 
        if (mTopic.getItem(j) != null) 
         if (mTopic.getItem(j).getTopicItem() != null) 
          if (mTopic.getItem(j).getTopicItem().getCategoryID() != null) { 
           if (mData.getItem(i) != null && mData.getItem(i).getCategoryItem() != null) 
            if (mData.getItem(i).getCategoryItem().getId() != null) 
            if (mTopic.getItem(j).getTopicItem().getCategoryID().equals 
              (mData.getItem(i).getCategoryItem().getId())) { 

             mTopics.add(mTopic.getItem(j).getTopicItem()); 
             mCategoryItem = 
               new CategoryItem(mData.getItem(i).getCategoryItem().getName(), 
                 mTopics); 

            } 

         } 
     } 
    } 


    final List<CategoryItem> categoryItems = Collections.singletonList(mCategoryItem); 

     mExpandableAdapter = new TopicExpandableAdapter(getActivity(), categoryItems); 
     mExpandableAdapter.setExpandCollapseListener(new ExpandableRecyclerAdapter.ExpandCollapseListener() { 
      @Override 
      public void onListItemExpanded(int position) { 
       CategoryItem expandedCategoryItem = categoryItems.get(position); 

       String toastMsg = getResources().getString(R.string.expanded, expandedCategoryItem); 
       Toast.makeText(getActivity().getApplicationContext(), 
         toastMsg, 
         Toast.LENGTH_SHORT) 
         .show(); 

      } 

      @Override 
      public void onListItemCollapsed(int position) { 
       CategoryItem collapsedCategoryItem = categoryItems.get(position); 

       String toastMsg = getResources().getString(R.string.collapsed, collapsedCategoryItem.getName()); 
       Toast.makeText(getActivity().getApplicationContext(), 
         toastMsg, 
         Toast.LENGTH_SHORT) 
         .show(); 

      } 
     }); 
     mRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity())); 
     mRecyclerView.setAdapter(mExpandableAdapter); 
    } 

} 

我是否錯過了一些非常簡單的東西？因爲這感覺真的很複雜大聲笑

在此先感謝！

Answer 1

我不確定你的代碼是否足夠好。
請參閱https://github.com/anandbose/ExpandableListViewDemo很清楚

Answer 2

您可以使用庫SectionedRecyclerViewAdapter輕鬆實現它。有一個完整的工作示例here。

基本上你創建一個部分類：

class MySection extends StatelessSection { 

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

    public MySection(String title, List<TopicItem> 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).getTopicName()); 
    } 

    @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(); 
      } 
     }); 
    } 
} 

然後你建立你的部分的RecyclerView：

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

// Create your sections with the list of data for each category 
MySection cat1Section = new MySection(mCategories.get(0), cat1TopicItemList); 
MySection cat2Section = new MySection(mCategories.get(1), cat2TopicItemList); 

// Add your Sections to the adapter 
sectionAdapter.addSection(cat1Section); 
sectionAdapter.addSection(cat2Section); 

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