Erweiterbarer Recycler Anzeigen nur eines Elements im übergeordneten Element

Question

Meine Recycler-Ansicht hat einen übergeordneten und einen untergeordneten Datensatz. Mein Elternteil zeigt nur einen Gegenstand mit allen Themen in diesem einen Gegenstand an. Ich kann meinen Code unten posten. Ich bin nicht sicher, was ich tun muss, um dies zu korrigieren, da dies das erste Mal ist, dass ich Expandable Views verwende. Ich habe die ganze Klasse unten gepostet. Nicht sicher, was Sie sehen mussten.

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); 
    } 

} 

Fehle ich gerade etwas wirklich einfaches? Weil das sich wirklich kompliziert anfühlt lol

Vielen Dank im Voraus!

Answer 1

Ich bin mir nicht sicher, ob Ihr Code gut genug ist.
Siehe https://github.com/anandbose/ExpandableListViewDemo ist ziemlich klar

Answer 2

Sie können es einfach mit der Bibliothek SectionedRecyclerViewAdapter implementieren. Es gibt ein vollständiges Arbeitsbeispiel here.

Grundsätzlich erstellen Sie einen Abschnitt Klasse:

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(); 
      } 
     }); 
    } 
} 

Dann stellen Sie die RecyclerView mit Abschnitten auf:

// 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);