Question

我正在创建RecyclerView并从JSON获取数据，我的应用会检查项目区域是否与前一个区域不同，然后它会显示带有区域名称的标题，否则它将继续创造物品，我希望很清楚，我无法理解如何使用getItemViewType()功能查看我的Adapter

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


    final int TYPE_HEADER = 0;
    final int TYPE_ITEM = 1;
    private ArrayList<Salon> mListItems = new ArrayList<>();
    private ImageLoader mImageLoader;
    TextView textViewItemSection;
    public AdapterItems(Context context) {


        mImageLoader = AppController.getInstance().getImageLoader();

    }

    public void setmListItems(ArrayList<Salon> mListItems) {
        this.mListItems = mListItems;
        //update the adapter to reflect the new set of mListItems
        notifyDataSetChanged();
    }


    @Override
    public int getItemViewType(int position) {

        if (position == 0)
            return TYPE_HEADER;
        return TYPE_ITEM;
    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

        if (viewType == TYPE_ITEM) {
            View itemView = LayoutInflater.
                    from(parent.getContext()).
                    inflate(R.layout.custom_row_item, parent, false);
            return new ItemHolder(itemView);
        } else {
            View itemView = LayoutInflater.
                    from(parent.getContext()).
                    inflate(R.layout.custom_row_header, parent, false);
            return new HeaderHolder(itemView);
        }


    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {

        //textViewItemSection.setVisibility(View.GONE);



       /* salon_id =  (TextView)itemView.findViewById(R.id.salon_id);
        salon_name = (TextView)itemView.findViewById(R.id.salon_name);
        salon_address = (TextView)itemView.findViewById(R.id.salon_address);

        salon_logo = (NetworkImageView)itemView.findViewById(R.id.salon_logo);
        salon_gender = (ImageView)itemView.findViewById(R.id.salon_gender);*/

        if (holder instanceof HeaderHolder) {



        } else {
            ItemHolder itemHolder = (ItemHolder) holder ;
            Salon currentItem = mListItems.get(position);
            //if (position == 0) {
              /*  textViewItemSection.setText("");
                textViewItemSection.setVisibility(View.VISIBLE);
                textViewItemSection.setText(currentItem.getRegion());*/
            itemHolder.salon_id.setText(currentItem.getSalon_id());
            itemHolder.salon_name.setText(currentItem.getA_name());
            itemHolder.salon_address.setText(currentItem.getA_address());
            itemHolder.salon_region.setText(currentItem.getRegion());


            String urlLogo = currentItem.getLogo();
            String urlGender = currentItem.getGender();
            loadImages(urlLogo, itemHolder);
        }

        // }

    }

    private void loadImages(String urlThumbnail, final ItemHolder holder) {

        mImageLoader.get(urlThumbnail, new ImageLoader.ImageListener() {
            @Override
            public void onResponse(ImageLoader.ImageContainer response, boolean isImmediate) {
                holder.salon_logo.setImageBitmap(response.getBitmap());
                //holder.salon_gender.setImageBitmap(response.getBitmap());

            }

            @Override
            public void onErrorResponse(VolleyError error) {

            }
        });
    }


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

    private class HeaderHolder extends RecyclerView.ViewHolder {


        public HeaderHolder(View itemView) {
            super(itemView);


            textViewItemSection = (TextView) itemView.findViewById(R.id.textViewItemSection);


        }
    }


    private class ItemHolder extends RecyclerView.ViewHolder {

        public TextView title;
        public ImageView salon_logo;
        public ImageView salon_gender;
        public TextView salon_id, salon_name, salon_address, salon_region;


        public ItemHolder(View itemView) {
            super(itemView);


            salon_id = (TextView) itemView.findViewById(R.id.salon_id);
            salon_name = (TextView) itemView.findViewById(R.id.salon_name);
            salon_address = (TextView) itemView.findViewById(R.id.salon_address);
            salon_region = (TextView) itemView.findViewById(R.id.salon_region);
            textViewItemSection = (TextView) itemView.findViewById(R.id.textViewItemSection);

            salon_logo = (ImageView) itemView.findViewById(R.id.salon_logo);
            salon_gender = (ImageView) itemView.findViewById(R.id.salon_gender);


        }
    }
}

这是我获取数据的地方

 JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(URL, new Response.Listener<JSONObject>() {
        @Override
        public void onResponse(JSONObject response) {
            hidePDialog();

            try {
                JSONArray regionArray = response.getJSONArray("SALON");
                for (int a = 0; a < regionArray.length(); a++) {
                    JSONObject region = regionArray.getJSONObject(a);
                    JSONArray jsonArray1 = region.getJSONArray("saloon_list");
                    for (int i = 0; i < jsonArray1.length(); i++) {


                        JSONObject salonDetails = jsonArray1.getJSONObject(i);
                        Salon salon = new Salon();


                        //fill salon information
                        salon.setSalon_id(salonDetails.getString("salon_id"));
                        salon.setRegion(region.getString("a_name").trim());
                        salon.setLogo(salonDetails.getString("logo"));
                        salon.setA_name(salonDetails.getString("a_name"));
                        salon.setA_address(salonDetails.getString("a_address"));

                        salonList.add(salon);
                    }
                }
            } catch (JSONException e) {
                Toast.makeText(getApplicationContext(), "JSONExceptoion", Toast.LENGTH_SHORT).show();
                hidePDialog();
                e.printStackTrace();
            }
            // notifying list adapter about data changes
            // so that it renders the list view with updated data
            //customListAdapter.notifyDataSetChanged();
            salonRecycleView.setAdapter(adapterItems);
            adapterItems.setmListItems(salonList);

        }

    }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            Toast.makeText(getApplicationContext(), "onErrorResponse", Toast.LENGTH_SHORT).show();
            hidePDialog();
        }
    });
    AppController.getInstance().addToRequestQueue(jsonObjectRequest);
}

Answer 1

在getItemViewType中，您必须比较前一个位置的项目是否来自与当前位置不同的区域：

@Override
public int getItemViewType(int position) {

    if (position == 0)
        return TYPE_HEADER;

    if (mListItems.get(position).getRegion().equalsIgnoreCase(
        mListItems.get(position-1).getRegion()) {
        return TYPE_HEADER;
    }
    else {
        return TYPE_ITEM;
    }
}

问题是你的对象是这样的：

  Region   |  Name    
----------------------
| Region 1 | Salon A |
----------------------
| Region 1 | Salon B |
----------------------
| Region 2 | Salon C |
----------------------
| Region 3 | Salon D |
----------------------
| Region 3 | Salon E |
----------------------

您的代码最终会在Recyclerview中显示如下项目：

------------
| Region 1 |
------------
| Salon B  |
------------
| Region 2 |
------------
| Region 3 |
------------
| Salon E  |
------------

解决此问题的一个简单方法是为适配器创建“Section”对象：

class Section {
    boolean isHeader;
    String headerText;
    Salon salon;
}

更改适配器以获得章节列表：

private ArrayList<Section> mListItems = new ArrayList<>();

但是应该以这种方式创建列表：

  isHeader | headerText | Salon    
-----------------------------------
| true     | Region 1   | null    |
-----------------------------------
| false    |            | Salon A |
-----------------------------------
| false    |            | Salon B |
-----------------------------------
| true     | Region 2   | null    |
-----------------------------------
| false    |            | Salon C |
-----------------------------------
| true     | Region 3   | null    |
-----------------------------------
| false    |            | Salon D |
-----------------------------------
| false    |            | Salon E |
-----------------------------------

将getItemViewType（）更改为：

@Override
public int getItemViewType(int position) {
    if (mListItems.get(position).isHeader) {
        return TYPE_HEADER;
    }
    else {
        return TYPE_ITEM;
    }
}

然后相应地更改你的onBindViewHolder（）。

如果您不想自己编码，可以使用库SectionedRecyclerViewAdapter。

您可以看到它如何处理getItemViewType（）here。

如何使用json数据创建分段RecyclerView

1 个答案: