【问题标题】:RecyclerView not populating inside fragment using volleyRecyclerView 没有使用 volley 填充片段内部
【发布时间】:2017-02-24 03:18:36
【问题描述】:

我的 recyclerview 没有填充到片段中。我从凌空得到了适当的回应。我已经以正确的格式解析了 arraylist 中的 JSON,唯一的问题是 recyclerview 没有填充

MyFragment.java

@Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View view = inflater.inflate(R.layout.fragment_undekha_tadka, container, false);
        recyclerView = (RecyclerView) view.findViewById(R.id.recyclerView);
        myVolleyOperation(view);
        return view;
    }

    private void myVolleyOperation(View v) {
        volleySingleton = VolleySingleton.getInstance();
        requestQueue = volleySingleton.getRequestQueue();
        String url = "http://abcd.com/undekha.html";

        StringRequest stringRequest = new StringRequest(Request.Method.GET, url, new Response.Listener<String>() {
            @Override
            public void onResponse(String response) {
                jsonParsing(response);
                Toast.makeText(getContext(), response, Toast.LENGTH_SHORT).show();
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                Toast.makeText(getContext(), "ERROR\n" + error.toString(), Toast.LENGTH_SHORT).show();
            }
        });

        requestQueue.add(stringRequest);

        recyclerViewAdapter = new RecyclerViewAdapter(undekhaList, v.getContext());
        layoutManager = new LinearLayoutManager(getContext());
        recyclerView.setLayoutManager(layoutManager);
        recyclerView.setAdapter(recyclerViewAdapter);
    }

RecyclerViewAdapter.java

public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.RecyclerViewHolder> {
    ArrayList<UndekhaModel> myArrayList = new ArrayList<>();
    Context context;

    VolleySingleton volleySingleton;
    ImageLoader imageLoader;

    public RecyclerViewAdapter(ArrayList<UndekhaModel> myArrayList, Context context) {
        this.myArrayList = myArrayList;
        this.context = context;

        volleySingleton = VolleySingleton.getInstance();
        imageLoader = volleySingleton.getImageLoader();
    }

    @Override
    public RecyclerViewAdapter.RecyclerViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.single_row, parent, false);
        RecyclerViewHolder recyclerViewHolder = new RecyclerViewHolder(view, context, myArrayList);

        return recyclerViewHolder;
    }

    @Override
    public void onBindViewHolder(final RecyclerViewAdapter.RecyclerViewHolder holder, int position) {
        UndekhaModel undekhaModel = myArrayList.get(position);

        holder.title.setText(undekhaModel.getTitle());

        String loadUrl = "http://img.youtube.com/vi/" + undekhaModel.getId() + "/0.jpg";
        if (loadUrl!=null){
            imageLoader.get(loadUrl, new ImageLoader.ImageListener() {
                @Override
                public void onResponse(ImageLoader.ImageContainer response, boolean isImmediate) {
                    holder.thumbnail.setImageBitmap(response.getBitmap());
                }

                @Override
                public void onErrorResponse(VolleyError error) {
                    holder.thumbnail.setImageResource(R.mipmap.ic_launcher);
                }
            });
        }
    }

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

    public static class RecyclerViewHolder extends RecyclerView.ViewHolder {

        TextView title;
        ImageView thumbnail;
        ArrayList<UndekhaModel> modelArrayList = new ArrayList<>();
        Context context;

        public RecyclerViewHolder(View itemView, final Context ctx, final ArrayList<UndekhaModel> modelArrayList) {
            super(itemView);
            this.context = ctx;
            this.modelArrayList = modelArrayList;

            title = (TextView) itemView.findViewById(R.id.tvTitle);
            thumbnail = (ImageView) itemView.findViewById(R.id.ivShow);
        }
    }
}

【问题讨论】:

    标签: android android-recyclerview android-volley


    【解决方案1】:

    您的方法jsonParsing() 需要为您的RecyclerViewAdapter 填充数据,需要通知更新,并且适配器需要返回它正在管理的项目的正确计数。现在它的 getItemCount() 总是返回 0,所以 RecyclerView 不认为有什么可显示的。

    【讨论】:

    • 您需要提供更多代码(如jsonParsing() 例程)以及适配器中数据的更新方式。
    • jsonParsing() 工作正常。查了一下,觉得发jsonParsing()代码也没用
    • 它可能很好地解析了 json,但它实际上对数据做了什么?这就是发布代码的原因。现在,您的适配器永远不会更新数据。
    【解决方案2】:

    与这里相同的问题

    https://stackoverflow.com/a/35802948/2144418

    尝试在布局管理器之前设置适配器

    myVolleyOperation 上的最后两行更改为此

    recyclerView.setAdapter(recyclerViewAdapter);
    recyclerView.setLayoutManager(layoutManager);
    

    【讨论】:

    • 你可以尝试在适配器的 getItemCount 上放置一个断点,看看它返回了什么?
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