Question

在我的应用程序中，我有一个从json文件填充的图像的回收视图。在我的工具栏菜单中，我添加了一个选项，根据该选择过滤图像。我的json中的每个项目都标有一个选择类别（包括示例）。我试图找出如何根据用户选择过滤此Recyclerview列表。我搜索和搜索，但似乎无法找到解决方案。如果有人可以帮助解决sudocode或一个例子，我会非常感激。以下是我的课程。

json示例：

{ "image_url": "http://www.nm-studios.com/trek_lines.png",
      "title":"Trek1",
      "package_url":"http://www.nm-studios.com/trek_lines.png",
      "id":lines},
{ "image_url": "http://www.nm-studios.com/stuffs/trek_lines2.png",
      "title":"Trek2",
      "premium":"PRO ONLY",
      "package_url":"http://www.nm-studios.com/trek_lines2.png",
      "id":lines},
{ "image_url": "http://www.nm-studios.com/wall_start.png",
      "title":"GreyShadowed",
      "premium":"PRO ONLY",
      "package_url":"http://www.nm-studios.com/wall_start.png",
      "id":lines},

用于显示列表的片段：

    public class WallpapersFragment extends Fragment {
    private static final String TAG = "RecyclerViewExample";
    private List<FeedWallpapers> feedItemList = new ArrayList<FeedWallpapers>();
//added static might remove
    private static RecyclerView mRecyclerView;
    private static MyRecyclerAdapterWallpapers adapter;
    public String filter_list;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { 
    View view = inflater.inflate( R.layout.fragment_wall_recycler, container, false);
        setHasOptionsMenu(true);
        /* Allow activity to show indeterminate progress-bar */
        //getActivity().requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);

        /* Initialize recycler view */
        mRecyclerView = (RecyclerView) view.findViewById(R.id.my_wall_recycler);
        mRecyclerView.setHasFixedSize(true);
        //mRecyclerView.setLayoutManager(new GridLayoutManager(getActivity(),2));
        mRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));

        /*Downloading data from below url*/
        final String url = "http://www.nm-studios.com/Json/wallpaper_list.json";
        new AsyncHttpTask().execute(url);
        return view;
    }

    public class AsyncHttpTask extends AsyncTask<String, Void, Integer> {

     /*   @Override
        protected void onPreExecute() {
            setProgressBarIndeterminateVisibility(true);
        }*/

        @Override
        protected Integer doInBackground(String... params) {
            InputStream inputStream = null;
            Integer result = 0;
            HttpURLConnection urlConnection = null;

            try {
                /* forming th java.net.URL object */
                URL url = new URL(params[0]);
                urlConnection = (HttpURLConnection) url.openConnection();

                /* for Get request */
                urlConnection.setRequestMethod("GET");
                int statusCode = urlConnection.getResponseCode();

                /* 200 represents HTTP OK */
                if (statusCode ==  200) {
                    BufferedReader r = new BufferedReader(new InputStreamReader(urlConnection.getInputStream()));
                    StringBuilder response = new StringBuilder();
                    String line;
                    while ((line = r.readLine()) != null) {
                        response.append(line);
                    }

                    parseResult(response.toString());
                    result = 1; // Successful
                }else{
                    result = 0; //"Failed to fetch data!";
                }

            } catch (Exception e) {
                Log.d(TAG, e.getLocalizedMessage());
            }
            return result; //"Failed to fetch data!";
        }

        @Override
        protected void onPostExecute(Integer result) {
           // setProgressBarIndeterminateVisibility(false);
            /* Download complete. Lets update UI */
            if (result == 1) {
                adapter = new MyRecyclerAdapterWallpapers(getActivity(), feedItemList);
                mRecyclerView.setAdapter(adapter);
            } else {
                Log.e(TAG, "Failed to fetch data!");
            }
        }

    }

    private void parseResult(String result) {
        try {
            JSONObject response = new JSONObject(result);
            JSONArray products = response.optJSONArray("products");

            /*Initialize array if null*/
            if (null == feedItemList) {
                feedItemList = new ArrayList<FeedWallpapers>();
            }

            for (int i = 0; i < products.length(); i++) {
                JSONObject product = products.optJSONObject(i);

                FeedWallpapers item = new FeedWallpapers();
                item.setTitle(product.optString("title"));
                item.setImage_url(product.optString("image_url"));
                item.setPackage_url(product.optString("package_url"));
                item.setPremium_wall(product.optString("premium"));
                item.setIds(product.optString("ids"));
                feedItemList.add(item);
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }
    }
    @Override
    public void onCreateOptionsMenu(
            Menu menu, MenuInflater inflater) {
        inflater.inflate(R.menu.wall_menu, menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

        switch (item.getItemId()) {
            case R.id.all:
                if (item.isChecked()) item.setChecked(false);
                else item.setChecked(true);
                filter_list = "";
                return true;
            case R.id.text:
                if (item.isChecked()) item.setChecked(false);
                else item.setChecked(true);
                filter_list = "android_text";
                return true;
            case R.id.lines:
                if (item.isChecked()) item.setChecked(false);
                else item.setChecked(true);
                filter_list = "lines";
                return true;
            case R.id.windows:
                if (item.isChecked()) item.setChecked(false);
                else item.setChecked(true);
                filter_list = "windows";
                return true;
            case R.id.material:
                if (item.isChecked()) item.setChecked(false);
                else item.setChecked(true);
                filter_list = "material";
                return true;
            case R.id.rivalry:
                if (item.isChecked()) item.setChecked(false);
                else item.setChecked(true);
                filter_list = "rivalry";
                return true;
            default:
                return super.onOptionsItemSelected(item);
        }
    }
}

我的持有人：

public class FeedWallpapersHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
    public ImageView thumbnail;
    public TextView titles;
    public Context context;
    public TextView wall_url;
    public int wallPosition;
    public TextView premiumTag;

    public FeedWallpapersHolder(View view) {
        super(view);
    view.setOnClickListener(this);
        this.thumbnail = (ImageView) view.findViewById(R.id.wall_image);
        this.titles = (TextView) view.findViewById(R.id.wall_title);
        this.wall_url = (TextView) view.findViewById(R.id.wall_download_url);
        this.premiumTag = (TextView) view.findViewById(R.id.premium_tag_walls);

    context = view.getContext();

    }
    @Override
    public void onClick(View view) {
        wallPosition = getPosition();
        //Toast.makeText(view.getContext(), "I'm clicked!! " + wallPosition, Toast.LENGTH_SHORT).show();
        //doing some stuff here maybe
        final Intent wall_intent = new Intent(view.getContext(), FullScreenActivity.class);
        final String WallUrl = ((TextView) view.findViewById(R.id.wall_download_url)).getText().toString();
        final String Premium = ((TextView) view.findViewById(R.id.premium_tag_walls)).getText().toString();
        final String fn_wall = ((TextView) view.findViewById(R.id.wall_title)).getText().toString() +".png";
        wall_intent.putExtra("FullImageUrl", WallUrl);
        wall_intent.putExtra("FnWallFinal", fn_wall);
        Log.i("premium Check", Premium);
        //this starts my premium check

            Log.i("launch download dialog", "launching");
            Log.i("url", WallUrl);
            context.startActivity(wall_intent);

    }


}

我的适配器：

public class MyRecyclerAdapterWallpapers extends RecyclerView.Adapter<FeedWallpapersHolder> {

    private List<FeedWallpapers> feedItemList;
    private Context mContext;


    public MyRecyclerAdapterWallpapers(Context context, List<FeedWallpapers> feedItemList) {
        this.feedItemList = feedItemList;
        this.mContext = context;

    }

    @Override
    public FeedWallpapersHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
        View v = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.wall_card_layout, null);
        FeedWallpapersHolder mh = new FeedWallpapersHolder(v);
        return mh;
    }

    @Override
    public void onBindViewHolder(FeedWallpapersHolder feedListRowHolder, int i) {
        FeedWallpapers feedItem = feedItemList.get(i);
        int n = feedListRowHolder.thumbnail.getWidth();
        Point Size = new Point();
        WindowManager wm = (WindowManager) mContext.getSystemService(Context.WINDOW_SERVICE);
        Display display = wm.getDefaultDisplay();
        display.getSize(Size);
        int scrWidth = Size.x;
        String nstring = Integer.toString(n);
        String nwidth = Integer.toString(scrWidth);
        Log.i("width", nwidth);
        Picasso.with(mContext).load(feedItem.getImage_url())

                .error(R.drawable.placeholder)
                //.placeholder(R.drawable.placeholder)
                .transform(new FitTransformations(scrWidth,false))
                //.fit().centerCrop()
                .into(feedListRowHolder.thumbnail);
        Log.i("the string", feedItem.getImage_url());

        feedListRowHolder.titles.setText(Html.fromHtml(feedItem.getTitle()));
        feedListRowHolder.premiumTag.setText(Html.fromHtml(feedItem.getPremium_wall()));
        feedListRowHolder.wall_url.setText((Html.fromHtml(feedItem.getPackage_url())));
    }

    @Override
    public int getItemCount() {
        return (null != feedItemList ? feedItemList.size() : 0);
    }
}

Answer 1

没有足够的时间来分析您的代码，所以我不确定您已经完成了什么，这就是我要做的。首先从那些json对象中创建对象并将它们放在List中。

创建一个方法，获取这些对象的列表，并按照您想要的方式对它们进行排序（或删除您不想要的项目）。

private List<Object> filterMyList(List<Object> list, String category) {
    //...
    for (Object obj : list) {
        // if (!obj.getCategory().equals(category)) -> remove from list.
    }
    //...
    return editedList;
}

在适配器中创建一个类似

的方法

public void updateRecyclerData(List<Object> feedItemList) {
      this.feedItemList = feedItemList;
      notifyDatasetChanged(); //This will update recyclerview
}

最终产品应如下所示：

adapter.updateRecyclerData(filterMyList(myList, "material"));

显然你想让这些类别成为常量。

从菜单项选择中筛选回收站视图

1 个答案: