在我的 CustomListAdapter 上实现 Filterable 接口后无法重新加载 ListView 内容

Posted 2023-04-19

【中文标题】在我的 CustomListAdapter 上实现 Filterable 接口后无法重新加载 ListView 内容

【英文标题】：Can not reload ListView Content after implementing Filterable interface on my CustomListAdapter

【发布时间】：2016-02-05 09:53:00

【问题描述】：

我有两个问题。

第一个问题是 :: 在我在 CustomListAdapter 中实现 Filterable 接口以启用对列表数据的搜索后，我意识到每次尝试重新加载列表视图时，它都会拒绝填充列表视图甚至认为我能够从我的服务器获取数据。 （我的 ListView 总是在设备方向更改时重新加载，我还添加了一个重新加载按钮来重新加载 listView onclick）

第二个问题去 :: 我的搜索 EditView 很好地填充了我的 listView onchange 但我意识到当我清空 EditView 时，ListView 中的先前数据不会恢复/来-回到之前的内容

下面是我的活动代码

public class MainActivity extends Activity 

   private ListView mList;
   private List<Movie> movieList = new ArrayList<Movie>();
   EditText inputSearch;
       private CustomListAdapter adapter;
   private ImageView  reload_img;


    protected void onCreate(Bundle savedInstanceState) 
           super.onCreate(savedInstanceState);
           requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
           setContentView(R.layout.activity_main);

       mList = (ListView) findViewById(R.id.list);
       inputSearch = (EditText) findViewById(R.id.inputSearch);
           reload_img = (ImageView) findViewById(R.id.reload_list);


           adapter = new CustomListAdapter(this, movieList);
           mList.setAdapter(adapter);

        //FETCH Movie-Data FROM SERVER TO LIST
         fetchMovie();

        //Reload image click
             reload_img.setOnClickListener(new View.OnClickListener() 
             public void onClick(View arg0) 

                    reload_list();
                    
            );

        //SEARCH TEXTCHANGE
        inputSearch.addTextChangedListener(new TextWatcher() 

             @Override
             public void onTextChanged(CharSequence cs, int arg1, int arg2, int arg3) 
                   // When user changed the Text
                  MainActivity.this.adapter.getFilter().filter(cs.toString());
                //FLAGS Cannot resolve method 'getFilter()' here
                

             @Override
             public void beforeTextChanged(CharSequence arg0, int arg1, int arg2,
                                      int arg3) 
                  // TODO Auto-generated method stub

             

             @Override
             public void afterTextChanged(Editable arg0) 
                 // TODO Auto-generated method stub
             
          );




    


    //RELOAD LISTVIEW METHOD
            private void reload_list()
            

                pDialog = new ProgressDialog(MainActivity.this);
                // Showing progress dialog before making http request
                pDialog.setMessage("Synchronising....");
                pDialog.show();
                pDialog.setCancelable(false);
                pDialog.setCanceledOnTouchOutside(false);


                flag_loading = true;
                offSet = 0;
                inputSearch.setText("");
                movieList.clear();

                fetchMovie();
                //adapter.notifyDataSetChanged();



            


    //LOAD DATA FROM SERVER TO LISTVIEW USING VOLLEY
    private void fetchMovie()
            

                // showing refresh animation before making http call
                //swipeRefreshLayout.setRefreshing(true);

                // appending offset to url
               String url = Config.URL_TOP_250_URL + offSet;
                //String url = Config.MOVIE_JSON_URL;
               //String url = Config.MOVIE_JSON_URL_SHORT;

               // Toast.makeText(MainActivity.this,
                 //       "::Json loaded:: ", Toast.LENGTH_SHORT).show();

                JsonArrayRequest movieReq = new JsonArrayRequest(url,
                        new Response.Listener<JSONArray>() 
                            @Override
                            public void onResponse(JSONArray response) 
                                // Log.d(TAG, response.toString());
                                hidePDialog();

                                if (response.length() > 0) 

                                    //Toast.makeText(MainActivity.this,
                                      //     "Json String : \n"+ response.toString(), Toast.LENGTH_LONG).show();

                                    // Parsing json
                                   /**/ for (int i = 0; i < response.length(); i++) 
                                        try 

                                            JSONObject obj = response.getJSONObject(i);

                                            int rank = obj.getInt("rank");

                                            Movie movie = new Movie();

                                            // movie.setRank(obj.getInt("rank"));

                                            movie.setTitle(obj.getString("title"));
                                            movie.setThumbnailUrl(obj.getString("image"));
                                            movie.setRating(((Number) obj.get("rating"))
                                                    .doubleValue());

                                            movie.setYear(obj.getInt("releaseYear"));

                                            // Genre is json array
                                            JSONArray genreArry = obj.getJSONArray("genre");
                                            ArrayList<String> genre = new ArrayList<String>();
                                            for (int j = 0; j < genreArry.length(); j++) 
                                                genre.add((String) genreArry.get(j));
                                            
                                            movie.setGenre(genre);

                                            // adding movie to movies array
                                            movieList.add(movie);

                                            // updating offset value to highest value
                                            if (rank >= offSet)
                                                offSet = rank;
                                            flag_loading = false;
                                         catch (JSONException e) 
                                            e.printStackTrace();

                                            Toast.makeText(MainActivity.this,
                                                    "Network connection error \n "+  e.getMessage(), Toast.LENGTH_LONG).show();
                                        

                                    
                                    /**/

                                    // notifying list adapter about data changes
                                    // so that it renders the list view with updated data
                                    adapter.notifyDataSetChanged();

                                
                                else 
                                    Toast.makeText(MainActivity.this,
                                            "End of movie-list" , Toast.LENGTH_LONG).show();

                                


                            




                        , new Response.ErrorListener() 
                    @Override
                    public void onErrorResponse(VolleyError error) 
                        VolleyLog.d(TAG, "Error :: " + error.getMessage());
                        hidePDialog();


                    

                );

                // Adding request to request queue
                MyApplication.getInstance().addToRequestQueue(movieReq);
            

这是我的 CustomListAdapter 中的代码

public class CustomListAdapter extends BaseAdapter 

         private Activity activity;
     private LayoutInflater inflater;
     private List<Movie> movieItems;
      private List<Movie> originalMovieList;
         private String[] bgColors;
     private List<String>originalData = null;
     private List<String>filteredData = null;
     private ItemFilter mFilter = new ItemFilter();
         ImageLoader imageLoader = MyApplication.getInstance().getImageLoader();


         public CustomListAdapter(Activity activity, List<Movie> movieItems) 
             this.activity = activity;
             this.movieItems = movieItems;
        this.originalMovieList = movieItems;
             bgColors = activity.getApplicationContext().getResources().getStringArray(R.array.movie_serial_bg);
         
         @Override
         public int getCount() 
                return movieItems.size();
         

         @Override
        public Object getItem(int location) 
             return movieItems.get(location);
         

            @Override
            public long getItemId(int position) 
               return position;
            

         @Override
         public View getView(int position, View convertView, ViewGroup parent) 

            if (inflater == null)
              inflater = (LayoutInflater) activity
                 .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
             if (convertView == null)
                convertView = inflater.inflate(R.layout.list_row_image, null);

             if (imageLoader == null)
              imageLoader = MyApplication.getInstance().getImageLoader();
            NetworkImageView thumbNail = (NetworkImageView) convertView.findViewById(R.id.thumbnail);

             TextView serial = (TextView) convertView.findViewById(R.id.serial);
            TextView title = (TextView) convertView.findViewById(R.id.title);
            TextView rating = (TextView) convertView.findViewById(R.id.rating);
            TextView genre = (TextView) convertView.findViewById(R.id.genre);
            TextView year = (TextView) convertView.findViewById(R.id.releaseYear);

            // getting movie data for the row
            Movie m = movieItems.get(position);

            // thumbnail image
            thumbNail.setImageUrl(m.getThumbnailUrl(), imageLoader);

            // title
            title.setText(m.getTitle());

            // rating
             rating.setText("Rating: " + String.valueOf(m.getRating()));

            // genre
            String genreStr = "";
            for (String str : m.getGenre()) 
              genreStr += str + ", ";
              
            genreStr = genreStr.length() > 0 ? genreStr.substring(0,
                 genreStr.length() - 2) : genreStr;
             genre.setText(genreStr);

            // release year
             year.setText(String.valueOf(m.getYear()));

             String color = bgColors[position % bgColors.length];
            serial.setBackgroundColor(Color.parseColor(color));




            return convertView;
     




            public Filter getFilter() 
                return mFilter;
            

            private class ItemFilter extends Filter 
                @Override
                protected FilterResults performFiltering(CharSequence constraint) 

                    String filterString = constraint.toString().toLowerCase();

                    FilterResults results = new FilterResults();

                    //final List<String> list = originalData;
                    final List<Movie> list = movieItems;

                    int count = list.size();
                   // final ArrayList<String> nlist = new ArrayList<String>(count);
                    final ArrayList<Movie> nlist = new ArrayList<Movie>(count);

                    String filterableString ;

                    for (int i = 0; i < count; i++) 
                        filterableString = list.get(i).getTitle();
                        if (filterableString.toLowerCase().contains(filterString)) 
                           // nlist.add(filterableString);
                            nlist.add(list.get(i));
                        
                    

                    results.values = nlist;
                    results.count = nlist.size();

                    return results;
                

                @SuppressWarnings("unchecked")
                @Override
                protected void publishResults(CharSequence constraint, FilterResults results) 
                    //filteredData = (ArrayList<String>) results.values;
                    movieItems = (ArrayList<Movie>) results.values;
                    notifyDataSetChanged();
                

            

如你所见，我确实花时间将整个代码放在一起，但在这个路口，我头晕目眩，我不知道为什么

方向更改，在我将 Filterable 引入我的 CustomListAdapter 之后，之前用于重新填充的 listView 数据突然停止填充类，还有

当我清除搜索EditView时，ListView中的内容没有返回

当我点击重新加载按钮时，列表中的内容不会重新加载，就像设备方向改变时一样。

我真的很感激能帮助我的提示，因为我现在很困。 Thanks in Advance

-Edited CustomListAdapter我所做的更改是

               @SuppressWarnings("unchecked")
                @Override
                protected void publishResults(CharSequence constraint, FilterResults results) 
                    //filteredData = (ArrayList<String>) results.values;
                    //movieItems = (ArrayList<Movie>) results.values;
                    movieItems.clear();
                    movieItems.addAll((ArrayList<Movie>) results.values);
                    notifyDataSetChanged();
                

            

也编辑了这个。已添加this.originalMovieList = new ArrayList<Movie>(movieItems);

public CustomListAdapter(Activity activity, List<Movie> movieItems) 
    this.activity = activity;
    this.movieItems = movieItems;
   // this.originalMovieList = movieItems;
    this.originalMovieList = new ArrayList<Movie>(movieItems);
    bgColors = activity.getApplicationContext().getResources().getStringArray(R.array.movie_serial_bg);

将此方法添加到 CustomListAdapter

//Add Below Method
public void reloadData()
    this.originalMovieList = new ArrayList<Movie>(movieItems);
    notifyDataSetChanged();

还将 MainActivity 类中的 notifyDataSetChanged() 替换为 this

                     `// notifying list adapter about data changes
                    // so that it renders the list view with updated data
                     //adapter.notifyDataSetChanged();
                      adapter.reloadData();`

-重新加载按钮现在可以正常工作，方向更改可以很好地重新加载页面，但搜索不会填充 ListView。 因此，搜索还不能正常工作

【问题讨论】：

尝试在适配器构造函数中将 this.originalMovieList = movieItems; 更改为 this.originalMovieList = new ArrayList(movieItems);。跨度>

@Dhaval-patel ::i 将 this.originalMovieList = movieItems; 更改为 this.originalMovieList = new ArrayList<Movie>(movieItems); 并且我也修改了以下行 final List<Movie> list = movieItems 现在更改为 final List<Movie> list = originalMovieList; 并更改了方法 movieItems = (ArrayList<Movie>) results.values; 上的 publicResults 代码也更改为 originalMovieList = (ArrayList<Movie>) results.values;

这使得重新加载工作但搜索搜索自动停止工作

final List list = originalMovieList; 更改是正确的。但不是 movieItems = (ArrayList) results.values 尝试 movieItems clear(); movieItems .addAll((ArrayList) results.values); 在 publishResults 方法中。

在方向更改时 lisView 会重新填充，但是当我单击按钮时，它会在加载后拒绝填充列表。 搜索也不起作用

【参考方案1】：

以下是您的问题的答案： 1。 ListView 没有重新加载？在函数中查看您的代码后：

@Override
protected void publishResults(CharSequence constraint, FilterResults results) 
         //filteredData = (ArrayList<String>) results.values;
         movieItems = (ArrayList<Movie>) results.values;
         notifyDataSetChanged();

当然，上述功能使您的适配器无法重新加载。为什么？因为这条线：movieItems = (ArrayList<Movie>) results.values;。您将适配器中的movieItems 引用到另一个List，因此movieList.add(movie); d 在您的MainActivity 中不再更改您的adapter 中的任何内容。如何克服它？修改如下：

movieItems.clear();
movieItems.addAll((ArrayList<Movie>) results.values);
notifyDataSetChanged();

但是，您的Search 功能仍然不起作用。为什么？因为在performFiltering 中，您尝试在movieItems 中搜索，而不是您的备份数据。 --> 你应该在你的备份数据中搜索：originalMovieList，然后通过添加movieItems来发布。

//change final List<Movie> list = movieItems;
//to belowed line in peformFiltering
final List<String> list = originalData;

为什么您的适配器没有恢复？因为你控制它，但你不恢复它。您应该在 peformFiltering 函数中恢复它：

protected FilterResults performFiltering(CharSequence constraint) 
      String filterString = constraint.toString().toLowerCase();
      if(TextUtils.isEmpty(filterString))
            // do restore backup data here
      else
           // do filter here.
      

【讨论】：

非常高兴得到您的帮助和时间。将适用于我的代码并更新您。虽然我之前已经调整了我的 publicResult 方法以拥有movieItems.clear(); movieItems.addAll((ArrayList<Movie>) results.values); notifyDataSetChanged();。在这个问题中也有更新。

我不知道你在if statement 中所说的// do restore backup data here 到底是什么意思，也不知道你在if statement 中所说的// do filter here. 是什么意思，因为我所尝试的只是在程序上进行标记。 -也许你应该填写if condition的在此处恢复备份数据方面，以便我可以了解你的意思

当你说我应该使用final List<String> list = originalData;时，我想相信你在这里犯了一个错误，因为程序中没有声明/实例化任何原始数据。 - 你是说final List<Movie> list = originalMovieList; 吗？

在这个链接上是我更新的代码..pastebin.com/RXGjrg4u它将帮助你了解我的代码现在与我所做的所有更改

@OkechukwuEze 是的，这是我的拼写错误。在do restore backup 中，您应该恢复原始数据，例如：` results.values = originalMovieList;结果.count = originalMovieList.size();`

【参考方案2】：

这就是我能够解决搜索代码的痛苦的方法。

在我的 MainActivity

上

public class MainActivity extends Activity 

 private List<Movie> currentMovieList = new ArrayList<Movie>();
 private List<Movie> originalMovieList = new ArrayList<Movie>();
 private CustomListAdapter adapter;
 private ListView mList;
 // Search EditText
 EditText inputSearch;

@Override
protected void onCreate(Bundle savedInstanceState) 
    super.onCreate(savedInstanceState);
    requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
    setContentView(R.layout.activity_main);

inputSearch = (EditText) findViewById(R.id.inputSearch);

adapter = new CustomListAdapter(this, currentMovieList);
    mList.setAdapter(adapter);


    inputSearch.addTextChangedListener(new TextWatcher() 

        public void onTextChanged(CharSequence cs, int arg1, int arg2, int arg3) 
            // When user changed the Text

            String filterString = cs.toString().toLowerCase();
            Log.e("TAG", "filterString:" + filterString);
            currentMovieList.clear();
            if (TextUtils.isEmpty(filterString)) 
                currentMovieList.addAll(originalMovieList);
            

            String filterableString;
            for (Movie movie : originalMovieList) 
                if (movie.getTitle().toLowerCase().contains(filterString)) 
                    currentMovieList.add(movie);
                
                else if (String.valueOf(movie.getYear()).toLowerCase().contains(filterString))
                
                    currentMovieList.add(movie);
                
                else if (String.valueOf(movie.getRating()).toLowerCase().contains(filterString))
                
                    currentMovieList.add(movie);
                
                else if (movie.getGenre().toString().toLowerCase().contains(filterString))
                
                    currentMovieList.add(movie);
                
            
            adapter.notifyDataSetChanged();
            //FLAGS Cannot resolve method 'getFilter()' here
        

        @Override
        public void beforeTextChanged(CharSequence arg0, int arg1, int arg2,int arg3) 
            // TODO Auto-generated method stub

        

        @Override
        public void afterTextChanged(Editable arg0) 
            // TODO Auto-generated method stub
        
    );

并将其添加到您的 CustomListAdapter

public class CustomListAdapter extends BaseAdapter implements Filterable 

    private Activity activity;
 private LayoutInflater inflater;

 private List<String>originalData = null;
 // private List<String>filteredData = null;

 private List<Movie> movieItems;
 private List<Movie> originalMovieList;
 private String[] bgColors;
 ImageLoader imageLoader = MyApplication.getInstance().getImageLoader();
 private ItemFilter mFilter = new ItemFilter();


 public CustomListAdapter(Activity activity, List<Movie> movieItems) 
       this.activity = activity;
        this.movieItems = movieItems;
      // this.originalMovieList = movieItems;
      this.originalMovieList = new ArrayList<Movie>(movieItems);
      bgColors = activity.getApplicationContext().getResources().getStringArray(R.array.movie_serial_bg);
        

    //Add Below Method
    public void reloadData()
       this.originalMovieList = new ArrayList<Movie>(movieItems);
     notifyDataSetChanged();
        
     @Override
 public int getCount() 
     return movieItems.size();
        

 @Override
    public Object getItem(int location) 
        return movieItems.get(location);
        

    @Override
    public long getItemId(int position) 
       return position;
        

 @Override
    public View getView(int position, View convertView, ViewGroup parent) 

     if (inflater == null)
        inflater = (LayoutInflater) activity
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    if (convertView == null)
        convertView = inflater.inflate(R.layout.list_row_image, null);

    if (imageLoader == null)
        imageLoader = MyApplication.getInstance().getImageLoader();
    NetworkImageView thumbNail = (NetworkImageView) convertView.findViewById(R.id.thumbnail);

    TextView serial = (TextView) convertView.findViewById(R.id.serial);
    TextView title = (TextView) convertView.findViewById(R.id.title);
    TextView rating = (TextView) convertView.findViewById(R.id.rating);
    TextView genre = (TextView) convertView.findViewById(R.id.genre);
    TextView year = (TextView) convertView.findViewById(R.id.releaseYear);

    // getting movie data for the row
    Movie m = movieItems.get(position);

    // thumbnail image
    thumbNail.setImageUrl(m.getThumbnailUrl(), imageLoader);

    // title
    title.setText(m.getTitle());

    // rating
    rating.setText("Rating: " + String.valueOf(m.getRating()));

     // genre
     String genreStr = "";
        for (String str : m.getGenre()) 
          genreStr += str + ", ";
     
     genreStr = genreStr.length() > 0 ? genreStr.substring(0,
            genreStr.length() - 2) : genreStr;
        genre.setText(genreStr);

        // release year
     year.setText(String.valueOf(m.getYear()));

     String color = bgColors[position % bgColors.length];
        serial.setBackgroundColor(Color.parseColor(color));




      return convertView;
 


            public Filter getFilter() 
                return mFilter;
            

            private class ItemFilter extends Filter 
                @Override
                protected FilterResults performFiltering(CharSequence constraint) 

                    String filterString = constraint.toString().toLowerCase();

                    FilterResults results = new FilterResults();


                    //results.values = nlist;
                    //results.count = nlist.size();
                    results.values = originalMovieList;
                    results.count = originalMovieList.size();

                    return results;
                

                @SuppressWarnings("unchecked")
                @Override
                protected void publishResults(CharSequence constraint, FilterResults results) 
                    //filteredData = (ArrayList<String>) results.values;
                    //movieItems = (ArrayList<Movie>) results.values;
                    movieItems.clear();
                    movieItems.addAll((ArrayList<Movie>) results.values);
                    notifyDataSetChanged();
                

            

现在这是一个 WRAP。 感谢@DhavalPatel 那家伙是 android 大师。 He made all this happen. -Happy Coding