Eine Ausnahme ist aufgetreten während performFiltering() für ListView

Question

Ich habe ListView erstellt und ich möchte Suchfilter auf diese Listenansicht anwenden. Ich habe den Code wie unten aufgeführt. aber es zeigt Fehler in Logcat wie unten während PerformFiltering().

Logcat

W/PathParser: Points are too far apart 4.000000596046461 
W/Filter: An exception occurred during performFiltering()! 
      java.lang.NullPointerException: collection == null 
       at java.util.ArrayList.<init>(ArrayList.java:94) 
       at com.example.chaitanya.nearbyplace.CustomBaseAdapter$1.performFiltering(CustomBaseAdapter.java:156) 
       at android.widget.Filter$RequestHandler.handleMessage(Filter.java:234) 
       at android.os.Handler.dispatchMessage(Handler.java:102) 
       at android.os.Looper.loop(Looper.java:135) 
       at android.os.HandlerThread.run(HandlerThread.java:61) 
D/android.widget.Filter$FilterResults@39681f38: FilterResult 

CustomeBaseAdapter

public class CustomBaseAdapter extends BaseAdapter implements Filterable { 
    Context context; 
    List<RowItem> rowItems; 

    List<String> arrayList; 
    List<String> mOriginalValues; // Original Values 
    LayoutInflater inflater; 




    public CustomBaseAdapter(Context context, List<RowItem> items) { 
     this.context = context; 
     this.rowItems = items; 
    } 

    /*private view holder class*/ 
    private class ViewHolder { 
     ImageView imageView; 
     TextView txtTitle; 
    } 

    public View getView(int position, View convertView, ViewGroup parent) { 
     ViewHolder holder = null; 

     LayoutInflater mInflater = (LayoutInflater) 
       context.getSystemService(Activity.LAYOUT_INFLATER_SERVICE); 
     if (convertView == null) { 
      convertView = mInflater.inflate(R.layout.list_item, null); 
      holder = new ViewHolder(); 
      holder.txtTitle = (TextView) convertView.findViewById(R.id.label); 
      holder.imageView = (ImageView) convertView.findViewById(R.id.icon); 
      convertView.setTag(holder); 
     } 
     else { 
      holder = (ViewHolder) convertView.getTag(); 
     } 

     RowItem rowItem = (RowItem) getItem(position); 

     holder.txtTitle.setText(rowItem.getTitle()); 
     holder.imageView.setImageResource(rowItem.getImageId()); 

     return convertView; 
    } 

    @Override 
    public int getCount() { 
     return rowItems.size(); 
    } 

    @Override 
    public Object getItem(int position) { 
     return rowItems.get(position); 
    } 

    @Override 
    public long getItemId(int position) { 
     return rowItems.indexOf(getItem(position)); 
    } 


    @Override 
    public Filter getFilter() { 
     Filter filter = new Filter() { 

      @SuppressWarnings("unchecked") 
      @Override 
      protected void publishResults(CharSequence constraint,FilterResults results) { 


       arrayList = (List<String>) results.values; // has the filtered values 
       notifyDataSetChanged(); // notifies the data with new filtered values 
      } 

      @Override 
      protected FilterResults performFiltering(CharSequence constraint) { 
       Log.d(constraint.toString(),"constraint"); 
       FilterResults results = new FilterResults();  // Holds the results of a filtering operation in values 
       List<String> FilteredArrList = new ArrayList<String>(); 

       if (mOriginalValues == null) { 
        mOriginalValues = new ArrayList<String>(arrayList); // saves the original data in mOriginalValues 
       } 

       /******** 
       * 
       * If constraint(CharSequence that is received) is null returns the mOriginalValues(Original) values 
       * else does the Filtering and returns FilteredArrList(Filtered) 
       * 
       ********/ 
       if (constraint == null || constraint.length() == 0) { 

        // set the Original result to return 
        results.count = mOriginalValues.size(); 
        results.values = mOriginalValues; 
       } else { 
        constraint = constraint.toString().toLowerCase(); 
        for (int i = 0; i < mOriginalValues.size(); i++) { 
         String data = mOriginalValues.get(i); 
         if (data.toLowerCase().contains(constraint.toString())) { 
          FilteredArrList.add(data); 
         } 
        } 
        // set the Filtered result to return 
        results.count = FilteredArrList.size(); 
        results.values = FilteredArrList; 
       } 
       return results; 
      } 
     }; 
     return filter; 
    } 


} 

MainActivity.java

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()); 
     // String text = inputSearch.getText().toString().toLowerCase(Locale.getDefault()); 
     //adapter.filter(text); 
    } 

    @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 
    } 
}); 

if (mOriginalValues == null) { mOriginalValues = new ArrayList<String>(arrayList); // saves the original data in mOriginalValues } in diesem Block if (mOriginalValues == null) { ist die Linie 156 in CustomeBaseAdapter.

Answer 1

Ihr arrayList scheint Null.

aktualisieren CustomBaseAdapter Konstruktor wie folgt:

public CustomBaseAdapter(Context context, List<RowItem> items) { 
     this.context = context; 
     this.rowItems = items; 

     arrayList = new ArrayList<String>(); 
     for(int i = 0; i < rowItems.size(); i++) 
     { 
      RowItem rowItem = (RowItem) getItem(position); 
      arrayList.add(rowItem.getTitle()); 
     } 
    } 

In performFiltering dies tun:

........... 
....................... 

if (mOriginalValues == null) { 
    mOriginalValues.addAll(arrayList); // saves the original data in mOriginalValues 
} 
............ 
...................