Errors with custom BaseAdapter for AutoCompleteTextView(indexOutOfBounds & content changed but no notification)

Question

I have created my own adapter which extends BaseAdapter implements Filterable.

I am occasionally getting index out of bounds error, in getView method:

    private ArrayList<ResultHolderData> originalData;
private ArrayList<ResultHolderData> arrayList;
private LayoutInflater inflater;
private ArrayList<ResultHolderData> suggestions;


public static class ResultHolderData {
    public String symbol;
    public String fullName;
    public ResultHolderData(String a, String b) {
        symbol=a;
        fullName=b;
    }
}

public static class ResultHolder {
    public TextView symName;
    public TextView symNameFull;
}
    @Override
public View getView(int position, View convertView, ViewGroup parent) {
    ResultHolder rh;

    if(convertView==null) {
        rh=new ResultHolder();
        convertView=inflater.inflate(R.layout.two_line_dropdown_item, null);
        rh.symName=(TextView) convertView.findViewById(R.id.autocompleteSym);
        rh.symNameFull=(TextView) convertView.findViewById(R.id.autocompleteName);
        convertView.setTag(rh);
    } else {
        rh=(ResultHolder) convertView.getTag();
    }

    //rh.symName.setTextColor(Color.GREEN);

     /***THE BELLOW LINE THROWS THE ERROR***/
    rh.symName.setText(arrayList.get(position).symbol);
    rh.symNameFull.setText(arrayList.get(position).fullName);
    //rh.symName.setText(arrayList.get(position));

    return convertView;
}

The arrayList represents the filtered resultSet:

            @SuppressWarnings("unchecked")
    @Override
    protected void publishResults(CharSequence constraint,FilterResults results) {
       if(results.count>0 && results!=null) {
           arrayList=(ArrayList<ResultHolderData>) results.values;
           notifyDataSetChanged();
       } else {
           notifyDataSetInvalidated();
       }

    }

The error occurs sometimes, when you have 2 items in dropdown suggestions and when typing another letter causes the dropdown to only suggest one item. Then it says: Invalid index 1, size is 1.

---

My opinion: It usually happens when i am typing in fast, so i assume that NotifyDataSetChanged is in progress, but the publishResults changes the content of the arrayList and this causes the error. But then again i would expect this to happen in more situations?

Also another error pops out: The content of the adapter has changed but ListView did not receive a notification. Make sure the content of your adapter is not modified from a background thread, but only from the UI thread.

Any thoughts?

Answer 1

The problem was this line in publishResults:

    arrayList=(ArrayList<ResultHolderData>) results.values;

which just pointed arrayList to those results, instead i made a "shallow copy" and cleared the list before it:

      arrayList.clear();
      for(ResultHolderData tempRhd : (ArrayList<ResultHolderData>)results.values)
               arrayList.add(tempRhd);

and problem solved!