Android, add() function of ArrayAdapter not working

Question

I have an ArrayAdapter (myAdapter) attached to an AutoCompleteTextView (textView) component.
Once the user presses a character I would like to populate AutoCompleteTextView\

Answer 1

I had the exact same problem. After examining the ArrayAdapter and AutoCompleteTextView source code, I found out that the problem was, in short, that:

• the original object list is stored in ArrayAdapter.mObjects.
• However, AutoCompleteTextView enables ArrayAdapter's filtering, meaning that new objects are added to ArrayAdapter.mOriginalValues, while mObjects contains the filtered objects.
• ArrayAdapter.getCount() always returns the size of mObjects.

My solution was to override ArrayAdapter.getFilter() to return a non-filtering filter. This way mOriginalValues is null and mObjects is used instead in all cases.

Sample code:

public class MyAdapter extends ArrayAdapter {
    NoFilter noFilter;
    /*
    ...
    */

    /**
     * Override ArrayAdapter.getFilter() to return our own filtering.
     */
    public Filter getFilter() {
        if (noFilter == null) {
            noFilter = new NoFilter();
        }
        return noFilter;
    }

    /**
     * Class which does not perform any filtering.
     * Filtering is already done by the web service when asking for the list,
     * so there is no need to do any more as well.
     * This way, ArrayAdapter.mOriginalValues is not used when calling e.g.
     * ArrayAdapter.add(), but instead ArrayAdapter.mObjects is updated directly
     * and methods like getCount() return the expected result.
     */
    private class NoFilter extends Filter {
        protected FilterResults performFiltering(CharSequence prefix) {
            return new FilterResults();
        }

        protected void publishResults(CharSequence constraint,
                                      FilterResults results) {
            // Do nothing
        }
    }
}