Question

I have an EditText component that searches a list using a custom adapter. It works fine except that the filtered views remain on screen. If the user deletes all the text in the edit box, I would like the full list to return to the screen.

I’ve tried three approaches:

1. I put a condition in my adapter’s filter classs. Placeing notifyDataSetChanged(); in FilterResults function, and it crashes the program.

2. Detecting if the EditTtext box is empty in the Activity, and then calling notifyDataSetChanged();. The condition works because I see System.out.println() prints text to the console. but it has no effect on the listView. Only the filtered text remains on screen.

3. Placing notifyDataSetChanged(); in OnTextChanged(). This also has no effect on resetting the listview.

How do I get the listview to reset when the EditText Box is empty?

Code from Activity:

// in OnCreate

if (searchBox.toString().equals("")){
                objAdapter.notifyDataSetChanged();


            }


        searchBox.addTextChangedListener(new TextWatcher(){

                @Override
                public void afterTextChanged(Editable arg0) {
                    // Do nothing
                }

                @Override
                public void beforeTextChanged(CharSequence s, int start, int count, int after) {
                    // Do nothing
                }

                @Override
                public void onTextChanged(CharSequence s, int start, int before, int count) {
                    objAdapter.getFilter().filter(s);

if (s.toString().equals("")){

                        // objAdapter.notifyDataSetChanged(); fails here 

}

                    }
                }

            });

Code from Adapter.

    public class NewsRowAdapter extends ArrayAdapter<Item> {
    //.... code
    private class ListFilter extends Filter
        {
                @Override
                protected FilterResults performFiltering(CharSequence constraint)
                {   
                    FilterResults results = new FilterResults();
                    String prefix = constraint.toString().toLowerCase();

                    if (prefix == null || prefix.length() == 0)
                    {

                        System.out.println("editText is empty");
                        // notifyDataSetChanged(); no effect

                        ArrayList<Item> list = new ArrayList<Item>(original);
                        results.values = list;
                        results.count = list.size();


                    }
                    else
                    {
                        final ArrayList<Item> list = original;

                        int count = list.size();
                        final ArrayList<Item> nlist = new ArrayList<Item>(count);

                        for (int i=0; i<count; i++)
                        {
                            final Item pkmn = list.get(i);
                            final String value = pkmn.getName().toLowerCase();
                        if (value.startsWith(prefix))
                        {
                            nlist.add(pkmn);
                        }
                    }
                    results.values = nlist;
                    results.count = nlist.size();
                }
                return results;
            }

            @SuppressWarnings("unchecked")
            @Override
            protected void publishResults(CharSequence constraint, FilterResults results) {
                fitems = (ArrayList<Item>)results.values;

                clear();
                int count = fitems.size();
                for (int i=0; i<count; i++)
                {
                    Item pkmn = (Item)fitems.get(i);
                    add(pkmn);
                }

                if (fitems.size() > 0){
                    notifyDataSetChanged();
                } else{
                    notifyDataSetInvalidated();
                }

            }

        }

Answer 1

Instead of searchBox.toString(), use searchBox.getText().toString()

searchBox.toString() is returning the object’s VM reference — which will never equal nothing