Android Studio Filter, ListView With Perzonalized adapter

I have the next class

public class ContactsListDialog extends Dialog implements DialogInterface.OnClickListener  {

    private ListView list;
    private EditText filterText = null;
    AdapterMostrarContactos  adapter = null;
    private static final String TAG = "CityList";
    String[] aux ;
    Activity activity;

    ArrayList<String> contactosnNombre;
    ArrayList<String> contactosTele;
    ArrayList<String> contactosImg;
    ArrayList<Contacto> contactos = new ArrayList<Contacto>() ;

    public ContactsListDialog(Context context, String[] contactos, Activity activity,ArrayList<String> contactosnNombre,ArrayList<String> contactosTele,ArrayList<String> contactosImg) {
        super(context);
        aux = contactos;
        this.activity = activity;
        this.contactosImg = contactosImg;
        this.contactosnNombre = contactosnNombre;
        this.contactosTele = contactosTele;
        setContentView(R.layout.activity_dialogperzonalizate);
        this.setTitle("Seleccionar Contacto");
        filterText = (EditText) findViewById(R.id.EditBox);
        filterText.addTextChangedListener(filterTextWatcher);
        list = (ListView) findViewById(R.id.List);
      //  adapter = new ArrayAdapter<String>(context, android.R.layout.simple_list_item_1, contactos);


        int cantidad = contactosnNombre.size();
        int iterador = 0 ;

        while(iterador<cantidad){
        Contacto aux = new Contacto(contactosnNombre.get(iterador),contactosTele.get(iterador), Uri.parse(contactosImg.get(iterador)));

        this.contactos.add(aux);
            iterador++;
        }

     adapter = new AdapterMostrarContactos(activity,this.contactos);




        list.setAdapter(adapter);
        list.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> a, View v, int position, long id) {

            }
        });
    }
    @Override
    public void onClick(DialogInterface dialogInterface, int i) {

    }

    private TextWatcher filterTextWatcher = new TextWatcher() {

        public void afterTextChanged(Editable s) {
        }

        public void beforeTextChanged(CharSequence s, int start, int count,
                                      int after) {
        }

        @Override
        public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
          adapter.getFilter(adapter).filter(filterText.getText().toString());
        }

    };



}

which has an EDITBOX and a LISTVIEW as layout, this is the layout

<EditText android:id="@+id/EditBox"
    android:maxLines="1"
    android:layout_height="wrap_content"
    android:layout_width="270dp"
    android:layout_marginRight="70dp"
    android:layout_marginLeft="30dp">
</EditText>
<ListView android:id="@+id/List"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:choiceMode="singleChoice"

    >
</ListView>

The listView has the following perzonalized adapter,

this is the class

class AdapterMostrarContactos extends BaseAdapter {

protected Activity activity ;

ArrayList<Contacto> contactos;



public AdapterMostrarContactos(Activity activity,  ArrayList<Contacto> contactos){
this.activity = activity;
    this.contactos = contactos;
}

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

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

@Override
public long getItemId(int position) {
    return contactos.get(position).getId();
}

@Override
public View getView(int position, View contentView, ViewGroup parent) {
    View vi=contentView;


        LayoutInflater inflater = (LayoutInflater) activity
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        vi = inflater.inflate(R.layout.activity_listado_confoto_, null);

    TextView nombre = (TextView) vi.findViewById(R.id.texto_principal);
    TextView telefono = (TextView) vi.findViewById(R.id.texto_secundario);
    ImageView Img = (ImageView) vi.findViewById(R.id.icon);

    Contacto item = contactos.get(position);

    nombre.setText(item.getNombre());

    telefono.setText(item.getTelefono());

    Img.setImageURI(item.getImagen());


    return vi;
}

public Filter getFilter(final AdapterMostrarContactos adapter ) {


    Filter filter = new Filter() {

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

            List<String> arrayListNames = (List<String>) results.values;
            adapter.notifyDataSetChanged();
        }
        @Override
        protected FilterResults performFiltering(CharSequence constraint) {

            FilterResults results = new FilterResults();
            ArrayList<String> FilteredArrayNames = new ArrayList<String>();

            // perform your search here using the searchConstraint String.

            constraint = constraint.toString().toLowerCase();
            for (int i = 0; i < contactos.size(); i++) {
                String dataNames = contactos.get(i).getNombre();
                if (dataNames.toLowerCase().startsWith(constraint.toString())) {
                    FilteredArrayNames.add(dataNames);
                }
            }

            results.count = FilteredArrayNames.size();
            results.values = FilteredArrayNames;
            //Log.e("VALUES", results.values.toString());

            return results;
        }
    };

    return filter;

}

this is the adapter layout

<?xml version="1.0" encoding="utf-8"?>

<ImageView
    android:id="@+id/icon"
    android:layout_width="60dp"
    android:layout_height="60dp"
    android:padding="5dp"
    />

<LinearLayout android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="vertical">

    <TextView
        android:id="@+id/texto_principal"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Medium Text"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:layout_marginLeft="10dp"
        android:layout_marginTop="5dp"
        android:padding="2dp"
        android:textColor="#489e37" />
    <TextView
        android:id="@+id/texto_secundario"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="TextView"
        android:layout_marginLeft="10dp"/>
</LinearLayout>

the issue is that the listview is not filtering me, currently it looks like this and I would like to be able to filter it,