Фильтрация списка не работает - Android

Я привязываюсь к реализации функции поиска в своем приложении. Я использую пользовательский ArrayAdapter<String> для listview, так как у меня есть два textViews подряд. Мое приложение не закрывается принудительно, но поиск не работает должным образом. Он не фильтрует представление списка, но когда я набираю что-то, чего нет в представлении списка, он правильно показывает страницу, на которой нет найденных элементов. Что могло быть не так? Вот код. Пожалуйста, наведите меня на правильный путь!

MainActivity.java

public class MainActivity extends Activity {
final String[] elename ={"Hydrogen","Helium","Lithium","Beryllium","Boron","Carbon","Nitrogen","Oxygen","Fluorine","Neon","Sodium","Magnesium","Aluminium","Silicon","Phosphorous","Sulphur","Chlorine","Argon","Potassium","Calcium","Scandium","Titanium","Vanadium","Chromium","Manganese","Iron","Cobalt","Nickel","Copper","Zinc","Gallium","Germanium","Arsenic","Selenium","Bromine","Krypton","Rubidium","Strontium","Yttrium","Zirconium","Niobium","Molybdenum","Technetium","Ruthenium","Rhodium","Palladium","Silver","Cadmium","Indium","Tin","Antimony","Tellurium","Iodine","Xenon","Caesium","Barium","Lanthanum","Cerium","Praseodymium","Neodymium","Promethium","Samarium","Europium","Gadolinium","Terbium","Dysprosium","Holmium","Erbium","Thulium","Ytterbium","Lutetium","Hafnium","Tantalum","Tungsten","Rhenium","Osmium","Iridium","Platinum","Gold","Mercury","Thallium","Lead","Bismuth","Polonium","Astatine","Radon","Francium","Radium","Actinium","Thorium","Protactinium","Uranium","Neptunium","Plutonium","Americium","Curium","Berkelium","Californium","Einsteinium","Fermium","Mendelevium","Nobelium","Lawrencium","Rutherfordium","Dubnium","Seaborgium","Bohrium","Hassium","Meitnerium","Darmstadtium","Roentgenium","Copernicium","Ununtrium","Ununquadium","Ununpentium","Ununhexium","Ununseptium","Ununoctium"};
final String[] nos = {"1","2","3","4","5","6","7","8","9","10","11","12","13","14","15","16","17","18","19","20","21","22","23","24","25","26","27","28","29","30","31","32","33","34","35","36","37","38","39","40","41","42","43","44","45","46","47","48","49","50","51","52","53","54","55","56","57","58","59","60","61","62","63","64","65","66","67","68","69","70","71","72","73","74","75","76","77","78","79","80","81","82","83","84","85","86","87","88","89","90","91","92","93","94","95","96","97","98","99","100","101","102","103","104","105","106","107","108","109","110","111","112","113","114","115","116","117","118"};
CustomAdapter cus;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    final EditText searchBar = (EditText) findViewById(R.id.searchbar);
    final DrawerLayout drawer = (DrawerLayout)findViewById(R.id.drawer_layout);
    final ListView navList = (ListView) findViewById(R.id.left_drawer);
    final LinearLayout linearLayout = (LinearLayout)findViewById(R.id.left_drawer_layout);
    cus = new CustomAdapter(MainActivity.this,elename,nos);
    navList.setAdapter(cus);


    navList.setOnItemClickListener(new AdapterView.OnItemClickListener(){
        @Override
        public void onItemClick(AdapterView<?> parent, View view, final int pos,long id){
            //Change view according to numbers

            drawer.closeDrawer(linearLayout);
        }
    });

    //filter list view after search instantly
    searchBar.addTextChangedListener(new TextWatcher() {

        @Override
        public void onTextChanged(CharSequence cs, int arg1, int arg2, int arg3) {
            // When user changed the Text
            MainActivity.this.cus.getFilter().filter(cs);
        }

        @Override
        public void beforeTextChanged(CharSequence arg0, int arg1, int arg2,int arg3) {

        }

        @Override
        public void afterTextChanged(Editable s) {
        }
    });

    //hide the keyboard after search on touch list view
    navList.setOnScrollListener(new AbsListView.OnScrollListener() {
        public void onScrollStateChanged(AbsListView view, int scrollState) {
            //hide keyboard
            InputMethodManager imm = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
            imm.hideSoftInputFromWindow(navList.getWindowToken(), 0);
        }

        public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
        }
    });

    navList.setEmptyView(findViewById(R.id.empty));

}
}

CustomAdapter.java

class CustomAdapter extends ArrayAdapter<String>
{
String A[],B[];
LayoutInflater mInflater;
public CustomAdapter(Context context, String[] A,String B[])
{
    super(context,R.layout.list_item,A);
    this.A = A;
    this.B = B;
    mInflater = LayoutInflater.from(context);
}
public View getView(int position, View convertView, ViewGroup parent) {
    ViewHolder holder;
    if(convertView==null)
    {
        convertView = mInflater.inflate(R.layout.list_item,parent,false);
        holder = new ViewHolder();
        holder.tv1 = (TextView)convertView.findViewById(R.id.element_name);
        holder.tv2 = (TextView)convertView.findViewById(R.id.element_nos);
        convertView.setTag(holder);
    }else{
        holder = (ViewHolder)convertView.getTag();
    }

    holder.tv1.setText(A[position]);
    holder.tv2.setText(B[position]);
    return convertView;
}
static class ViewHolder
{
    TextView tv1,tv2;
}
}

РЕДАКТИРОВАТЬ: принудительное закрытие приложения после реализации интерфейса.

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.Chinmay.navigationdrawer/com.Chinmay.navigationdrawer.MainActivity}: java.lang.ClassCastException: com.Chinmay.navigationdrawer.MainActivity
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1651)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1667)
    at android.app.ActivityThread.access$1500(ActivityThread.java:117)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:935)
    at android.os.Handler.dispatchMessage(Handler.java:99)
    at android.os.Looper.loop(Looper.java:130)
    at android.app.ActivityThread.main(ActivityThread.java:3687)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:507)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625)
    at dalvik.system.NativeStart.main(Native Method)
    Caused by: java.lang.ClassCastException: com.Chinmay.navigationdrawer.MainActivity
    at com.Chinmay.navigationdrawer.MainActivity.onCreate(MainActivity.java:49)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1615)