ListView Android

private ListView listCategories;
    ArrayAdapter<String> adaptador;
    private String[] categorieslist;

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

        listCategories = (ListView)findViewById(R.id.listView_categories);

        categorieslist = new String[3];

        categorieslist = new String[3];
        categorieslist[0] = "category";
        categorieslist[1] = "category";
        categorieslist[2] = "category";

        adaptador = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1, categorieslist);

        listCategories.setAdapter(adaptador);

    }