搜索ListView不起作用-为什么？

List<String> items = Arrays.asList("Item 1", "Item 2", "Item 3");
ArrayAdapter<String> adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, items);
listView.setAdapter(adapter);

public class CustomAdapter extends ArrayAdapter<String> {
    public CustomAdapter(Context context, List<String> items) {
        super(context, 0, items);
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        if (convertView == null) {
            convertView = LayoutInflater.from(getContext()).inflate(android.R.layout.simple_list_item_1, parent, false);
        }
        TextView textView = convertView.findViewById(android.R.id.text1);
        textView.setText(getItem(position));
        return convertView;
    }
}

<ListView
    android:id="@+id/listView"
    android:layout_width="match_parent"
    android:layout_height="match_parent"/>

public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        ListView listView = findViewById(R.id.listView);
        List<String> items = Arrays.asList("Item 1", "Item 2", "Item 3");
        ArrayAdapter<String> adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, items);
        listView.setAdapter(adapter);
    }
}