如何在自定义listview下方添加内容？

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

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

    <TextView
        android:id="@+id/bottomContent"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="下方内容" />

</LinearLayout>

public class CustomAdapter extends BaseAdapter {

    private List<String> data;

    public CustomAdapter(List<String> data) {
        this.data = data;
    }

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

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

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        if (convertView == null) {
            convertView = LayoutInflater.from(parent.getContext()).inflate(android.R.layout.simple_list_item_1, parent, false);
        }

        TextView textView = convertView.findViewById(android.R.id.text1);
        textView.setText(data.get(position));

        return convertView;
    }
}

public class MainActivity extends AppCompatActivity {

    private ListView listView;
    private TextView bottomContent;

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

        listView = findViewById(R.id.listView);
        bottomContent = findViewById(R.id.bottomContent);

        List<String> data = new ArrayList<>();
        data.add("Item 1");
        data.add("Item 2");
        data.add("Item 3");

        CustomAdapter adapter = new CustomAdapter(data);
        listView.setAdapter(adapter);
    }
}