如何根据ListActivity中长按的项目设置特定的上下文菜单？

ListView listView = getListView();
registerForContextMenu(listView);

@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
    super.onCreateContextMenu(menu, v, menuInfo);
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.context_menu, menu);
}

<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <item
        android:id="@+id/menu_edit"
        android:title="编辑" />
    <item
        android:id="@+id/menu_delete"
        android:title="删除" />
</menu>

@Override
public boolean onContextItemSelected(MenuItem item) {
    AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo) item.getMenuInfo();
    int position = info.position;
    switch (item.getItemId()) {
        case R.id.menu_edit:
            // 编辑操作
            editItem(position);
            return true;
        case R.id.menu_delete:
            // 删除操作
            deleteItem(position);
            return true;
        default:
            return super.onContextItemSelected(item);
    }
}