问Android Cloud Firestore将新项目添加到文档子列表

EN

  db = FirebaseFirestore.getInstance();
    String userid = FirebaseAuth.getInstance().getCurrentUser().getUid();

    db.collection("Users").document(userid);

    Map<String, Object> docData = new HashMap<>();

    Map<String, Object> nestedData = new HashMap<>();
    nestedData.put("Ernährung2", true);


    docData.put("channelAbos", nestedData);
    db.collection("Users").document(FirebaseAuth.getInstance().getCurrentUser().getUid())
    .set(docData);