在用户之间检索Firebase数据

我希望能够始终在用户之间检索消息，但是当我专门引用我在向后端添加新消息时创建的子节点时，我似乎只能这样做（子节点是“USER1PHONENUMBER：USER2PHONENUMBER” “并且两个用户都将数据写入同一子节点 . 这适用于当用户进入联系人列表并选择联系人时，因为我可以获得两个用户电话号码并知道要使用哪个子节点 . 我这样做了：

if (senderNumber > receiverNumber) {
            Firebase ref = new Firebase(Passwords.FB_LINK).child("Message").child(username + ":" + binderContact.getNumber());

            ref.addValueEventListener(new ValueEventListener() {
                @Override
                public void onDataChange(DataSnapshot dataSnapshot) {
                    for (DataSnapshot msg : dataSnapshot.getChildren()) {
                        Message message = msg.getValue(Message.class);
                        Log.d("TAG", "Message Received: " + message.getText());
                    }
                }

                @Override
                public void onCancelled(FirebaseError firebaseError) {

                }
            });
        }
        else {
            Firebase ref = new Firebase(Passwords.FB_LINK).child("Message").child(binderContact.getNumber() + ":" + username);

            ref.addValueEventListener(new ValueEventListener() {
                @Override
                public void onDataChange(DataSnapshot dataSnapshot) {
                    for (DataSnapshot msg : dataSnapshot.getChildren()) {
                        Message message = msg.getValue(Message.class);
                        Log.d("TAG", "Message Received: " + message.getText());
                    }
                }

                @Override
                public void onCancelled(FirebaseError firebaseError) {

                }
            });
        }

事情是，我希望以某种方式接收消息，我的用户在子节点上收到一条新消息，这会留下他们的电话号码，然后我可以存储它并将其显示在列表视图中，并附上联系方式，这样我就可以创建一个消息 . 用户手机随时收到新消息的通知 . 任何想法如何实现这一点？我现在真的没有任何想法 .

我有以下Messages类结构：

public class Message {
    private String from;
    private String to;
    private String text;
    private String time;
    private String timeCreated;
    private Boolean repeat;
    private String weekdays;
    public Message() {}

    public Message(String from, String to, String text, String time, String timeCreated, Boolean repeat, String weekdays) {
        this.from = from;
        this.to = to;
        this.text = text;
        this.time = time;
        this.timeCreated = timeCreated;
        this.repeat = repeat;
        this.weekdays = weekdays;
    }
    public String getFrom() {
        return from;
    }
    public String getTo() {
        return to;
    }
    public String getText() {
        return text;
    }
    public String getTime() {
        return time;
    }
    public String getTimeCreated() {
        return timeCreated;
    }
    public Boolean getRepeat() {
        return repeat;
    }
    public String getWeekdays() {
        return weekdays;
    }


}

这就是我将数据保存到firebase的方式以及它在firebase end上的样子（用户名=用户的phonenumber）：

// Save message on backend
                if (senderNumber > receiverNumber) {
                    Firebase ref = new Firebase(Passwords.FB_LINK).child("Message").child(username + ":" + binderContact.getNumber()).child(currentTimeStamp);
                    Message msg = new Message(username, binderContact.getNumber(), message, hour + ":" + minute, currentTimeStamp, repeat, "M, D, W");
                    ref.setValue(msg);
                }
                else {
                    Firebase ref = new Firebase(Passwords.FB_LINK).child("Message").child(binderContact.getNumber() + ":" + username).child(currentTimeStamp);
                    Message msg = new Message(username, binderContact.getNumber(), message, hour + ":" + minute, currentTimeStamp, repeat, "M, D, W");
                    ref.setValue(msg);
                }