Jamie22 Jamie22 -4 years ago 90
Android Question

Obtaining the reference and key in Custom Object Firebase Android

I'm looking to pass the reference of the dataSnapshot and key of each specific object into a custom 'Message' object.

I've tried using the key 'String key' within the Message.class but it appears to come back null.

Here is how my Message object currently is:

public class Message {

private String key;
private String sender_id;
private String sender_username;
private String receiver_username;
private String receiver_id;
private String chat_id;
private String message;
private Firebase ref;
private double createdAt;
private boolean read;

public Message() {
// empty default constructor, necessary for Firebase to be able to deserialize messages
}

public String getKey() { return key; }
public String getSender_id() { return sender_id; }
public String getSender_username() { return sender_username; }
public String getReceiver_username() { return receiver_username; }
public String getReceiver_id() { return receiver_id; }
public String getChat_id() { return chat_id; }
public String getMessage() { return message; }
public Firebase getRef() { return ref; }
public double getCreatedAt() { return createdAt; }
public boolean getRead() { return read; }

}


Any ideas, how I properly pass the dataSnapshot.getKey() String to the custom object? I don't see an example on the Firebase docs, and to be clear I'm using the "legacy Firebase", before they updated.

Answer Source

When you get a Message instance from a DataSnapshot, you are likely doing:

Message message = snapshot.getValue(Message.class)

Since this is starting from getValue(), the message will not contain the key of the DataSnapshot.

What you can do is set the key yourself after reading the Message:

Message message = snapshot.getValue(Message.class);
message.setKey(snapshot.getKey());

You'll want to mark the getKey() as @JsonIgnore in that case, to ensure that Jackson tries to auto-populate or serialize it.

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