Retrieving Document Id from Firestore Collection (Android)

Question

I\'m trying to extract the auto-generated Id under a document so I can use it elsewhere.

Here is the full code:

mStartChatButton.setOnClickListener(new V         


        

Answer 1

1) The line of code I'm using to extract the document Id is not working and is extracting some other new auto-generated id (I'm guessing it is because I'm using the .document() method before the .getId() method).

No, this is happening because you are calling CollectionReference's document() method twice:

Returns a DocumentReference pointing to a new document with an auto-generated ID within this collection.

So every time you are calling document() method, a fresh new id is generated. To solve this, please change the following lines of code:

mWhammyUsersCollection.document(mCurrentUserId).collection("my-chats")
                .document().set(myChatFields)
                .addOnSuccessListener(/* ... */);

to

String id = mWhammyUsersCollection.document(mCurrentUserId).collection("my-chats")
                .document().getId();
mWhammyUsersCollection.document(mCurrentUserId).collection("my-chats")
                .document(id).set(myChatFields)
                .addOnSuccessListener(/* ... */);

See, I have used the id that was generated first time inside the refernce. Now inside the onSuccess() method, you should use the same id that was generated above:

myChatFields.put("chatCardId", id);

And not a newer one, as you do in your actual code.

2) Also the information for some reason does not get added to the HashMap with the last line of code I put.

This is happening becase you are using a wrong reference. Using a reference that contains the correct id will solve your problem.