How can I create a unique key and use it to send data in Firebase?

Question

I'm using Firebase in my project and I was trying to create a unique key using Firebase. Using this key I wanna send posts when user start the activity. Like this:

 "Posts"
     |
      -> "Parent Unique key"
                 |
                 -> "child unique key 1"
                 -> "child unique key 2"
                 -> "child unique key 3"
                 ...

I wanna create Parent Unique key and by using it I wanna send posts. I know how to create unique key in firebase using push() but the problem is when user restart the activity, a new unique key will generate. I don't wanna create the same parent key again after creating once and I can't use user_id here as multiple users have different ids. Also I don't wanna store the parent key in some storage medium. Is it possible to create such key in firebase?

Answer 1

If you do this inside onCreate() method:

DatabaseReference ref=FirebaseDatabase.getInstance().getReference().child("Posts").push();

then yes, everytime you enter that activity a new push id will be created. This is because push() generates a random id.

To be able to solve this, you need to add push() later on.. or under a condition but not at the beginning.

So you can add it onClick of a button:

 ref.push().child("name").setValue(name);

This way everytime you click a button it will generate a push id, not when you restart the activity.

Answer 2

To solve this, please use the following code:

DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
String uniqueKey = rootRef.child("Posts").push().getKey();
DatabaseReference uniqueKeyRef = rootRef.child("Posts").child(uniqueKey);

So for adding data, use only uniqueKeyRef reference. So, using this code you'll create a unique id only once. You'll be able to add those childs under a single id.

If you want another key, see UUID which can help you generate unique keys for your Firebase database without having to use the push() method.