Get the pushed ID for specific value in firebase android

UPDATE 1: it can obtain also by one line

String key = mDatabase.child("posts").push().getKey();

//**************************************************************//

after searching and trying a lot of things i came to 2 ways to do that . 1. first one to get the key when i upload the post to the server via this function

 public void uploadPostToFirebase(Post post) {
      DatabaseReference mFirebase = mFirebaseObject
            .getReference(Constants.ACTIVE_POSTS_KEY)
            .child(post.type);
      mFirebase.push().setValue(post);
      Log.d("Post Key" , mFirebase.getKey());
 }

1. i used it in my code to get the key after i have already pushed it to node for it in my database

   public void getUserKey(String email) {
   
       Query queryRef = databaseRef.child(Constants.USERS_KEY)
           .orderByChild(Constants.USERS_EMAIL)
           .equalTo(email);
   
       queryRef.addChildEventListener(new ChildEventListener() {
         @Override
         public void onChildAdded(DataSnapshot dataSnapshot, String s) {
           //TODO auto generated
         }
   
         @Override
         public void onChildChanged(DataSnapshot dataSnapshot, String s) {
           //TODO auto generated;
         }
   
         @Override
         public void onChildRemoved(DataSnapshot dataSnapshot) {
           //TODO auto generated;
         }
   
         @Override
         public void onChildMoved(DataSnapshot dataSnapshot, String s) {
           //TODO auto generated
         }
   
         @Override
         public void onCancelled(DatabaseError databaseError) {
           //TODO auto generated 
         }
     });
    }
   

You can read the key from push() without pushing the values. Later you can create a child with that key and push the values for that key.

// read the index key
String mGroupId = mGroupRef.push().getKey();
....
....
// create a child with index value
mGroupRef.child(mGroupId).setValue(new ChatGroup());

mGroupId contains the key which is used to index the value you're about to save.