android - How can I get data out of onDataChange method?

Question

Situation: I want to compare a url from my function parameter with a url retrieved from my firebase realtime database. The retrieval works, however, I don't know how else to get a boolean value from the String comparison in my if-else statement, in which I get an error of: "Cannot assign value to final variable 'bool' ".

compare() code:

private boolean compare(String url) {
    mDatabaseReference = mFirebaseDatabase.getReference("Executive Branch");
    final String newUrl = url;
    final boolean bool = false;

    mDatabaseReference.limitToFirst(1).addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            if (dataSnapshot.getChildrenCount() > 0) {
                for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
                    ExecutiveOrder executiveOrder = snapshot.getValue(ExecutiveOrder.class);
                    if (executiveOrder.getUrl().equals(newUrl)) {
                        bool = true;
                    } else {
                        bool = false;
                    }
                }
            }
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {
            Log.e("Executive Order", "The read failed: " + databaseError.getDetails());
        }
    });

    return bool;
}

Answer 1

Waitting for answers