RT DB AddValueListener

  //Adding eventListener to that reference
        myRef.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                //Getting the string value of that node
                String value =  dataSnapshot.getValue(String.class);
                
                Toast.makeText(MainActivity.this, "Data Received: " + value, Toast.LENGTH_SHORT).show();

            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {
                Log.e(TAG, "onCancelled: Something went wrong! Error:" + databaseError.getMessage() );

            }
        });