example.java

public ObservableField<Integer> total = new ObservableField<>(); 

yourXML.xml

 <TextView android:layout_width="wrap_content"
           android:layout_height="wrap_content"
           android:text="@{total}"/>

<!-- I am used to have a viewModel for each class, so in such case it would be something like android:text="@{orderViewModel.total} but in your case I think @{total} is the right way -->