activity_main.xml

<Button
        android:id="@+id/register"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Register"
        android:layout_gravity="center"
        android:layout_marginTop="5dp"
        android:onClick="@{() -> RegisterViewModel.onCLicked()}"
        bind:toastMessageAction="@{RegisterViewModel.toastMessage}"/>