Android Data Binding SetSupportActionBar

Make project in Android Studio then you can use below code for accessing toolbar:

ActivityMainBinding binding = DataBindingUtil.setContentView(this, R.layout.activity_main);
setSupportActionBar(binding.toolbar);

You can access the instance of the toolbar using views by id function

<android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            app:layout_scrollFlags="scroll|enterAlways"
            app:popupTheme="@style/AppTheme.PopupOverlay" />

then on your onCreate() method do the following

ActivityGalleryBinding binding = DataBindingUtil
    .setContentView(this, R.layout.activity_gallery);
binding.setViewModel(new GalleryModel(this));
//set it like this
setSupportActionBar(binding.<location>.<of>.<your>.toolbar);

if your toolbar is inside other xml component (referenced with <include/>) you still can access it as long as you provide and @id to the <include/>