[Catalog] Fix flickering AppBarLayout in Navigation Rail demo

Resolves #3925

PiperOrigin-RevId: 591264750

Author: dsn5ft

catalog/java/io/material/catalog/feature/DemoFragment.java

@@ -31,10 +31,12 @@
 import android.view.MenuItem;
 import android.view.View;
 import android.view.ViewGroup;
+import androidx.annotation.IdRes;
 import androidx.annotation.Nullable;
 import androidx.annotation.StringRes;
 import androidx.coordinatorlayout.widget.CoordinatorLayout;
 import androidx.core.view.ViewCompat;
+import com.google.android.material.appbar.AppBarLayout;
 import com.google.android.material.appbar.AppBarLayout.ScrollingViewBehavior;
 import dagger.android.AndroidInjector;
 import dagger.android.DispatchingAndroidInjector;
@@ -94,6 +96,12 @@ public View onCreateView(
     ((CoordinatorLayout.LayoutParams) demoView.getLayoutParams())
         .setBehavior(new ScrollingViewBehavior());
 
+    int liftOnScrollTargetViewId = getLiftOnScrollTargetViewId();
+    if (liftOnScrollTargetViewId != View.NO_ID) {
+      AppBarLayout appBarLayout = view.findViewById(R.id.cat_demo_fragment_appbar);
+      appBarLayout.setLiftOnScrollTargetViewId(liftOnScrollTargetViewId);
+    }
+
     ViewGroup children = (ViewGroup) demoContainer.getChildAt(0);
     DemoUtils.addBottomSpaceInsetsIfNeeded(children, demoContainer);
     return view;
@@ -113,6 +121,11 @@ public boolean shouldShowDefaultDemoActionBar() {
     return true;
   }
 
+  @IdRes
+  public int getLiftOnScrollTargetViewId() {
+    return View.NO_ID;
+  }
+
   @Override
   public AndroidInjector<Object> androidInjector() {
     return childFragmentInjector;

catalog/java/io/material/catalog/navigationrail/NavigationRailDemoControlsFragment.java

@@ -55,6 +55,11 @@ protected int getNavigationRailDemoControlsLayout() {
     return R.layout.cat_navigation_demo_controls;
   }
 
+  @Override
+  public int getLiftOnScrollTargetViewId() {
+    return R.id.cat_navigation_rail_nested_scroll_view;
+  }
+
   private void initAddRemoveHeaderViewButtons(View view) {
     final Button addHeaderViewButton = view.findViewById(R.id.add_header_view_button);
     final Button removeHeaderViewButton = view.findViewById(R.id.remove_header_view_button);

catalog/java/io/material/catalog/navigationrail/res/layout/cat_navigation_rail_fragment.xml

@@ -30,6 +30,7 @@
     android:fitsSystemWindows="false"/>
 
   <androidx.core.widget.NestedScrollView
+      android:id="@+id/cat_navigation_rail_nested_scroll_view"
       android:layout_width="0dp"
       android:layout_height="wrap_content"
       android:layout_weight="1"