CODE EXAMPLE FOR JAVA

constraintlayout vs coordinatorlayout

<androidx.coordinatorlayout.widget.CoordinatorLayout
 xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:app="http://schemas.android.com/apk/res-auto"
 android:layout_width="match_parent"
 android:layout_height="match_parent">

      <androidx.core.widget.NestedScrollView
         android:layout_width="match_parent"
         android:layout_height="match_parent"
         app:layout_behavior="com.google.android.material.appbar.AppBarLayout$ScrollingViewBehavior">

          <!-- Your scrolling content -->
          <androidx.constraintlayout.widget.ConstraintLayout
              ...>

              <!-- body of constraint layout -->

              <Button android:id="@+id/button" ...
              app:layout_constraintLeft_toLeftOf="parent"
              app:layout_constraintRight_toRightOf="parent/>


          </androidx.constraintlayout.widget.ConstraintLayout>
     </androidx.core.widget.NestedScrollView>

     <com.google.android.material.appbar.AppBarLayout
         android:layout_height="wrap_content"
         android:layout_width="match_parent">
      <androidx.appcompat.widget.Toolbar
             ...
             app:layout_scrollFlags="scroll|enterAlways"/>
      <com.google.android.material.tabs.TabLayout
             ...
             app:layout_scrollFlags="scroll|enterAlways"/>
      </com.google.android.material.appbar.AppBarLayout>
 </androidx.coordinatorlayout.widget.CoordinatorLayout>