nested_scrolling.xml

 <ScrollView
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1"
            android:fillViewport="true"
            android:nestedScrollingEnabled="true">

            <android.support.constraint.ConstraintLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content">

                <android.support.v7.widget.RecyclerView    
                    android:id="@+id/recyclerview"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:listSelector="@android:color/transparent"
                    android:nestedScrollingEnabled="true"
                    app:layout_constraintEnd_toEndOf="parent"
                    app:layout_constraintStart_toStartOf="parent"
                    app:layout_constraintTop_toTopOf="parent" />

                <Button
                    android:id="@+id/button"
                    android:layout_width="match_parent"                    
                    android:layout_alignParentBottom="true"
                    android:layout_gravity="center"
                    app:layout_constraintBottom_toBottomOf="parent"
                    app:layout_constraintEnd_toEndOf="parent"
                    app:layout_constraintStart_toStartOf="parent"
                    app:layout_constraintTop_toBottomOf="@+id/recyclerview"
                    app:layout_constraintVertical_bias="1.0" />
            </android.support.constraint.ConstraintLayout>
        </ScrollView>