Write android view center of screen

center_views.xml

<RelativeLayout
	android:layout_width="match_parent"
	android:layout_height="match_parent">
	<TextView
		android:layout_width="wrap_content"
		android:layout_height="wrap_content"
		android:text="@string/app_name"
		android:layout_centerInParent="true"/>
</RelativeLayout>

<!-- ----- -->

<LinearLayout
	android:layout_width="match_parent"
	android:layout_height="match_parent"
	android:orientation="horizontal">
	<LinearLayout
		android:layout_width="match_parent"
		android:layout_height="wrap_content"
		android:layout_gravity="center_vertical"
		android:orientation="vertical">
		<ScrollView
			android:layout_width="match_parent"
			android:layout_height="wrap_content">
			<LinearLayout
				android:layout_width="match_parent"
				android:layout_height="wrap_content"
				android:orientation="vertical">
                    
					<!-- center views -->
					
			</LinearLayout>
		</ScrollView>
	</LinearLayout>
</LinearLayout>