android relativelayout height not working corretly

Question

I want android:text="30" textview be center position in Relativelayout.

but android:layout_height="match_parent" is not working correctly. It look like "wrap_content".

I was trying everything I found adding one more Relativelayout and do working correctly.

1. how text"30" move center position
2. why match_parent not work?

3. why added one more Relativelayout then working correctly?

   <androidx.core.widget.NestedScrollView
       android:id="@+id/product_grid"
       android:layout_width="match_parent"
       android:layout_height="match_parent"
       android:layout_marginTop="56dp"
       android:background="@color/productGridBackgroundColor"
       android:elevation="8dp"
       app:layout_behavior="@string/appbar_scrolling_view_behavior">
   
       <LinearLayout
           android:layout_width="match_parent"
           android:layout_height="wrap_content"
           android:clipChildren="false"
           android:clipToPadding="false"
           android:orientation="vertical"
           android:padding="24dp"
           android:paddingTop="16dp">
   
           <com.google.android.material.card.MaterialCardView
               style="@style/Widget.MaterialComponents.CardView"
               android:layout_height="wrap_content"
               android:layout_width="match_parent"
               android:layout_marginLeft="@dimen/mtrl_card_spacing"
               android:layout_marginTop="@dimen/mtrl_card_spacing"
               android:layout_marginRight="@dimen/mtrl_card_spacing"
               android:minHeight="200dp">
   
               **<!--height = match_parent not working-->**
               <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/home_card_title_level"/>
   
                   <TextView
                       android:layout_width="wrap_content"
                       android:layout_height="wrap_content"
   
                       android:layout_centerHorizontal="true"
                       android:layout_centerVertical="true"
                       android:text="30"/>
   
               </RelativeLayout>
   
               <!--**if this code added then work perfectly**
               <RelativeLayout
                   android:layout_width="match_parent"
                   android:layout_height="match_parent"/>
               -->
   
           </com.google.android.material.card.MaterialCardView>
   
       </LinearLayout>
   </androidx.core.widget.NestedScrollView>
   

Answer 1

Remove Relative Layout and add android:layout_gravity="center

  <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_gravity="center"
                android:layout_centerHorizontal="true"
                android:layout_centerVertical="true"
                android:text="30"/>