Android: Gap between CardView elements in ListView

Change yout listview some thing like this

 <ListView 
    android:id="@+id/ListView01" 
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:divider="@color/redBackground"
    android:dividerHeight="1dip">// Increase this height as your need
 </ListView>

Do it like this:

<androidx.cardview.widget.CardView
    android:id="@+id/matrix"
    app:cardBackgroundColor="#f6f6f6"
    app:cardCornerRadius="8dp"
    app:cardElevation="2dp"
    android:layout_marginStart="8dp"
    android:layout_marginEnd="8dp"
    android:layout_marginBottom="0.7dp"
    android:layout_marginTop="0.7dp"
    app:cardPreventCornerOverlap="false"
    app:cardUseCompatPadding="true"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

If you increase the cardElevation or marginBottom gap will be increased.