比如可以这样写代码，CardView就变成普通的FrameLayout：

<?xml version="1.0" encoding="utf-8"?> 
<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    xmlns:card_view="http://schemas.android.com/apk/res-auto" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:background="?attr/selectableItemBackground" 
    app:cardCornerRadius="0dp" 
    app:cardElevation="0dp" 
    app:cardPreventCornerOverlap="true" 
    app:cardUseCompatPadding="true" 
    card_view:contentPadding="0dp"> 
 
    
</android.support.v7.widget.CardView>