How do I decrease the space between cards in a CardView within a RecyclerView?

Edit these attributes

card_view:cardMaxElevation="1dp"card_view:cardElevation="1dp"

so full code will be

<?xml version="1.0" encoding="utf-8"?><android.support.v7.widget.CardView    xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:card_view="http://schemas.android.com/apk/res-auto"    android:id="@+id/card_view"    android:layout_width="match_parent"    android:layout_height="200dp"    card_view:cardCornerRadius="5dp"    card_view:cardMaxElevation="1dp"    card_view:cardElevation="1dp"      card_view:cardBackgroundColor="@color/colorPrimary"    card_view:cardUseCompatPadding="true"    card_view:cardPreventCornerOverlap="false"    >    <LinearLayout        android:layout_width="match_parent"        android:layout_height="match_parent"        android:orientation="vertical"        android:id="@+id/card_list">        <ImageView            android:id="@+id/thumbnail"            android:layout_width="match_parent"            android:layout_height="match_parent"            android:layout_gravity="center"            android:gravity="center"            android:src="@drawable/bag"            android:contentDescription="string/video_thumbnail_description"            android:layout_weight="1"            />        <TextView            android:id="@+id/video_title_view"            android:layout_height="match_parent"            android:layout_width="wrap_content"            android:layout_gravity="center"            android:gravity="center"            android:text="lovelksdjslkdjlsdj"            android:layout_weight="3"            />    </LinearLayout></android.support.v7.widget.CardView>

<?xml version="1.0" encoding="utf-8"?><android.support.v7.widget.CardView    android:id="@+id/card_view"    xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="wrap_content"    xmlns:app="http://schemas.android.com/apk/res-auto"    app:cardCornerRadius="4dp"    app:cardElevation="1dp"    app:cardMaxElevation="1dp"    app:cardUseCompatPadding="true" >  //this line is game changer