Scrollview嵌套Recyclverview只显示一行

<RelativeLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:descendantFocusability="blocksDescendants">
<android.support.v7.widget.RecyclerView
    android:id="@+id/playdate_recyclerview"
    android:divider="@color/vr_gray"
    android:dividerHeight="1dp"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" />
</RelativeLayout>