问Android cardview第一项和最后一项显示不正确

EN

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">


    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:padding="8dp"
        tools:context=".MainActivity">

        <android.support.v7.widget.RecyclerView
            android:id="@+id/recycler_view"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:scrollbars="vertical" />
        <TextView
            android:id="@+id/empty_view"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:drawableTop="@drawable/tryagain"
            android:gravity="center"
            android:visibility="gone"
            android:text="@string/no_data_available" />
    </RelativeLayout>

</LinearLayout>