问TextView垂直居中在RelativeLayout中不起作用

EN

<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#FFFFFF"
android:focusable="true"
android:focusableInTouchMode="true">

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="#FFFFFF"
    android:paddingBottom="4dp"
    android:paddingLeft="16dp"
    android:paddingRight="16dp"
    android:paddingTop="8dp">

    <TextView
        android:id="@+id/tvCheckStockStatus"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:layout_alignParentTop="true"
        android:layout_marginBottom="6dp"
        android:text="Check Stock Status"
        android:textColor="@color/color_primary"
        android:textSize="15sp" />

    <TextView
        android:id="@+id/tvItemCode"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/tvCheckStockStatus"
        android:layout_marginLeft="3dp"
        android:text="@string/sample_text"
        android:textColor="#000000"
        android:textSize="16sp"
        android:textStyle="bold"
        android:visibility="visible" />

    <EditText
        android:id="@+id/edDescription"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/ivRemark"
        android:layout_below="@+id/tvItemCode"
        android:layout_marginBottom="2dp"
        android:layout_toLeftOf="@+id/ivRemark"
        android:layout_weight="1"
        android:hint="@string/description"
        android:inputType="textCapWords"
        android:selectAllOnFocus="true"
        android:text=""
        android:textSize="17sp" />

    <ImageView
        android:id="@+id/ivRemark"
        android:layout_width="36dp"
        android:layout_height="36dp"
        android:layout_alignParentRight="true"
        android:layout_below="@+id/tvItemCode"
        android:focusableInTouchMode="false"
        android:padding="2dp"
        android:src="@drawable/ic_action_remark"
        android:visibility="visible" />

    <TextView
        android:id="@+id/location"
        android:layout_width="100dp"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_below="@+id/edDescription"
        android:layout_gravity="center_vertical"
        android:layout_weight="30"
        android:paddingRight="5dp"
        android:text="@string/location"
        android:textColor="#555555"
        android:textSize="15sp"
        android:visibility="visible"
        android:gravity="center_vertical|right"
        android:layout_alignWithParentIfMissing="false"
        android:allowUndo="false"
        android:layout_alignBottom="@+id/spLocationBlock" />

    <LinearLayout
        android:id="@+id/spLocationBlock"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="#F5F5F5"
        android:orientation="vertical"
        android:visibility="visible"
        android:layout_alignParentRight="true"
        android:layout_toEndOf="@id/location"
        android:layout_below="@+id/edDescription"
        android:measureWithLargestChild="false">

        <widgets.CustomSpinner
            android:id="@+id/spLocation"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginBottom="8dp"
            android:layout_marginLeft="4dp"
            android:layout_marginRight="4dp"
            android:layout_marginTop="8dp"
            android:visibility="visible" />
    </LinearLayout>
 </RelativeLayout>