Center textview, when other textview it's null (or dont have text)

I followed this tutorial, for now it's working nice, but i only have a problem, i need to center vertically the "Title" textview, when "Detail" textview开发者_如何转开发 text it's null or empty, something like this, any help appreciated, thanks

Here it's the custom_layout.xml

    <?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <ListView
    android:id="@+id/list"
    android:layout_width="1px"
    android:layout_height="1px"
    android:layout_weight="1">
    </ListView>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <ImageView
    android:id="@+id/img"
    android:layout_width="50dp"
    android:layout_height="60dp"/>
    <RelativeLayout  xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="?android:attr/listPreferredItemHeight"
    android:padding="6dip">
    <TextView
    android:id="@+id/detail"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_toRightOf="@id/img"
    android:layout_alignParentBottom="true"
    android:layout_alignParentRight="true"
    android:singleLine="true"
    android:ellipsize="marquee" />
    <TextView
    android:id="@+id/title"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_toRightOf="@id/img"
    android:layout_alignParentRight="true"
    android:layout_alignParentTop="true"
    android:layout_above="@id/detail"
    android:layout_alignWithParentIfMissing="true"
    android:gravity="center_vertical"
    android:textColor="#ffffffff"
    android:textSize="24sp" />
    </RelativeLayout>
    </LinearLayout>
    </LinearLayout>

You use android:layout_gravity to center the actual text view and android:gravity to center the things inside the text view (like the text).

Example XML:

<TextView android:id="@+id/some_id"
          android:text="Example text"
          android:layout_height="70dp"
          android:layout_width="wrap_content"
          android:gravity="center_vertical" />