Align two TextViews, one left the other right, on a ListView without stretching the backgrounds

So I've got two TextViews per row in a ListView. One should be left and the other right aligned. Both TextViews have a rounded rectangle as background which should just wrap the text inside. So I came up with this:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" >

    <TextView
        android:id="@+id/text_right"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:background="@drawable/bubble_purple"
        android:gravity="center" >
    </TextView>

    <TextView
        android:id="@+id/text_left"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_toLeftOf="@id/text_right"
        android:background="@drawable/bubble_blue"
        android:gravity="center" >
    </TextView>
</RelativeLayout>

It looks good for long texts but not for shorter messages:

I also tried a LinearLayout like this:

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

    <TextView
        android:id="@+id/text_left"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="0"
        android:background="@drawable/bubble_blue"
        android:gravity="center" >
    </TextView>

    <View
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:layout_weight="1" />

    <TextView
        android:id="@+id/text_right"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="0"
        android:background="@drawable/bubble_purple"
        android:gravity="center">
    </TextView>
</LinearLayout>

This works for short messages but not for longer ones:

Is it somehow possible to measure the combined width of the TextViews and programmatically switch between these layouts, or am I doing something wrong here?