I have a complex layout, part of which features a value centered over a label, with + and - buttons on either side of the value. I want the value to center between the buttons, whether it is "1" or "99". It looks fine when it's a 2-digit number like "99", but when it's a single digit the number is left-justified. How do I properly center that value?

Here's the portion of my layout that does this:

```
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_above="@id/runway_label"
    android:layout_centerHorizontal="true"
    android:orientation="horizontal">

    <ImageView
        android:id="@+id/dec_runway_button"
        android:src="@drawable/minus_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_vertical"/>

    <TextView
        android:id="@+id/runway_value"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textColor="#FFFFFF"
        android:textStyle="bold"
        android:textSize="40.0sp"
        android:minWidth="50sp"
        android:layout_centerInParent="true"
        android:layout_gravity="center"
        android:shadowColor="#333333"
        android:shadowDx="2.0"
        android:shadowDy="2.0"
        android:shadowRadius="3.0" />

    <ImageView
        android:id="@+id/inc_runway_button"
        android:src="@drawable/plus_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_vertical"/>

</LinearLayout>

```