Android TableRow stretch vertically to fill screen

I'm trying to create a phone diale开发者_C百科r view, using a TableLayout to create the 12 buttons in a 3x4 grid. I would like the rows to stretch vertically to use up all available space equally, but it appears fill_parent doesn't work on TableRows.

I would like not to have to use setMinimumHeight - is there a way to do this properly in the layout?

Thanks very much,

Ed

<?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"
>
<TableLayout
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:stretchColumns="*"
    >
    <TableRow 
        android:layout_weight="1"
        android:gravity="center">
        <Button android:text="Button" android:layout_width="fill_parent" android:layout_height="fill_parent"/>
        <Button android:text="Button" android:layout_width="fill_parent" android:layout_height="fill_parent"/>
        <Button android:text="Button" android:layout_width="fill_parent" android:layout_height="fill_parent"/>
    </TableRow>
    <TableRow 
        android:layout_weight="1"
        android:gravity="center">
        <Button android:text="Button" android:layout_width="fill_parent" android:layout_height="fill_parent"/>
        <Button android:text="Button" android:layout_width="fill_parent" android:layout_height="fill_parent"/>
        <Button android:text="Button" android:layout_width="fill_parent" android:layout_height="fill_parent"/>
    </TableRow>
    <TableRow 
        android:layout_weight="1"
        android:gravity="center">
        <Button android:text="Button" android:layout_width="fill_parent" android:layout_height="fill_parent"/>
        <Button android:text="Button" android:layout_width="fill_parent" android:layout_height="fill_parent"/>
        <Button android:text="Button" android:layout_width="fill_parent" android:layout_height="fill_parent"/>
    </TableRow>
    <TableRow 
        android:layout_weight="1"
        android:gravity="center">
        <Button android:text="Button" android:layout_width="fill_parent" android:layout_height="fill_parent"/>
        <Button android:text="Button" android:layout_width="fill_parent" android:layout_height="fill_parent"/>
        <Button android:text="Button" android:layout_width="fill_parent" android:layout_height="fill_parent"/>
    </TableRow>
</TableLayout>
</LinearLayout>