Set equal width of columns in table layout in Android

Possible Duplicate:
XML Table layout? Two EQUAL-width rows filled with equally width buttons?

I am using TableLayout to show list of data in 4 columns.

Problem description:

I am unable to set equal width of all 4 columns, which are in my TableLayout. I am putting my layout code, which I am using...

<TableLayout android:layout_width="fill_parent" android:layout_height="wrap_content" android:stretchColumns="0">
        <TableRow>
            <TextView android:text="table header1" android:layout_width="wrap_content" android:layout_height="wrap_content" 
                 android:textSize="10dip" android:textStyle="bold"/>    
            <TextView android:text="table header2" android:layout_width="wrap_content" android:layout_height="wrap_content" 
                android:textSize="10dip" android:textStyle="bold"/> 
            <TextView android:text="table header3" android:layout_width="wrap_content" android:layout_height="wrap_content" 
                android:textSize="10dip" android:textStyle="bold"/> 
            <TextView android:text="table header4" android:layout_width="wrap_content" android:layout_height="wrap_content" 
                android:textSize="10dip" android:textStyle="bold"/>         
        </TableRow>
    </TableLayout>

How should I rewrite this layout to show 4 columns with equal sizes?