In Android ListActivity, how do you apply layout formatting to footers?

In an Android ListActivity, I am adding a button as a footer in a ListView. How can I apply layout formatting to this button like centering it and/or width=fill_parent?

I have tried a few things such as using setLayoutParams(), but have not gotten it to work - the footer always disappears when I try anything.

Here is the basic code I am working with

closeButton = new Button(this);
closeButton.setText(getResources().getString(R.string.title_closeprocess));
closeButton.setOnClickListener(new OnClickListener(){
        public void onClick(View v) {               
            closeProcess();
        }

   });

getListView().addFooterView(closeButton);   

*update

Based on Christopher's answer, here is the footer view that I am adding to my listview, and the activity code that 开发者_开发技巧adds it to the listview:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/closebutton_layout"    
android:layout_width="fill_parent"
android:layout_height="wrap_content">

<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/toptable" 
    android:layout_width="fill_parent"
    android:stretchColumns="*" 
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true" 
    android:layout_height="wrap_content">
    <TableRow>          
        <Button android:id="@+id/closebutton" 
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" 
        android:text="Skip Question"
        android:gravity="center" 
        android:paddingTop="16dip">
    </Button>           
    </TableRow>         
</TableLayout>
</RelativeLayout>



ListView listView = getListView();

    closeButtonView = getLayoutInflater().inflate(R.layout.closebutton_layout, listView, false);
    closeButton = (Button)closeButtonView.findViewById(R.id.closebutton);       
    closeButton.setOnClickListener(new OnClickListener(){
        public void onClick(View v) {
            closeQuestion();                
        }

    });
listView.addFooterView(closeButtonView);

Does it have to be a footer and scroll with the list? Otherwise you could just add it to the bottom in your XML layout, e.g.:

<LinearLayout
    android:orientation="vertical"
    android:weightSum="1">
  <ListView
      android:id="@id/android:list"
      android:layout_width="fill_parent"
      android:layout_weight="1" />
  <Button
      android:id="@+id/btn_close"
      ... />
</LinearLayout>

Alternatively, does placing your Button inside a LinearLayout, then adding that as a footer help?

Edit:
My brain really wasn't switched on earlier.

You can define the footer in a separate layout XML file, then inflate that and add it as your footer as normal. e.g.:

ListView lv = getListView();
View footer = getLayoutInflater().inflate(R.layout.list_footer, lv, false);
lv.addFooterView(footer);