android ListActivity如何创建？

Question

有哪位大神帮忙看看！public class activity2012_10_23_listactivity extends ListActivity {
static final String[] CHOICES=new String[]
{
"WEB","CONTACTS","PHONE DIALER","GOOGLE","VOICE COMMAND"
};
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setListAdapter(new ArrayAdapter<String>(activity2012_10_23_listactivity.this
, android.R.layout.simple_expandable_list_item_1, CHOICES));
}}
想要建一个ListActivity ，这段代码有什么问题吗？为什么老是出错？这是main.xml:
<?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"
android:paddingLeft="8dp"
android:paddingRight="8dp"><ListView android:id="@id/android:list"
android:layout_width="fill_parent" 
android:layout_height="fill_parent"
android:background="#00FF00"
android:layout_weight="1"
android:drawSelectorOnTop="false"/>
</LinearLayout>

Answer 1

在super.onCreate(savedInstanceState);
下面加上
setContentView(R.layout.main);