Android自动提示控件AutoCompleteTextView

<autocompletetextview 
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:id="@+id/autotext"
  />

public class mainactivity extends activity {
private autocompletetextview autotext;
private arrayadapter<string> arrayadapter;
  @override
  protected void oncreate(bundle savedinstancestate) {
    super.oncreate(savedinstancestate);
    setcontentview(r.layout.test);

    autotext =(autocompletetextview) findviewbyid(r.id.autotext);
    string [] arr={"aa","aab","aac"};
    arrayadapter = new arrayadapter<string>(this, android.r.layout.simple_list_item_1,arr);
    autotext.setadapter(arrayadapter);
  }

}