Android：控件AutoCompleteTextView 自动提示

<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);
}

}