Android中ListActivity用法实例分析

import android.app.ListActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;
public class A08Activity extends ListActivity {
 private int selectedItem=-1;
 private ArrayAdapter<String> aa;
 private String[] s;
 private static final int MENU_LIST01=Menu.FIRST;
 private static final int MENU_LIST02=Menu.FIRST+1;
  /** Called when the activity is first created. */
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    //setContentView(R.layout.main);
  }
  protected void onListItemClick(ListView l,View v,int position,long id){
   selectedItem=position;
   Toast.makeText(A08Activity.this, s[selectedItem], Toast.LENGTH_LONG).show();
   super.onListItemClick(l, v, position, id);
  }
  public boolean onCreateOptionsMenu(Menu menu){
   int idGroup1=0;
   int orderMenuItem01=Menu.NONE;
   int orderMenuItem02=Menu.NONE+1;
   menu.add(idGroup1, MENU_LIST01, orderMenuItem01, R.string.str_menu_list01);
   menu.add(idGroup1, MENU_LIST02, orderMenuItem02, R.string.str_menu_list02);
 return super.onCreateOptionsMenu(menu);
  }
  public boolean onOptionsItemSelected(MenuItem item){
   switch(item.getItemId()){
   case MENU_LIST01:
   s=new String[]{
    getResources().getString(R.string.str_list01),
    getResources().getString(R.string.str_list02),
    getResources().getString(R.string.str_list03),
    getResources().getString(R.string.str_list04)
       };
   aa=new ArrayAdapter<String>(A08Activity.this,R.layout.main,s);
   A08Activity.this.setListAdapter(aa);
   break;
   case MENU_LIST02:
   s=new String[]{
    getResources().getString(R.string.str_list05),
    getResources().getString(R.string.str_list06),
    getResources().getString(R.string.str_list07),
    getResources().getString(R.string.str_list08)
       };
   aa=new ArrayAdapter<String>(A08Activity.this,R.layout.main,s);
   A08Activity.this.setListAdapter(aa);
   break;
   }   
 return super.onOptionsItemSelected(item);
  }
}

<?xml version="1.0" encoding="utf-8"?>
<TextView
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:id="@+id/myTextView1"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  android:text="@string/hello"
/>