Androd ListActivity 和Menu整合

package com.turboradio.googlesdk;

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 Ex4_20 extends ListActivity {
    private int selectedItem = -1;
    private String [] mString;
    private ArrayAdapter<String> mla;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        
    }
    /**
     * ListView的列表单机事件
     */
    @Override
    protected void onListItemClick(ListView l, View v, int position, long id) {
        selectedItem = position;
        Toast.makeText(this, mString[selectedItem], Toast.LENGTH_LONG).show();
        super.onListItemClick(l, v, position, id);
    }

    /**生成Menu菜单**/
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        int idGroup1 = 0;
        int orderMenuItem1 = Menu.NONE;
        int orderMenuItem2 = Menu.NONE+1;
        menu.add(idGroup1, orderMenuItem1, 0, "显示列表1");
        menu.add(idGroup1, orderMenuItem2, 1, "显示列表2");
        return super.onCreateOptionsMenu(menu);
    }
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch(item.getItemId()){
        case 0:
            Toast.makeText(Ex4_20.this, "1", Toast.LENGTH_LONG).show();
            mString = new String[]{"张三","李四","王五","赵六"};
            mla = new ArrayAdapter<String>(Ex4_20.this,android.R.layout.simple_list_item_1,mString);
            Ex4_20.this.setListAdapter(mla);
            break;
        case 1:
            Toast.makeText(Ex4_20.this, "2", Toast.LENGTH_LONG).show();
            mString = new String[]{"JAVA","C","C++","PHP","OBJECTIVE-C"};
            mla = new ArrayAdapter<String>(Ex4_20.this,android.R.layout.simple_list_item_1,mString);
            Ex4_20.this.setListAdapter(mla);
            break;
        }
        return super.onOptionsItemSelected(item);
    }
    
}