如何写菜单

package com.example.menuDemo;

import android.app.Activity;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ContextMenu.ContextMenuInfo;
import android.widget.Toast;

public class MainActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}

// 这个方法给menu文件打气为菜单界面
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}

// 当menu菜单打开时的操作
@Override
public boolean onMenuOpened(int featureId, Menu menu) {
Toast.makeText(getApplicationContext(), "菜单要打开了", 0).show();
return super.onMenuOpened(featureId, menu);
}

// 当点击某个菜单时，要做的操作
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.action_settings1) {
Toast.makeText(getApplicationContext(), "你点击了菜单一", 0).show();
return true;
}
if (id == R.id.action_settings2) {
Toast.makeText(getApplicationContext(), "你点击了菜单二", 0).show();
return true;
}
return super.onOptionsItemSelected(item);
}

//  当选项菜单关闭时调用的方法
@Override
public void onOptionsMenuClosed(Menu menu) {
Toast.makeText(getApplicationContext(), "菜单要关闭了", 0).show();
super.onOptionsMenuClosed(menu);
}
}

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.example.menuDemo.MainActivity" >

<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/hello_world" />

</RelativeLayout>

<menu xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
tools:context="com.example.menuDemo.MainActivity" >

<item
android:id="@+id/action_settings1"
android:orderInCategory="100"
android:showAsAction="never"
android:title="菜单一"/>
<item
android:id="@+id/action_settings2"
android:orderInCategory="100"
android:showAsAction="never"
android:title="菜单二"/>

</menu>