Android开发之菜单(menu)用法实例分析

<menu xmlns:android="http://schemas.android.com/apk/res/android">
 <item android:id="@+id/about"
   android:title="关于" />
 <item android:id="@+id/exit"
   android:title="退出" />
</menu>

package com.yarin.android.Examples_04_13;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
public class Activity01 extends Activity
{
 /** Called when the activity is first created. */
 @Override
 public void onCreate(Bundle savedInstanceState)
 {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.main);
 }
 /*创建menu*/
 public boolean onCreateOptionsMenu(Menu menu)
 {
  //MenuInflater class is used to instantiate menu XML files into Menu objects
  MenuInflater inflater = getMenuInflater();
  //设置menu界面为res/menu/menu.xml
  inflater.inflate(R.menu.menu, menu);
  return true;
 }
 /*处理菜单事件*/
 public boolean onOptionsItemSelected(MenuItem item)
 {
  //得到当前选中的MenuItem的ID,
  int item_id = item.getItemId();
  switch (item_id)
  {
   case R.id.about:
    /* 新建一个Intent对象 */
    Intent intent = new Intent();
    /* 指定intent要启动的类 */
    intent.setClass(Activity01.this, Activity02.class);
    /* 启动一个新的Activity */
    startActivity(intent);
    /* 关闭当前的Activity */
    Activity01.this.finish();
    break;
   case R.id.exit:
    Activity01.this.finish();
    break;
  }
  return true;
 }
}

package com.yarin.android.Examples_04_13;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
public class Activity02 extends Activity
{
 public void onCreate(Bundle savedInstanceState)
 {
  super.onCreate(savedInstanceState);
  /* 设置显示main2.xml布局 */
  setContentView(R.layout.main2);
 }
 /*创建menu*/
 public boolean onCreateOptionsMenu(Menu menu)
 {
  //为menu添加内容
  menu.add(0, 0, 0, R.string.ok);
  menu.add(0, 1, 1, R.string.back);
  return true;
 }
 /*处理menu的事件*/
 public boolean onOptionsItemSelected(MenuItem item)
 {
  //得到当前选中的MenuItem的ID,
  int item_id = item.getItemId();
  switch (item_id)
  {
   case 0:
   case 1:
    /* 新建一个Intent对象 */
    Intent intent = new Intent();
    /* 指定intent要启动的类 */
    intent.setClass(Activity02.this, Activity01.class);
    /* 启动一个新的Activity */
    startActivity(intent);
    /* 关闭当前的Activity */
    Activity02.this.finish();
    break;
  }
  return true;
 }
}