android中Menu介绍

大家都知道，任务程序离不开菜单，菜单无处不在，哪我们一定要学好ANDROID中的菜单，它给我带来了不少的功能。相信大家都知道的。好，现在我们开始吧，下面的代码很简单。看图：

package com.smart;  
 
import android.app.Activity;  
import android.os.Bundle;  
import android.view.Menu;  
import android.view.MenuItem;  
import android.view.View;  
import android.widget.Button;  
 
public class SmartMenu extends Activity {  
 public static final int ITEM0=Menu.FIRST;//系统值  
 public static final int ITEM1=Menu.FIRST+1;  
 public static final int ITEM2=Menu.FIRST+2;  
 public static final int ITEM3=Menu.FIRST+3;  
 Button button1;  
 Button button2;  
 Button button3;  
 Button button4;  
// private Menu menu;  
// private Menu menu  
   
 
 /** Called when the activity is first created. */ 
    @Override 
    public void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.main);  
        button1=(Button)findViewById(R.id.button1);  
        button2=(Button)findViewById(R.id.button2);  
        button3=(Button)findViewById(R.id.button3);  
        button4=(Button)findViewById(R.id.button4);  
        button1.setVisibility(View.INVISIBLE);  
        button2.setVisibility(View.INVISIBLE);  
        button3.setVisibility(View.INVISIBLE);  
        button4.setVisibility(View.INVISIBLE);  
//          
    }  
      
      
    @Override 
 public boolean onCreateOptionsMenu(Menu menu) {  
  super.onCreateOptionsMenu(menu);  
  menu.add(0, ITEM0, 0,"显示button1");  
  menu.add(0, ITEM1,0,"显示button2");  
  menu.add(0, ITEM2,0,"新建");  
  menu.add(0, ITEM3,0,"打开");  
  menu.findItem(ITEM1);//可以设置按钮的背景  
  return true;  
 }  
 
 
 @Override 
 public boolean onOptionsItemSelected(MenuItem item) {  
    
  switch (item.getItemId()) {  
  case ITEM0:  
   actionClickMenuItem1();  
   break;  
  case ITEM1:  
   actionClickMenuItem2();  
   break;  
  case ITEM2:  
   actionClickMenuItem3();  
   break;  
  case ITEM3:  
   actionClickMenuItem4();  
   break;  
  }  
    
  return super.onOptionsItemSelected(item);  
 }  
   
 //第一个事件的方法  
   
   private void actionClickMenuItem1(){  
    setTitle("button1可见");  
    button1.setVisibility(View.VISIBLE);//可见  
    button2.setVisibility(View.INVISIBLE);//不可见  
      
   }  
   //第2个事件的方法  
   private void actionClickMenuItem2(){  
    setTitle("button2可见");  
    button1.setVisibility(View.INVISIBLE);//不可见  
    button2.setVisibility(View.VISIBLE);//可见  
      
   }  
   private void actionClickMenuItem3(){  
    setTitle("button2可见");  
    button1.setVisibility(View.INVISIBLE);//不可见  
    button2.setVisibility(View.INVISIBLE);//不可见  
    button3.setVisibility(View.VISIBLE);//可见  
    button4.setVisibility(View.INVISIBLE);//不可见  
     
      
      
  }  
     
   private void actionClickMenuItem4(){  
    setTitle("button2可见");  
    button1.setVisibility(View.INVISIBLE);//不可见  
    button2.setVisibility(View.INVISIBLE);//不可见  
    button3.setVisibility(View.INVISIBLE);//不可见  
    button4.setVisibility(View.VISIBLE);//可见  
      
   }  
      
}

<?xml version="1.0" encoding="utf-8"?>  
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:orientation="vertical" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    >  
      
    <Button  
    android:id="@+id/button1" 
     android:layout_width="fill_parent"   
    android:layout_height="wrap_content"   
    android:text="我的菜单我做主_1" 
    />  
      
      <Button  
    android:id="@+id/button2" 
     android:layout_width="fill_parent"   
    android:layout_height="wrap_content"   
    android:text="我的菜单我做主_2" 
    />  
      
     <Button  
    android:id="@+id/button3" 
     android:layout_width="fill_parent"   
    android:layout_height="wrap_content"   
    android:text="小子，给记住这代码" 
    />  
      
      <Button  
    android:id="@+id/button4" 
    android:layout_width="fill_parent"   
    android:layout_height="wrap_content"   
    android:text="哈哈，你欺负我呀，我就能记住" 
    />  

</LinearLayout>