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：

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>