Android之菜单一——选项菜单

Android平台下所提供的菜单大体上可分为三类：选项菜单、上下文菜单和子菜单。

当Activity在前台运行时，如果用户按下手机上的Menu键，此时就会在屏幕低端弹出相应的选项菜单。但这个功能需要开发人员编程来实现的，如果在开发应用程序时没有实现该功能，那么程序运行时按下手机的meun键是不会起作用的。

对于携带图标的选项菜单，每次最多只能显示6个，当菜单选项多于6个时，将只显示前5个和一个扩展菜单选项，点击扩展菜单选项将会弹出其余的菜单项。扩展菜单项中将不会显示图标，但是可以显示单选按钮和复选框。

以下模拟选项菜单

main.xml布局文件

xml version = " 1.0 " encoding = " utf-8 " ?>
< LinearLayout android:id = " @+id/LinearLayout01 "
android:layout_width = " fill_parent "
android:layout_height = " fill_parent "
android:orientation = " vertical "
xmlns:android = " http://schemas.android.com/apk/res/android " >
< ScrollView android:id = " @+id/scrollView "
android:layout_width = " fill_parent "
android:layout_height = " fill_parent " >
< EditText android:id = " @+id/editText "
android:layout_width = " fill_parent "
android:layout_height = " fill_parent "
android:editable = " false "
android:cursorVisible = " false "
android:text = " 您的选择为\n " >
EditText >
ScrollView >
LinearLayout >

MeunActivity类

package com.ljq.activity;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.SubMenu;
import android.view.MenuItem.OnMenuItemClickListener;
import android.widget.EditText;

public class MeunActivity extends Activity {
private final int MENU_GENDER_MALE = 0 ;
private final int MENU_GENDER_FEMALE = 1 ;
private final int MENU_HOBBY1 = 2 ;
private final int MENU_HOBBY2 = 3 ;
private final int MENU_HOBBY3 = 4 ;

private final int MENU_OK = 5 ;

private final int MENU_GENDER = 6 ;
private final int MENU_HOBBY = 7 ;

private final int GENDER_GROUP = 0 ;
private final int HOBBY_GROUP = 1 ;
private final int MAIN_GROUP = 2 ;

MenuItem[] hoddyMenuItems = new MenuItem[ 3 ]; // 爱好菜单项组
MenuItem maleMenuItem = null ; // 男性菜单项

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

/** j
* 初始化选项菜单
*/
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// 单选菜单选项
SubMenu genderMenu = menu.addSubMenu(MAIN_GROUP, MENU_GENDER, 0 , " 性别 " );
genderMenu.setIcon(R.drawable.gender);
genderMenu.setHeaderIcon(R.drawable.gender);
maleMenuItem = genderMenu.add(GENDER_GROUP, MENU_GENDER_MALE, 0 , " 男 " );
maleMenuItem.setChecked( true );
genderMenu.add(GENDER_GROUP, MENU_GENDER_FEMALE, 0 , " 女 " );
// 设置菜单项为单选菜单项，互斥的
genderMenu.setGroupCheckable(GENDER_GROUP, true , true );

// 复选菜单选项
SubMenu hobbyMenu = menu.addSubMenu(MAIN_GROUP,MENU_HOBBY, 0 , " 爱好 " );
hobbyMenu.setIcon(R.drawable.hobby);
hobbyMenu.setHeaderIcon(R.drawable.hobby);
hoddyMenuItems[ 0 ] = hobbyMenu.add(HOBBY_GROUP, MENU_HOBBY1, 0 , " 游泳 " );
hoddyMenuItems[ 1 ] = hobbyMenu.add(HOBBY_GROUP, MENU_HOBBY2, 0 , " 唱歌 " );
hoddyMenuItems[ 2 ] = hobbyMenu.add(HOBBY_GROUP, MENU_HOBBY3, 0 , " 编程 " );
// 设置菜单项为复选菜单项
hoddyMenuItems[ 0 ].setCheckable( true );
hoddyMenuItems[ 1 ].setCheckable( true );
hoddyMenuItems[ 2 ].setCheckable( true );

// 确定菜单项
MenuItem ok = menu.add(MAIN_GROUP,MENU_OK, 0 , " 确定 " );
ok.setOnMenuItemClickListener( new OnMenuItemClickListener(){
public boolean onMenuItemClick(MenuItem item) {
appendStateStr();
return true ;
}
});
// 给确定菜单项添加快捷键
ok.setAlphabeticShortcut( ' o ' ); // 设置字符快捷键
// ok.setNumericShortcut('1'); // 设置数字快捷键
// ok.setShortcut('a', '2'); // 同时设置两种快捷键。注意：同时设置多次时只有最后一个设置起作用
return true ; // 记得返回true，否则无效
}

/**
* 在菜单选项中某个选项被选中时调用该事件
*/
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case MENU_GENDER_MALE:
case MENU_GENDER_FEMALE:
item.setChecked( true );
appendStateStr();
break ;
case MENU_HOBBY1:
case MENU_HOBBY2:
case MENU_HOBBY3:
item.setChecked( ! item.isChecked());
appendStateStr();
break ;
}
return true ;
}

public void appendStateStr() {
String result = " 您选择的性别为： " ;
if (maleMenuItem.isChecked()) {
result = result + " 男 " ;
} else {
result = result + " 女 " ;
}


String hobbyStr = "" ;
for (MenuItem hoddy : hoddyMenuItems) {
if (hoddy.isChecked()) {
hobbyStr = hobbyStr + hoddy.getTitle() + " 、 " ;
}
}
if (hobbyStr.length() > 0 ) {
result = result + " ,您的爱好为： "
+ hobbyStr.substring( 0 , hobbyStr.length() - 1 ) + " 。\n " ;
} else {
result = result + " 。\n " ;
}
EditText et = (EditText) MeunActivity. this .findViewById(R.id.editText);
et.append(result);
}
}

运行结果

1、2、

3、4、