Android 菜单(ContextMenu)
Android 的ContextMenu，即上下文菜单。（类似电脑上的鼠标右键功能，选中某个元素，然后点右键，在弹出菜单上执行操作。）在手机上，通过长时间按住界面上的元素，就会出现事先设计好的上下文菜单。
主要用到的方法有：
// 创建显示上下文菜单
setOnCreateContextMenuListener
//监听长按事件
setOnItemLongClickListener
//监听普通按键事件
setOnItemClickListener
//上下文菜单的选中事件
onContextItemSelected
//监听上下文菜单关闭事件
onContextMenuClosed
示例（ListView上下文菜单）
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效果图
main_list_view.xml 配置
<?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="fill_parent"
>
<ListView
android:id="@+id/main_list_view_listview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
/>
</LinearLayout>
main_list_view_item.xml配置
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/RelativeLayout_Item"
android:layout_width="fill_parent" android:layout_height="wrap_content"
android:paddingBottom="5dip"
>
<TextView
android:id="@+id/main_list_view_item_item_text"
android:layout_centerHorizontal="true"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="20px"
android:layout_gravity="center"
/>
</LinearLayout>
Activity代码
package com.zhouzijing.android;
import java.util.ArrayList;
import com.zhouzijing.android.util.MenuEntity;
import com.zhouzijing.android.util.SimpleAdapterUtil;
import android.app.Activity;
import android.content.Context;
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.view.View.OnCreateContextMenuListener;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemLongClickListener;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.Toast;
import android.widget.AdapterView.OnItemClickListener;
public class Menu2 extends Activity {
final Context context = this;
//定义1个ListView
private ListView listView = null;
//定义ListView需要显示的数据
private ArrayList<ArrayList<Object>> viewInfos = null;
//定义上下文菜单
final private static int CONTEXT_MENU_EDIT = 0;//菜单[编辑]的编号
final private static int CONTEXT_MENU_SHARE = 1;//菜单[分享]的编号
final private static int CONTEXT_MENU_DELETE = 2;//菜单[删除]的编号
final private static int CONTEXT_MENU_CANCEL = 3;//菜单[取消]的编号
private int itemLongClickSelected = 0;
private MenuEntity[] contextMenus = {
new MenuEntity(0, CONTEXT_MENU_EDIT, 0, "编辑"),
new MenuEntity(0, CONTEXT_MENU_SHARE, 1, "分享"),
new MenuEntity(0, CONTEXT_MENU_DELETE, 2, "删除"),
new MenuEntity(0, CONTEXT_MENU_CANCEL, 3, "取消"),
};
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_list_view);
//初始化要显示的内容
initListViewInfos();
//显示ListView
showListView();
//显示ListView的上下文菜单
showListViewContextMenu();
}
/**
* 初始化ListView需要显示的内容.
*/
public void initListViewInfos(){
viewInfos = new ArrayList<ArrayList<Object>>();
ArrayList<Object> countrys = new ArrayList<Object>();
countrys.add("Austria");
countrys.add("China");
countrys.add("Egypt");
countrys.add("France");
countrys.add("Ireland");
countrys.add("Japan");
countrys.add("Spain");
countrys.add("United Kingdom");
countrys.add("United States");
viewInfos.add(countrys);
}
/**
* 从ListView显示内容中删除1条记录.
*/
public void removeItem(int index){
viewInfos.get(0).remove(index);
}
/**
* 从ListView显示内容中读取1条记录
* @param index
* @return
*/
public Object readItem(int index){
return viewInfos.get(0).get(index);
}
/**
* 读取当前执行的菜单
* @param index
* @return
*/
public CharSequence readContextMenu(int index){
for(int i=0;i<contextMenus.length;i++){
if(contextMenus[i].getItemId()==index) return contextMenus[i].getTitle();
}
return "";
}
/**
* 显示ListView.
*/
public void showListView(){
final Context context = this;
//定义适配器to参数
int[] to = {R.id.main_list_view_item_item_text};
int resource = R.layout.main_list_view_item;
//生成适配器:使用自定义工具类 SimpleAdapterUtil.java来生成适配器
SimpleAdapter simpleAdapter = SimpleAdapterUtil.create(context,viewInfos,resource,to);
listView = (ListView)findViewById(R.id.main_list_view_listview);
listView.setAdapter(simpleAdapter);
}
/**
* 显示ListView的上下文菜单
*/
public void showListViewContextMenu(){
//创建上下文菜单
listView.setOnCreateContextMenuListener(new OnCreateContextMenuListener(){
@Override
public void onCreateContextMenu(ContextMenu menu, View v,
ContextMenuInfo menuInfo) {
menu.setHeaderTitle(readItem(itemLongClickSelected).toString());
MenuEntity menuEntity = null;
for(int i=0;i<contextMenus.length;i++){
menuEntity = contextMenus[i];
menu.add(menuEntity.getGroupId(),menuEntity.getItemId(),menuEntity.getOrder(),menuEntity.getTitle());
}
}
});
//监听列表项目的长按事件
listView.setOnItemLongClickListener(new OnItemLongClickListener(){
@Override
public boolean onItemLongClick(AdapterView<?> parent, View view,
int position, long id) {
itemLongClickSelected = position;
Toast.makeText(context,"item["+position+":"+readItem(itemLongClickSelected).toString()+"]被长时间点击了.",Toast.LENGTH_SHORT).show();
return false;
}
});
//监听列表项目的普通点击事件
listView.setOnItemClickListener(new OnItemClickListener(){
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
Toast.makeText(context,"item["+position+":"+readItem(position).toString()+"]被点击了.",Toast.LENGTH_SHORT).show();
}
});
}
@Override
public boolean onContextItemSelected(MenuItem item) {//执行上下文菜单中的菜单
int itemId = item.getItemId();
Toast.makeText(context,"Context menu item["+itemId+":"+readContextMenu(itemId)+"] is Selected.",Toast.LENGTH_SHORT).show();
if(CONTEXT_MENU_DELETE==itemId){//删除
//当前选中的ListView中的item编号
int index = itemLongClickSelected;
//在当前ListView中删除选中的元素
removeItem(index);
//重新显示ListView
showListView();
}
return super.onContextItemSelected(item);
}
@Override
public void onContextMenuClosed(Menu menu) {//关闭上下文菜单
Toast.makeText(context,"Context Menu is Closed.",Toast.LENGTH_SHORT).show();
super.onContextMenuClosed(menu);
}
}
备注：
private MenuEntity[] contextMenus = {
new MenuEntity(0, CONTEXT_MENU_EDIT, 0, "编辑"),
new MenuEntity(0, CONTEXT_MENU_SHARE, 1, "分享"),
new MenuEntity(0, CONTEXT_MENU_DELETE, 2, "删除"),
new MenuEntity(0, CONTEXT_MENU_CANCEL, 3, "取消"),
};
参考 关于菜单基础属性的实体类
SimpleAdapter simpleAdapter = SimpleAdapterUtil.create(context,viewInfos,resource,to);
参考 1个简单的SimpleAdapter工具类-SimpleAdapterUtil（版本二：数据格式为ArrayList<ArrayList<Object>>）
关于根据上下文菜单来获取当前选中的GridView(或ListView等)的元素
//OnCreateContextMenuListener
gridPhoneBook.setOnCreateContextMenuListener(new OnCreateContextMenuListener(){
@Override
public void onCreateContextMenu(ContextMenu menu, View v,
ContextMenuInfo menuInfo) {
//获取上下文菜单点击的GridView中的元素
AdapterContextMenuInfo info = (AdapterContextMenuInfo) menuInfo;
int position = info.position;
//设置上下文菜单的标题
PhoneBook phoneBook = (PhoneBook)phoneBookAdapter.getItem(position);
menu.setHeaderTitle(phoneBook.getName());
//设置上下文菜单
MenuEntity menuEntity;
for(int i=0;i<CONTEXT_MENUS.length;i++){
menuEntity = CONTEXT_MENUS[i];
menu.add(menuEntity.getGroupId(), menuEntity.getItemId()
,menuEntity.getOrder(),menuEntity.getTitle());
}
}
});
/**
* 上下文菜单-具体菜单的执行操作.
*/
@Override
public boolean onContextItemSelected(MenuItem item) {
//获取选中的GridView的元素
AdapterContextMenuInfo info = (AdapterContextMenuInfo)item.getMenuInfo();
int position = info.position;
PhoneBook phoneBook = (PhoneBook)phoneBookAdapter.getItem(position);
//菜单ID
int menuId = item.getItemId();
switch(menuId){
case CONTEXT_MENU_PHONE_BOOK_DELETE:
doContextMenuOfDelete(phoneBook);
break;
}
return super.onContextItemSelected(item);
}
