android开发步步为营之27：上下文菜单ContextMenu的用法

ContextMenu上下文菜单，它是通过长时间的按住一个view弹出来的菜单，比如长时间按住一个图片、文本等，都可以触发弹出一个上下文菜单。可以根据选择的菜单，弹出相应的消息或者跳转到相关的Activity中去。
public interface ContextMenu implements Menu
 
android.view.ContextMenu
 
Class Overview
Extension of Menu for context menus providing functionality to modify the header of the context menu.
 
Context menus do not support item shortcuts and item icons.
 
To show a context menu on long click, most clients will want to call registerForContextMenu(View) and override onCreateContextMenu(ContextMenu, View, ContextMenu.ContextMenuInfo).
     开始我们的实验。
第一步、设计页面contextmenu.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent">
  
    <ImageView android:id="@+id/imgHead" android:layout_width="wrap_content" android:src="@drawable/icon" android:layout_height="wrap_content" android:layout_alignParentTop="true" android:layout_alignParentLeft="true"></ImageView>
    <TextView android:layout_width="wrap_content" android:id="@+id/tvName" android:layout_height="wrap_content" android:text="姓名" android:layout_alignBottom="@+id/imgHead" android:layout_toRightOf="@+id/imgHead" android:layout_marginLeft="34dp" android:layout_marginBottom="15dp"></TextView>
</RelativeLayout>
第二步、设计Activity  ContextMenuActivity.java
 
/**
 *
 */
package com.figo.helloworld;
 
import android.app.Activity;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.Menu;
import android.view.MenuItem;
import android.view.SubMenu;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
 
/**
 * @author zhuzhifei
 *
 */
public class ContextMenuActivity extends Activity {
         TextView tvName;
         ImageView imgHead;
 
         @Override
         protected void onCreate(Bundle savedInstanceState) {
                   // TODO Auto-generated method stub
                   super.onCreate(savedInstanceState);
                   setContentView(R.layout.contextmenu);
                   tvName = (TextView) findViewById(R.id.tvName);
                   imgHead = (ImageView) findViewById(R.id.imgHead);
                   // 给两个view注册上下文菜单
                   this.registerForContextMenu(tvName);
                   this.registerForContextMenu(imgHead);
         }
 
         // 创建上下文菜单
 
         @Override
         public void onCreateContextMenu(ContextMenu menu, View v,
                            ContextMenuInfo menuInfo) {
                   // TODO Auto-generated method stub
                   super.onCreateContextMenu(menu, v, menuInfo);
                   switch (v.getId()) {
                   case R.id.tvName:
                            menu.setHeaderIcon(R.drawable.icon);
            menu.setHeaderTitle("测试上下文菜单");
            //menu.clearHeader();
            //　第一个参数：组ID
            //　第二个参数：菜单项ID
            //　第三个参数：顺序号
            //　第四个参数：菜单项上显示的内容
            menu.add(1,0,0,"菜单1");
            menu.add(1,1,1,"菜单2").setCheckable(true); //　增加一个√选项
 
 
                            break;
                   case R.id.imgHead:
                            // ContextMenu.addSubMenu("菜单名称")　-　用来添加子菜单。子菜单其实就是一个特殊的菜单
                            SubMenu sub1 = menu.addSubMenu("父菜单1");
                            sub1.setHeaderIcon(R.drawable.icon);
                            sub1.add(0, 0, 0, "菜单1");
                            sub1.add(0, 1, 1, "菜单2");
                            sub1.setGroupCheckable(1, true, true);
                            SubMenu sub2 = menu.addSubMenu("父菜单2");
                            sub2.setIcon(R.drawable.icon);
                            sub2.add(1, 0, 0, "菜单3");
                            sub2.add(1, 1, 1, "菜单4");
                            sub2.setGroupCheckable(1, true, true);
 
                            break;
                   }
         }
 
         @Override
         public void openContextMenu(View view) {
                   // TODO Auto-generated method stub
                   super.openContextMenu(view);
         }
         @Override
         public boolean onContextItemSelected(MenuItem item) {
                   // TODO Auto-generated method stub
                   // return super.onContextItemSelected(item);
                   Toast.makeText(getApplicationContext(),"您选的菜单GroupId:"+item.getGroupId()+",ItemId:"+item.getItemId()+",Order:"+item.getOrder()+",Title:"+ item.getTitle(), Toast.LENGTH_LONG).show();
                 
                   return true;
         }
  
         @Override
         public void onContextMenuClosed(Menu menu) {
                   // TODO Auto-generated method stub
                   super.onContextMenuClosed(menu);
         }
 
}
 
第三步、AndroidManifest.xml 注册Activity
 
    <activity android:name=".ContextMenuActivity">
           <intent-filter>
              <action android:name="android.intent.action.MAIN" />
              <category android:name="android.intent.category.LAUNCHER" />
           </intent-filter>
       </activity>
第四步、运行效果