Android之菜单二——上下文菜单

上下文菜单不同于选项菜单，选项菜单服务于Activity，而上下文菜单则是注册到某个View对象上的。

如果一个View对象注册了上下文菜单，用户可以通过长按该View对象以呼出上下文菜单。

上下文菜单不支持快捷键，其菜单选项也不能附带图标，但是可以为上下文菜单的标题指定图标。

以下模拟上下文菜单

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
   
     "
   
     >
   
     
 
   
     <
   
     EditText android:text
   
     =
   
     "
   
     第一文本框
   
     "
   
      
 android:id
   
     =
   
     "
   
     @+id/editText01
   
     "
   
     
 android:layout_width
   
     =
   
     "
   
     fill_parent
   
     "
   
     
 android:layout_height
   
     =
   
     "
   
     wrap_content
   
     "
   
      
   
     />
   
     
 
   
     <
   
     EditText android:text
   
     =
   
     "
   
     第二文本框
   
     "
   
      
 android:id
   
     =
   
     "
   
     @+id/editText02
   
     "
   
     
 android:layout_width
   
     =
   
     "
   
     fill_parent
   
     "
   
     
 android:layout_height
   
     =
   
     "
   
     wrap_content
   
     "
   
      
   
     />
   
     

   
     </
   
     LinearLayout
   
     >
  
    

MeunActivity类

  
    

   
     package
   
      com.ljq.activity;


   
     import
   
      android.app.Activity;

   
     import
   
      android.os.Bundle;

   
     import
   
      android.view.ContextMenu;

   
     import
   
      android.view.MenuItem;

   
     import
   
      android.view.View;

   
     import
   
      android.view.ContextMenu.ContextMenuInfo;

   
     import
   
      android.widget.EditText;


   
     public
   
      
   
     class
   
      MeunActivity 
   
     extends
   
      Activity {
 
   
     private
   
      EditText editText01
   
     =
   
     null
   
     ;
 
   
     private
   
      EditText editText02
   
     =
   
     null
   
     ;
 
 
   
     private
   
      
   
     final
   
      
   
     int
   
      MENU1 
   
     =
   
      
   
     1
   
     ;
 
   
     private
   
      
   
     final
   
      
   
     int
   
      MENU2 
   
     =
   
      
   
     2
   
     ;
 
   
     private
   
      
   
     final
   
      
   
     int
   
      MENU3 
   
     =
   
      
   
     3
   
     ;
 
   
     private
   
      
   
     final
   
      
   
     int
   
      MENU4 
   
     =
   
      
   
     4
   
     ;
 
   
     private
   
      
   
     final
   
      
   
     int
   
      MENU5 
   
     =
   
      
   
     5
   
     ;
 
 @Override
 
   
     protected
   
      
   
     void
   
      onCreate(Bundle savedInstanceState) {
 
   
     super
   
     .onCreate(savedInstanceState);
 setContentView(R.layout.main);
 
 editText01
   
     =
   
     (EditText)findViewById(R.id.editText01);
 editText02
   
     =
   
     (EditText)findViewById(R.id.editText02);
 
 
   
     //
   
     为View对象注册上下文菜单
   
     

   
      
   
     this
   
     .registerForContextMenu(editText01);
 
   
     this
   
     .registerForContextMenu(editText02);
 }
 
 
   
     /**
   
     
 * 初始化上下文菜单
 * 
 * 每次调出上下文菜单时都会被调用一次
 
   
     */
   
     
 @Override
 
   
     public
   
      
   
     void
   
      onCreateContextMenu(ContextMenu menu, View v,
 ContextMenuInfo menuInfo) {
 menu.setHeaderIcon(R.drawable.header);
 
   
     switch
   
      (v.getId()) {
 
   
     case
   
      R.id.editText01:
 menu.add(
   
     0
   
     , MENU1, 
   
     0
   
     , 
   
     "
   
     菜单项1
   
     "
   
     );
 menu.add(
   
     0
   
     , MENU2, 
   
     0
   
     , 
   
     "
   
     菜单项2
   
     "
   
     );
 menu.add(
   
     0
   
     , MENU3, 
   
     0
   
     , 
   
     "
   
     菜单项3
   
     "
   
     );
 
   
     break
   
     ;
 
   
     case
   
      R.id.editText02:
 menu.add(
   
     0
   
     , MENU4, 
   
     0
   
     , 
   
     "
   
     菜单项4
   
     "
   
     );
 menu.add(
   
     0
   
     , MENU5, 
   
     0
   
     , 
   
     "
   
     菜单项5
   
     "
   
     );
 
   
     break
   
     ;
 }
 
   
     //
   
     super.onCreateContextMenu(menu, v, menuInfo);
   
     

   
      }
 
 
   
     /**
   
     
 * 当用户选择了上下文菜单选项后调用该事件
 
   
     */
   
     
 @Override
 
   
     public
   
      
   
     boolean
   
      onContextItemSelected(MenuItem item) {
 
   
     switch
   
      (item.getItemId()) {
 
   
     case
   
      MENU1:
 
   
     case
   
      MENU2:
 
   
     case
   
      MENU3:
 editText01.append(
   
     "
   
     \n
   
     "
   
     +
   
     item.getTitle()
   
     +
   
     "
   
     被按下
   
     "
   
     );
 
   
     break
   
     ;
 
   
     case
   
      MENU4:
 
   
     case
   
      MENU5:
 editText02.append(
   
     "
   
     \n
   
     "
   
     +
   
     item.getTitle()
   
     +
   
     "
   
     被按下
   
     "
   
     );
 
   
     break
   
     ;
 }
 
   
     return
   
      
   
     true
   
     ;
 }
 
}
  
    

运行结果

1、 2、