www.pudn.com > Bluegammon蓝牙的应用编程.rar > MenuPage.java

// Copyright (c) 2005 Sony Ericsson Mobile Communications AB 
// 
// This software is provided "AS IS," without a warranty of any kind.  
// ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES,  
// INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A  
// PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED.  
// 
// THIS SOFTWARE IS COMPLEMENTARY OF JAYWAY AB (www.jayway.se) 
 
package bluegammon.gui.menu; 
 
import java.util.Vector; 
 
import javax.microedition.lcdui.Image; 
 
/** 
 * A MenuPage class represents a title and a number of choices in a Menu. 
 * The MenuPage's choices are added as PageItems via the 
 * addItem method.  
 * @see bluegammon.gui.menu.Menu 
 * @see bluegammon.gui.menu.PageItem 
 * @author Peter Andersson 
 */ 
public class MenuPage 
{ 
  /** Left aligned image, right aligned text */ 
  public static final int LAYOUT_LEFT = 0; 
  /** Right aligned image, left aligned text */ 
  public static final int LAYOUT_RIGHT = 1; 
 
  /** The title of the page */ 
  protected char[] m_title; 
  /** The title image of the page */ 
  protected Image m_titleImage; 
  /** The alignment of title and image */ 
  protected int m_layout = LAYOUT_LEFT; 
  /** The page items */ 
  protected Vector m_items = new Vector(); 
  /** Current selected item index */ 
  protected int m_currentIndex = -1; 
   
  /** 
   * Creates a new page for a menu. 
   * @param title			The title of the page or null. 
   * @param titleImage		The image of the page or null. 
   */ 
  public MenuPage(char[] title, Image titleImage) 
  { 
    setTitle(title); 
    setTitleImage(titleImage); 
  } 
   
  /** 
   * Sets the layout of the image, 
   * any of LAYOUT_LEFT, LAYOUT_RIGHT. 
   * @param layout	Image layout. 
   */ 
  public void setLayout(int layout) 
  { 
    m_layout = layout; 
  } 
   
  /** 
   * Returns the layout of the image, 
   * any of LAYOUT_LEFT, LAYOUT_RIGHT. 
   * @return  Image layout. 
   */ 
  public int getLayout() 
  { 
    return m_layout; 
  } 
  /** 
   * Returns the title of this page. 
   *  
   * @return	The page title. 
   */ 
  public char[] getTitle() 
  { 
    return m_title; 
  } 
  /** 
   * Sets the title of this page. 
   *  
   * @param title	The page title. 
   */ 
  public void setTitle(char[] title) 
  { 
    m_title = title; 
  } 
  /** 
   * Returns the title of this page. 
   *  
   * @return	The page title image. 
   */ 
  public Image getTitleImage() 
  { 
    return m_titleImage; 
  } 
  /** 
   * Sets the title image of this page. 
   *  
   * @param titleImage	The page title iamge. 
   */ 
  public void setTitleImage(Image titleImage) 
  { 
    m_titleImage = titleImage; 
  } 
  /** 
   * Adds an item to this page. 
   *  
   * @param item	The item to add. 
   */ 
  public synchronized void addItem(PageItem item) 
  { 
    m_items.addElement(item); 
    item.addedToPage(); 
    if (m_currentIndex == -1) 
    { 
      m_currentIndex = 0; 
    } 
  } 
  /** 
   * Removes an item from this page. 
   *  
   * @param item	The item to remove. 
   */ 
  public synchronized void removeItem(PageItem item) 
  { 
    m_items.removeElement(item); 
    if (size() == 0) 
    { 
      m_currentIndex = -1; 
    } 
  } 
  /** 
   * Removes the item at specified index from this page. 
   *  
   * @param index	The index of the item to remove. 
   */ 
  public synchronized void removeItem(int index) 
  { 
    m_items.removeElementAt(index); 
  } 
  /** 
   * Returns number of items in this page. 
   *  
   * @return	Number of items. 
   */ 
  public synchronized int size() 
  { 
    return m_items.size(); 
  } 
  /** 
   * Returns the currently selected index in this page. In  
   * special cases this method may return -1, for no selected 
   * items. 
   *  
   * @return	Selected item index. 
   */ 
  public synchronized int getSelectedIndex() 
  { 
    PageItem item = itemAt(m_currentIndex); 
    if (item != null && !item.isEnabled()) 
    { 
      setSelectedIndex(m_currentIndex+1); 
    } 
    return m_currentIndex; 
  } 
  /** 
   * Sets the currently selected index in this page. 
   * If the index is greater than number of items in the 
   * page, it is wrapped to the first item. If the index 
   * is below zero, it is wrapped to the last item. 
   * If correct index is not possible to set index 
   * will be set to -1. This happens if there are no items, 
   * or all items are disabled. 
   *  
   * @param index	Index of selected item. 
   */ 
  public synchronized void setSelectedIndex(int index) 
  { 
    int size = size(); 
    boolean dirDown = index - m_currentIndex > 0; 
    boolean allDisabled = true; 
    for (int i = 0; allDisabled && i < size; i++) 
    { 
      allDisabled = !itemAt(i).isEnabled(); 
    }  
    if (size == 0 || allDisabled) 
    { 
      index = -1; 
    } 
    else 
    { 
      boolean enabled = true; 
      do 
      {   
        if (index >= size) 
        { 
          index = 0; 
        } 
        else if (index < 0) 
        { 
          index = size - 1; 
        } 
        enabled = itemAt(index).isEnabled(); 
        if (!enabled) 
        { 
          if (dirDown) 
          { 
            index++; 
          } 
          else 
          { 
            index--; 
          } 
        } 
      } while (!enabled); 
    } 
    m_currentIndex = index; 
  } 
  /** 
   * Returns item at specified index. 
   *  
   * @param index	The index of the idem 
   * @return	The item at specified index, or null if not found. 
   */ 
  public synchronized PageItem itemAt(int index) 
  { 
    if (index < 0 || index >= size()) 
    { 
      return null; 
    } 
    else 
    { 
      return (PageItem)m_items.elementAt(index); 
    } 
  } 
  /** 
   * Returns the index of specified item. It this item does 
   * not belong to the list, -1 is returned. 
   *  
   * @param item 	The item whose index to find. 
   * @return index of the item, or -1 if item is not part of the menu. 
   */ 
  public synchronized int getIndex(PageItem item) 
  { 
    return m_items.indexOf(item); 
  } 
 
  /** 
   * Removes all items on this page 
   */ 
  public synchronized void removeAllItems() 
  { 
    m_items.removeAllElements(); 
  } 
}