menupage.java

手机播放交谈实时监控软件

// 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 <code>MenuPage</code> class represents a title and a number of choices in a <code>Menu</code>.
 * The <code>MenuPage</code>'s choices are added as <code>PageItem</code>s via the
 * <code>addItem</code> 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();
  }
}