pageitem.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.Hashtable;

import javax.microedition.lcdui.Image;

/**
 * <p>
 * The <code>PageItem</code> defines a choice in a <code>MenuPage</code>.
 * An item can have a subpage and/or an <code>ItemAction</code> implementation.
 * When an item is selected by user, the <code>ItemAction</code> implementation is
 * invoked, and/or a transition to the subpage is started.
 * </p><p>
 * <code>PageItem</code>s can also have key/value pairs typed as int/Object.
 * </p><p>
 * When there is both a subpage and an action; pressing fire on such an
 * item will first start a new thread invokinh the action, then the menu will navigate
 * to the subpage. If the user presses right on such an item, the action is not executed
 * but the subpage is navigated to.
 * </p>
 * @see Menu
 * @see MenuPage
 * @see ItemAction
 * @author Peter Andersson
 */
public class PageItem
{
  /** Centered item, image to the left of text (Default layout) */
  public static final int LAYOUT_CENTERED_LEFT = 0;
  /** Centered item, image to the right of text */
  public static final int LAYOUT_CENTERED_RIGHT = 1;
  /** Left aligned image, right aligned text */
  public static final int LAYOUT_ALIGN_LEFT = 2;
  /** Right aligned image, left aligned text */
  public static final int LAYOUT_ALIGN_RIGHT = 3;
  
  /** The label of the item */
  protected char[] m_label;
  /** The action of the item */
  protected ItemAction m_action;
  /** The next page to goto if this item is selected */
  protected MenuPage m_subPage;
  /** The image of this item */
  protected Image m_image;
  /** Layout of image */
  protected int m_layout = LAYOUT_CENTERED_LEFT;
  /** Enabled / disabled flag */
  protected boolean m_enabled = true;
  /** Properties table */
  protected Hashtable m_props = null;
  /** Item id */
  protected int m_id = Integer.MIN_VALUE;
  
  /**
   * Creates an item that is to be inserted into a <code>MenuPage</code>.
   * Item graphical elements are the label and the image, and logical
   * elements are action and subpage. 
   * 
   * @param label		The text label of this item or null if no text.
   * @param image		The image of this item or null if no image.
   * @param action		The action that is called when activating this item,
   * 					or null if no action.
   * @param subPage		The page that will be navigated to when activating this item,
   * 					or null of no such page.
   */
  public PageItem(char[] label, Image image, ItemAction action, MenuPage subPage)
  {
    setLabel(label);
    setImage(image);
    setAction(action);
    setSubPage(subPage);
  }
  
  /**
   * Creates an item that is to be inserted into a <code>MenuPage</code>.
   * Item graphical elements are the label and the image, and logical
   * elements are action and subpage. 
   * 
   * @param label		The text label of this item or null if no text.
   * @param image		The image of this item or null if no image.
   * @param action		The action that is called when activating this item,
   * 					or null if no action.
   * @param subPage		The page that will be navigated to when activating this item,
   * 					or null of no such page.
   * @param id			The id of this item.
   */
  public PageItem(char[] label, Image image, ItemAction action, MenuPage subPage, int id)
  {
    this(label, image, action, subPage);
    m_id = id;
  }
  
  /**
   * Returns ID of this item, or <code>Integer.MIN_VALUE</code> if not set.
   * @return The item id
   */
  public int getId()
  {
    return m_id;
  }
  
  /**
   * Called when this item is added to a page.
   * Default implementation does nothinhg.
   */
  public void addedToPage() {}
  
  /**
   * Returns the label of this item.
   * 
   * @return	The text label of this item.
   */
  public char[] getLabel()
  {
    return m_label;
  }
  /**
   * Sets the text label of this item.
   * 
   * @param label	The text label of this item.
   */
  public void setLabel(char[] label)
  {
    m_label = label;
  }
  /**
   * Returns the subpage that will be displayed when this
   * item is activated, or null if no such page.
   * 
   * @return	The sub page or null.
   */
  public MenuPage getSubPage()
  {
    return m_subPage;
  }
  /**
   * Sets the subpage that will be displayed when this
   * item is activated, or null if no such page.
   * 
   * @param page  The sub page or null.
   */
  public void setSubPage(MenuPage page)
  {
    m_subPage = page;
  }
  /**
   * Returns action which is called upon item activation.
   * 
   * @return The action of this item.
   */
  public ItemAction getAction()
  {
    return m_action;
  }
  /**
   * Sets the action which is called upon item activation.
   * 
   * @param action The action of this item.
   */
  public void setAction(ItemAction action)
  {
    m_action = action;
  }
  /**
   * Returns true if this item is enabled, false otherwise.
   * 
   * @return true if enabled, false otherwise
   */
  public boolean isEnabled()
  {
    return m_enabled;
  }
  /**
   * Enables or disables this item.
   * 
   * @param enabled true to enable, false to disable
   */
  public void setEnabled(boolean enabled)
  {
    m_enabled = enabled;
  }
  /**
   * Returns image of this item, or null if none set.
   * 
   * @return	The image or null.
   */
  public Image getImage()
  {
    return m_image;
  }
  /**
   * Sets the image of this item.
   * 
   * @param image	The image or null.
   */
  public void setImage(Image image)
  {
    m_image = image;
  }
  
  /**
   * Sets the layout of the image,
   * any of LAYOUT_CENTERED_LEFT, 
   * LAYOUT_CENTERED_RIGHT, LAYOUT_ALIGN_LEFT, LAYOUT_ALIGN_RIGHT.
   * @param layout	Image layout.
   */
  public void setLayout(int layout)
  {
    m_layout = layout;
  }
  
  /**
   * Returns the layout of the image,
   * any of LAYOUT_CENTERED_LEFT, 
   * LAYOUT_CENTERED_RIGHT, LAYOUT_ALIGN_LEFT, LAYOUT_ALIGN_RIGHT.
   * @return  Image layout.
   */
  public int getLayout()
  {
    return m_layout;
  }
  
  /**
   * Returns value of a generic property on this item
   * or null if not set.
   * 
   * @param key		The key of the property.
   * @return		The value of the property or null.
   */
  public Object getProperty(int key)
  {
    if (m_props == null)
      return null;
    else
      return m_props.get(new Integer(key));
  }
  /**
   * Sets a value to a generic property on this item, or
   * resets it by giving <code>null</code> as a value.
   * 
   * @param key		The key of the property.
   * @param value	The value of the property, or null to reset it.
   */
  public void setProperty(int key, Object value)
  {
    if (m_props == null)
    {
      m_props = new Hashtable();
    }
    if (value == null)
    {
      m_props.remove(new Integer(key));
    }
    else
    {
      m_props.put(new Integer(key), value);
    }
  }
}