www.pudn.com > Bluegammon蓝牙的应用编程.rar > PageItem.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.Hashtable; 
 
import javax.microedition.lcdui.Image; 
 
/** 
 * 
 
 * The PageItem defines a choice in a MenuPage. 
 * An item can have a subpage and/or an ItemAction implementation. 
 * When an item is selected by user, the ItemAction implementation is 
 * invoked, and/or a transition to the subpage is started. 
 * 
 
 * PageItems can also have key/value pairs typed as int/Object. 
 * 
 
 * 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. 
 * 
 
 * @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 MenuPage. 
   * 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 MenuPage. 
   * 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 Integer.MIN_VALUE 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 null 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); 
    } 
  } 
}