menupage.java

J2ME 3D 第一人称射击迷宫类手机游戏源码。

package myGame.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 myGame.gui.menu.Menu
 * @see myGame.gui.menu.PageItem
 * @author YuBingxing
 */
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();
	}
}