KT.rar_kt java_骑士

import java.applet.Applet; import java.awt.*; import java.awt.event.*; import java.net.URL; import java.util.ArrayList; public class KT extends Applet { // 线程延迟以毫秒为单位 public final static int DELAY = 500; // 开始骑士巡游线程 private Thread thd; // 初始化小程序 public void init () { // 创建一个标签对象来标明小程序的标题 Label lblTitle = new Label ("Knight's Tour", Label.CENTER); lblTitle.setFont (new Font ("Arial", Font.BOLD, 18)); // 把标签对象加到小程序的面板容器 add (lblTitle); // 创建一个ChessBoard对象,它具有显示一个棋盘、移动骑士到 // 任何方格并留下骑士巡游轨迹的能力. final ChessBoard cb = new ChessBoard (this); //把ChessBoard对象加入到小程序的面板容器 add (cb); // 创建一个Panel对象来保存Label,Choice和按钮对象. Panel pnl = new Panel (); //创建一个标签来标明Choice对象并把它添加到Panel中 pnl.add (new Label ("Choose starting position:")); //创建一个Choice对象,用来选择骑士的开始位置（棋盘的四个角落） //并把它添加到Panel中. final Choice c = new Choice (); c.add ("Upperleft corner"); c.add ("Upperright corner"); //创建Choice的item listener,这个监听器按选择结果来重设骑士的开始位置. c.addItemListener (new ItemListener () { public void itemStateChanged (ItemEvent e) { Choice c = (Choice) e.getSource (); if (c.getSelectedIndex () == 0) cb.moveKnight (1); else cb.moveKnight (8); cb.reset (); } }); pnl.add (c); //把Panel加入到小程序的面板容器 add (pnl); //创建一个按钮对象用来开始骑士巡游. final Button btn = new Button ("Take the Tour"); //创建按钮的Action listener(动作监听器),用来确定骑士巡游的位置. //按照规则将骑士从一个位置移动到另一个位置. ActionListener al; al = new ActionListener () { public void actionPerformed (ActionEvent e) { Runnable r; r = new Runnable () { int [] boardPositions1 = { 1, 18, 33, 50, 60, 54, 64, 47, 32, 15, 5, 11, 17, 34, 49, 59, 53, 63, 48, 31, 16, 6, 12, 2, 19, 25, 42, 57, 51, 61, 55, 40, 23, 8, 14, 4, 10, 27, 44, 38, 21, 36, 46, 29, 35, 41, 58, 52, 62, 56, 39, 24, 7, 13, 3, 9, 26, 43, 37, 22, 28, 45, 30, 20 }; int [] boardPositions2 = { 8, 23, 40, 55, 61, 51, 57, 42, 25, 10, 4, 14, 24, 39, 56, 62, 52, 58, 41, 26, 9, 3, 13, 7, 22, 32, 47, 64, 54, 60, 50, 33, 18, 1, 11, 5, 15, 30, 45, 35, 20, 37, 43, 28, 38, 48, 63, 53, 59, 49, 34, 17, 2, 12, 6, 16, 31, 46, 36, 19, 29, 44, 27, 21 }; public void run () { cb.reset (); // thd用来检查用户离开小程序网页 　　　　　　　　　　　　　　　　　// 以便停止小程序的运行. for (int i = 0; i < boardPositions1.length && thd != null; i++) { if (c.getSelectedIndex () == 0) cb.moveKnight (boardPositions1 [i]); else cb.moveKnight (boardPositions2 [i]); try { Thread.sleep (DELAY); } catch (InterruptedException e2) { } } c.setEnabled (true); btn.setEnabled (true); } }; c.setEnabled (false); btn.setEnabled (false); thd = new Thread (r); thd.start (); } }; btn.addActionListener (al); //添加按钮到小程序面板容器 add (btn); } //停止小程序 public void stop () { //用户离开网页时必须停止”骑士巡游”线程 thd = null; } } final class ChessBoard extends Canvas { //非白色方格的颜色 private final static Color SQUARECOLOR = new Color (195, 214, 242); //棋盘方格的尺寸 private final static int SQUAREDIM = 40; //棋盘方格的尺寸（包括黑边框） private final static int BOARDDIM = 8 * SQUAREDIM + 2; //棋盘左上角的左坐标（X坐标） private int boardx; //棋盘左上角的顶坐标(Y坐标) private int boardy; //棋盘长度 private int width; // 棋盘宽度 private int height; // 图像缓冲 private Image imBuffer; // Graphics context associated with image buffer. private Graphics imG; // 骑士图像 private Image imKnight; // 骑士图像的长度 private int knightWidth; // 骑士图像的宽度 private int knightHeight; //骑士轨迹的坐标 private ArrayList trail; // Left coordinate of knight rectangle origin (upper-left corner). private int ox; // Top coordinate of knight rectangle origin (upper-left corner). private int oy; // 创建ChessBoard的Applet--调用它的getImage()和getDocumentBase()方法, // 并且我们将使用它作为drawImage()方法的image observer Applet a; // 构造棋盘 ChessBoard (Applet a) { // 确定部件的大小 width = BOARDDIM+1; height = BOARDDIM+1; // 初始化棋盘, 使它处于中央 boardx = (width - BOARDDIM) / 2 + 1; boardy = (height - BOARDDIM) / 2 + 1; //使用MediaTracker来确保骑士图像在我们获取它的长和宽之前被完全导入 MediaTracker mt = new MediaTracker (this); // 导入骑士图像 imKnight = a.getImage (a.getDocumentBase (), "knight.gif"); mt.addImage (imKnight, 0); try { mt.waitForID (0); } catch (InterruptedException e) {} //获得骑士的长度和宽度, 帮助骑士定位于方格中央 knightWidth = imKnight.getWidth (a); knightHeight = imKnight.getHeight (a); //初始化骑士图像, 使骑士定位于左上角方格的中央 ox = boardx + (SQUAREDIM - knightWidth) / 2 + 1; oy = boardy + (SQUAREDIM - knightHeight) / 2 + 1; //创建一个数据结构, 用来保存骑士巡游时的轨迹 trail = new ArrayList (); //保存applet引用以便后面调用drawImage()时使用. this.a = a; } // This method is called when the ChessBoard component's peer is created. // The code in this method cannot be called in the ChessBoard constructor // because the createImage() method returns null at that point. It doesn't // return a meaningful value until the ChessBoard component has been added // to its container. The addNotify() method is not called until the first // time ChessBoard is added to a container.