Java语言程序设计的课程设计项目——利用Java实现地球系动画完整实现实例（第4部分）

1、1.1 利用Java实现地球系动画完整实现实例（第4部分）1.1.1 产生地球和月亮、并且月亮围着地球转1、如何实现？（1）什么是软件需求 “产生地球和月亮、并且月亮围着地球转。”（2）什么是软件设计（思考） 设计的结果其实就是产生出“解决方案”。（3）什么是软件开发实现（编程）程序员按照设计人员的设计文档进行编程实现。（4）什么是软件测试找出程序中的“各种缺陷（Bug）”（5）部署和维护一、第一步：创建两个地球线程1、EarthPlanetApplet程序代码wt.Graphics;import java.awt.Image;import java.awt.MediaTracker;impo

2、rt java.awt.Rectangle;import java.awt.Toolkit;import javax.swing.JApplet;import .URL;public class EarthPlanetApplet extends JApplet implements Runnableprivate Thread earthMultiThread = null;private Thread moonMultiThread = null;private Graphics guiGraphics;private Image allImagesArray;private int cu

3、rrentImageIndex=0;private int imageWidth = 0;private int imageHeight = 0;private boolean allImagesLoaded = false;private final int NUMBER_IMAGES = 18;private boolean isRunedByApplication = false;public static void main(String args) EarthPlanetFrame applicationJFrame=null;applicationJFrame=new EarthP

4、lanetFrame("利用Java实现的地球系动画");EarthPlanetApplet threadApplet=null;threadApplet=new EarthPlanetApplet();applicationJFrame.getContentPane().add("Center", threadApplet);threadApplet.isRunedByApplication = true;threadApplet.init();threadApplet.start();applicationJFrame.setVisible(true

5、); public EarthPlanetApplet()public void start()if (earthMultiThread = null)earthMultiThread = new Thread(this);earthMultiThread.start();if (moonMultiThread = null) /创建出第2个线程对象moonMultiThread = new Thread(this);moonMultiThread.start();public void stop()if (earthMultiThread != null)earthMultiThread.s

6、top();earthMultiThread = null;if (moonMultiThread != null) /销毁线程对象moonMultiThread.stop();moonMultiThread = null;public void loadAllEarthImage()guiGraphics = getGraphics();allImagesArray = new ImageNUMBER_IMAGES;MediaTracker tracker = new MediaTracker(this);String strImage;for (int currentIndex = 1;

7、currentIndex <= NUMBER_IMAGES; currentIndex+)strImage = "/images/img00" + (currentIndex < 10) ? "0" : "") + currentIndex + ".gif"URL oneImageURL=getClass().getResource(strImage);if (isRunedByApplication)allImagesArraycurrentIndex-1 =Toolkit.getDefaultToo

8、lkit().getImage(oneImageURL);else allImagesArraycurrentIndex-1 = getImage(oneImageURL); tracker.addImage(allImagesArraycurrentIndex-1, 0);try tracker.waitForAll(); catch (InterruptedException e) e.printStackTrace();allImagesLoaded = !tracker.isErrorAny();if (!allImagesLoaded) stop(); guiGraphics.dra

9、wString("图像加载错误，可能是没有找到文件！", 10, 40); return;imageWidth = allImagesArray0.getWidth(this);imageHeight = allImagesArray0.getHeight(this);public void run() if (!allImagesLoaded) loadAllEarthImage(); repaint();while (true)trydisplayImage(guiGraphics);currentImageIndex+;if (currentImageIndex =

10、NUMBER_IMAGES)currentImageIndex = 0;Thread.sleep(50);catch (InterruptedException e)stop();private void displayImage(Graphics g) /分别显示两个地球图像if (!allImagesLoaded)return; if(Thread.currentThread()=earthMultiThread)g.drawImage(allImagesArraycurrentImageIndex, (getSize().width - imageWidth) / 2, (getSize

11、().height - imageHeight) / 2, null); else /改变坐标位置 g.drawImage(allImagesArraycurrentImageIndex, (getSize().width - imageWidth) / 4, (getSize().height - imageHeight) / 4, null);public void paint(Graphics g)if (allImagesLoaded)unds();g.clearRect(r.x, r.y, r.width, r.height);displayImage(g);elseg.drawSt

12、ring("正在加载图像，请等待.", 10, 20);上面的代码主要是再创建出第2个线程，并显示出第2套图像。其中的getClipBounds方法得到代表画板边界的矩形，然后从这个矩形中提取宽度和高度数据，再清除该矩形区域。如果除掉下面的语句，将会出现什么现象？g.clearRect(r.x, r.y, r.width, r.height);2、Applet程序方式执行（两个转动的图像）3、应用程序方式执行（两个转动的图像）二、第二步：控制两个地球线程的旋转的速度1、需要补充的知识sleep(毫秒数)是Thread类的静态方法，它能够控制线程。如Thread.sleep(

13、1000)；该线程睡眠1秒钟，等1秒钟之后，继续余下代码执行。但在sleep 时间间隔期满后，线程不一定立即恢复执行。这是因为在那个时刻，其它线程可能正在运行而且没有被调度为放弃执行，除非出现下面的情况：1) “醒来”的线程具有更高的优先级。 2) 正在运行的线程因为其它原因而阻塞。2、EarthPlanetApplet程序的代码import java.awt.Graphics;import java.awt.Image;import java.awt.MediaTracker;import java.awt.Rectangle;import java.awt.Toolkit;imp

14、ort javax.swing.JApplet;import .URL;public class EarthPlanetApplet extends JApplet implements Runnableprivate Thread earthMultiThread = null;private Thread moonMultiThread = null;private Graphics guiGraphics;private Image allImagesArray;private int currentImageIndex=0;private int imageWidth = 0;priv

15、ate int imageHeight = 0;private boolean allImagesLoaded = false;private final int NUMBER_IMAGES = 18;private boolean isRunedByApplication = false;public static void main(String args) EarthPlanetFrame applicationJFrame=null;applicationJFrame=new EarthPlanetFrame("利用Java实现的地球系动画");EarthPlane

16、tApplet threadApplet=null;threadApplet=new EarthPlanetApplet();applicationJFrame.getContentPane().add("Center", threadApplet);threadApplet.isRunedByApplication = true;threadApplet.init();threadApplet.start();applicationJFrame.setVisible(true); public EarthPlanetApplet()public void start()i

17、f (earthMultiThread = null)earthMultiThread = new Thread(this);earthMultiThread.start();if (moonMultiThread = null)moonMultiThread = new Thread(this);moonMultiThread.start();public void stop()if (earthMultiThread != null)earthMultiThread.stop();earthMultiThread = null;if (moonMultiThread != null)moo

18、nMultiThread.stop();moonMultiThread = null;public void loadAllEarthImage()guiGraphics = getGraphics();allImagesArray = new ImageNUMBER_IMAGES;MediaTracker tracker = new MediaTracker(this);String strImage;for (int currentIndex = 1; currentIndex <= NUMBER_IMAGES; currentIndex+)strImage = "/ima

19、ges/img00" + (currentIndex < 10) ? "0" : "") + currentIndex + ".gif"URL oneImageURL=getClass().getResource(strImage);if (isRunedByApplication)allImagesArraycurrentIndex-1 =Toolkit.getDefaultToolkit().getImage(oneImageURL);else allImagesArraycurrentIndex-1 = getI

20、mage(oneImageURL); tracker.addImage(allImagesArraycurrentIndex-1, 0);try tracker.waitForAll(); catch (InterruptedException e) e.printStackTrace();allImagesLoaded = !tracker.isErrorAny();if (!allImagesLoaded) stop(); guiGraphics.drawString("图像加载错误，可能是没有找到文件！", 10, 40); return;imageWidth = a

21、llImagesArray0.getWidth(this);imageHeight = allImagesArray0.getHeight(this);public void run() if (!allImagesLoaded) loadAllEarthImage(); repaint();while (true)trydisplayImage(guiGraphics);currentImageIndex+;if (currentImageIndex = NUMBER_IMAGES)currentImageIndex = 0;if(Thread.currentThread()=earthMu

22、ltiThread)Thread.sleep(50);elseThread.sleep(500);catch (InterruptedException e)stop();private void displayImage(Graphics g)if (!allImagesLoaded)return;if(Thread.currentThread()=earthMultiThread)g.drawImage(allImagesArraycurrentImageIndex, (getSize().width - imageWidth) / 2, (getSize().height - image

23、Height) / 2, null); else g.drawImage(allImagesArraycurrentImageIndex, (getSize().width - imageWidth) / 4, (getSize().height - imageHeight) / 4, null);public void paint(Graphics g)if (allImagesLoaded)Rectangle r = g.getClipBounds();g.clearRect(r.x, r.y, r.width, r.height);displayImage(g);elseg.drawSt

24、ring("正在加载图像，请等待.", 10, 20);在程序中通过对两个不同的线程采用不同的“休眠”时间，控制两个线程的频率，相应地也就达到控制地球的“自转”，并且还能够控制“自转”的速度。3、Applet程序方式执行，但此时的两个球的旋转速度有差别4、应用程序方式执行，但此时的两个球的旋转速度有差别三、第三步：月亮围着地球转1、需要补充的知识圆周方程 （1）下面的earthCenterX0、earthCenterY0代表地球的圆心坐标earthCenterX0=(getSize().width - imageWidth)/ 2;earthCenterY0=(getSiz

25、e().height - imageHeight)/2;（2）下面的moonCenterX0、moonCenterY0代表地球的圆心坐标moonCenterX0=earthCenterX0+circleRadius* Math.cos(currentRotatingAngle*Math.PI/180)；moonCenterY0=earthCenterY0+n(currentRotatingAngle*Math.PI/180)；因此，为了能够产生动态的运行效果，需要在显示图片的同时改变图像显示的位置，连续不断地在不同位置处画出地球的图像。2、EarthPlanetApplet程序代码import

26、 java.awt.Graphics;import java.awt.Image;import java.awt.MediaTracker;import java.awt.Rectangle;import java.awt.Toolkit;import .URL;import javax.swing.JApplet;public class EarthPlanetApplet extends JApplet implements Runnableprivate Thread earthMultiThread = null;private Thread moonMultiThread = nul

27、l;private boolean isRunedByApplication = false; /设置程序执行的方式private Graphics guiGraphics;/下面的变量都是与图像有关的变量private Image allImagesArray;private int currentImageIndex=0;private int imageWidth = 0;private int imageHeight = 0;private boolean allImagesLoaded = false;private final int NUMBER_IMAGES = 18;int

28、earthCenterX0,earthCenterY0,moonCenterX0,moonCenterY0;int currentRotatingAngle=0;int circleRadius=100;public EarthPlanetApplet()public static void main(String args) EarthPlanetFrame applicationJFrame=null;applicationJFrame=new EarthPlanetFrame("利用Java实现的地球系动画");EarthPlanetApplet threadAppl

29、et=null;threadApplet=new EarthPlanetApplet();applicationJFrame.getContentPane().add("Center", threadApplet);applicationJFrame.setVisible(true);threadApplet.isRunedByApplication = true;threadApplet.init();threadApplet.start(); public void start() /在重写的start()方法中创建线程对象if (earthMultiThread =

30、null)earthMultiThread = new Thread(this);earthMultiThread.start();if (moonMultiThread = null)moonMultiThread = new Thread(this);moonMultiThread.start();public void stop() /在重写的stop()方法中销毁线程对象if (earthMultiThread != null) earthMultiThread.stop(); /注意终止线程的方式应该采用其它更好的形式earthMultiThread = null;if (moonM

31、ultiThread != null)moonMultiThread.stop(); /注意终止线程的方式应该采用其它更好的形式moonMultiThread = null;public void loadAllEarthImage()guiGraphics = getGraphics();allImagesArray = new ImageNUMBER_IMAGES;MediaTracker tracker = new MediaTracker(this);String strImage = null;for (int currentIndex = 1; currentIndex <=

32、 NUMBER_IMAGES; currentIndex+)strImage = "/images/img00" + (currentIndex < 10) ? "0" : "") + currentIndex + ".gif"URL oneImageURL=getClass().getResource(strImage);if (isRunedByApplication)allImagesArraycurrentIndex-1 =Toolkit.getDefaultToolkit().getImage(on

33、eImageURL);else allImagesArraycurrentIndex-1 = getImage(oneImageURL); tracker.addImage(allImagesArraycurrentIndex-1, 0);try rAll(); catch (InterruptedException e) e.printStackTrace();allImagesLoaded = !tracker.isErrorAny();/allImagesLoaded = tracker.checkAll();if (!allImagesLoaded) stop(); guiGraphi

34、cs.drawString("图像加载错误，可能是没有找到文件！", 10, 20); return;imageWidth = allImagesArray0.getWidth(this); /获取被加载的图像的高度imageHeight = allImagesArray0.getHeight(this);/获取被加载的图像的宽度public void run() if (!allImagesLoaded) loadAllEarthImage(); repaint();while(true)trydisplayImage(guiGraphics);currentImageI

35、ndex+;if (currentImageIndex = NUMBER_IMAGES)currentImageIndex = 0;if(Thread.currentThread()=this.earthMultiThread)Thread.sleep(50);elseThread.sleep(10);catch (InterruptedException e)stop();private void displayImage(Graphics g)if (!allImagesLoaded) /识别所有的图像文件是否已经加载完毕return;this.earthCenterX0=(getSize

36、().width - imageWidth) / 2;this.earthCenterY0=(getSize().height - imageHeight) / 2;if(Thread.currentThread()=this.earthMultiThread)g.drawImage(allImagesArraycurrentImageIndex,earthCenterX0,earthCenterY0, null);elsethis.moonCenterX0=earthCenterX0+(int)(this.circleRadius*Math.cos(currentRotatingAngle*

37、Math.PI/180);this.moonCenterY0=earthCenterY0+(int)(this.circleRadius*Math.sin(currentRotatingAngle*Math.PI/180);g.drawImage(allImagesArraycurrentImageIndex,moonCenterX0,moonCenterY0, null);this.currentRotatingAngle+;if(currentRotatingAngle>360)currentRotatingAngle=0;public void paint(Graphics g)i

38、f (allImagesLoaded)/Rectangle r = g.getClipBounds();g.clearRect(0, 0, this.getWidth(), this.getHeight();displayImage(g);elseg.drawString("正在加载图像，请等待.", 10, 20);在displayImage()方法中图片显示的位置。3、测试现在的效果背景图上留下每个动作的残迹，因此必须对图像进行擦除。再次明确计算机实现动画的思路是：定位、画、擦除、再画、再擦除。其中擦除图像的方法决定着该动画的制作方法。所以，擦除图像成了制作动画的一个关

39、键部分。4、实现清除的相关功能实现的代码示例import java.awt.Graphics;import java.awt.Image;import java.awt.MediaTracker;import java.awt.Rectangle;import java.awt.Toolkit;import javax.swing.JApplet;import .URL;public class EarthPlanetApplet extends JApplet implements Runnableprivate Thread earthMultiThread = null;private

40、Thread moonMultiThread = null;private Graphics guiGraphics;private Image allImagesArray;private int currentImageIndex=0;private int imageWidth = 0;private int imageHeight = 0;private boolean allImagesLoaded = false;private final int NUMBER_IMAGES = 18;private boolean isRunedByApplication = false;int

41、 currentRotatingAngle=0;int earthCenterX0,earthCenterY0,moonCenterX0,moonCenterY0;int circleRadius=100;public static void main(String args) EarthPlanetFrame applicationJFrame=null;applicationJFrame=new EarthPlanetFrame("利用Java实现的地球系动画");EarthPlanetApplet threadApplet=null;threadApplet=new

42、EarthPlanetApplet();applicationJFrame.getContentPane().add("Center", threadApplet);threadApplet.isRunedByApplication = true;threadApplet.init();threadApplet.start();applicationJFrame.setVisible(true); public EarthPlanetApplet()public void start()if (earthMultiThread = null)earthMultiThread

43、 = new Thread(this);earthMultiThread.start();if (moonMultiThread = null)moonMultiThread = new Thread(this);moonMultiThread.start();public void stop()if (earthMultiThread != null)earthMultiThread.stop();earthMultiThread = null;if (moonMultiThread != null)moonMultiThread.stop();moonMultiThread = null;

44、public void loadAllEarthImage()guiGraphics = getGraphics();allImagesArray = new ImageNUMBER_IMAGES;MediaTracker tracker = new MediaTracker(this);String strImage;for (int currentIndex = 1; currentIndex <= NUMBER_IMAGES; currentIndex+)strImage = "/images/img00" + (currentIndex < 10) ?

45、"0" : "") + currentIndex + ".gif"URL oneImageURL=getClass().getResource(strImage);if (isRunedByApplication)allImagesArraycurrentIndex-1 =Toolkit.getDefaultToolkit().getImage(oneImageURL);else allImagesArraycurrentIndex-1 = getImage(oneImageURL); tracker.addImage(allImag

46、esArraycurrentIndex-1, 0);try tracker.waitForAll(); catch (InterruptedException e) e.printStackTrace();allImagesLoaded = !tracker.isErrorAny();if (!allImagesLoaded) stop(); guiGraphics.drawString("图像加载错误，可能是没有找到文件！", 10, 40); return;imageWidth = allImagesArray0.getWidth(this);imageHeight = allImagesArray0.getHeight(this);public void run() if (!allImagesLoaded) loadAllEarthImage(); repai