JAVA实验报告分析(7)

int x=0,y=0; Mycanvas(){

setSize(400,400);

setBackground(Color.lightGray); addMouseListener(this); }

public void paint(Graphics g) { g.setColor(Color.red);

g.drawString(\

int diameter = Math.min(this.getWidth()/2, this.getHeight()/2); g.setColor(Color.yellow);

g.fillOval(x,y,diameter,diameter); g.setColor(this.getBackground()); g.fillOval(x-20,y-20,diameter,diameter); }

public void mousePressed(MouseEvent e){ x=e.getX(); y=e.getY(); repaint(); }

public void mouseReleased(MouseEvent e){} public void mouseEntered(MouseEvent e){} public void mouseExited(MouseEvent e){} public void mouseClicked(MouseEvent e){ x=e.getX(); y=e.getY(); repaint(); }

public void update(Graphics g){ paint(g); super.update(g); } }

public class MoonJFrame{

public static void main(String args[]){ Frame f=new Frame();

f.setBounds(500,300,400,400); f.setVisible(true);

f.add(new Mycanvas(),\ f.validate(); } }

（实验二程序清单续4）

5.根据阿基米德螺线的极坐标方程：r=aθ画出相应图形。

import java.awt.*; import java.awt.event.*; import javax.swing.*;

public class ArchimedesJFrame extends JFrame implements ActionListener{ private ArchimedesCanvas archimedes; private JRadioButton radiob_color[]; public ArchimedesJFrame(){

super(\阿基米德螺线\);

Dimension dim=getToolkit().getScreenSize();

this.setBounds(dim.width/4,dim.height/4,dim.width/2,dim.height/2); this.setDefaultCloseOperation(EXIT_ON_CLOSE); JToolBar toolbar=new JToolBar(); this.getCntentPane().add(toolbar,\); String colorstr[]={\红\,\绿\,\蓝\};

ButtonGroup bgroup_color=new ButtonGroup(); radiob_color=new JRadioButton[colorstr.length]; for(int i=0;i

radiob_color[i]=new JRadioButton(colorstr[i]);

radiob_color[i].addActionListener(this);

bgroup_color.add(radiob_color[i]);

toolbar.add(radiob_color[i]); }

radiob_color[0].setSelected(true);

archimedes=new ArchimedesCanvas(Color.red); this.getContentPane().add(archimedes,\); this.setVisible(true); }

public void actionPerformed(ActionEvent e){ Color c=null;

if(e.getSource()==radiob_color[0])

c=new Color(255,0,0);

if(e.getSource()==radiob_color[1]){

c=new Color(0,255,0); }

if(e.getSource()==radiob_color[2])

c=new Color(0,0,255);

archimedes.setColor(c);

archimedes.repaint(); }

public static void main(String[] args){

new ArchimedesJFrame(); } }

class ArchimedesCanvas extends Canvas implements ComponentListener,FocusListener,ActionListener{

private Color color;

private Timer mTimer;

public ArchimedesCanvas(Color color){

this.setBackground(Color.WHITE);

this.setColor(color);

this.addComponentListener(this); this.addFocusListener(this); }

public void setColor(Color color){ this.color = color; }

public void paint(Graphics g){

int x0 = this.getWidth()/2; int y0 = this.getHeight()/2;

g.setColor(color); g.drawLine(x0,0,x0,y0*2); g.drawLine(0,y0,x0*2,y0); for (int i=0; i<4000; i++){ double angle = i*Math.PI/512; double radius = 0.5*angle;

int x=(int)Math.round(radius*angle*Math.cos(angle)); int y=(int)Math.round(radius*angle*Math.sin(angle)); mTimer=new Timer(1000,this); mTimer.start();

g.drawOval(x0+x,y0+y,1,1); } }

public void componentMoved(ComponentEvent e) {}

public void componentHidden(ComponentEvent e) {} public void componentResized(ComponentEvent e) {

this.repaint(); }

public void componentShown(ComponentEvent e) {} public void focusGained(FocusEvent arg0){

mTimer.stop(); }

public void focusLost(FocusEvent arg0){

mTimer.restart(); }

public void actionPerformed(FocusEvent arg0){} public void actionPerformed(ActionEvent e) {} }

四、实验结果与分析

（分析每题采用的布局管理器、事件处理类和主要功能实现方法。） 结果：

（1）输出结果：

（2）输出结果：

（3）输出结果：

点击“平均分”按钮后：

正常显示结果如下：

（4）输出结果：

点击鼠标后：