云南大学软件学院JAVA实验九

Now when the user clicks on a space in the panel (outside a button), draw a circle with the current color. Have your application just add new circles when the user clicks the mouse. Do not erase previous circles.
Program 2
Create an application AddCircles that displays a panel. This panel will contain two buttons (one for red and one for blue). When the user clicks on a button, change a variable called currentColor to that particular color.
super.paint();
//设置背景颜色 g.setColor(Color.CYAN); g.fillRect(0, 0, 500, 500);
//画出不同颜色的固定圆 this.DrawBall(g, this.ball.getColor(), this.ball.getLocate()); }
public int getColor() { return color;
} public void setColor(int color) {
this.color = color; } public int getLocate() {
return locate; } public void setLocate(int locate) {
//定义一个画圆的函数 public void DrawBall(Graphics g,int color, int locate) {
switch(color) { case 0:
g.setColor(Color.WHITE); break; case 1: g.setColor(Color.BLUE); break; case 2: g.setColor(Color.RED); break; } g.fillOval(locate, locate, 150, 150); }
this.add(jp,BorderLayout.NORTH); this.add(mp);
this.setTitle("ChangeBallColor"); this.setSize(500, 500); this.setLocation(300, 150); this.setVisible(true); this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); } }
this.add(jp,BorderLayout.NORTH); this.add(mp);
this.setTitle("ChangeBallColor"); this.setSize(500, 500); this.setLocation(300, 150); this.setVisible(true); this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); } }
//定义组件 JPanel jp; JButton jb1,jb2,jb3; MyPanel mp=null;
public static void main(String[] args) { // TODO Auto-generated method stub AddCircles main=new AddCircles();
三、实验内容：
Program 1：
Balls.java 代码部分
package Lab9;
class Balls { //定义圆的颜色 type，1 表示蓝色，2 表示红色 int color=0; //定义圆的位置 int locate=50;
public int getColor() { return color;
}
//构造函数 public AddCircles() {
mp=new MyPanel(); jp=new JPanel(); jb1=new JButton("蓝色"); jb2=new JButton("红色"); jb3=new JButton("增加一个同颜色的圆");
jp.add(jb1); jp.add(jb2); jp.add(jb3);
//构造函数 public Balls(int color, int locate) {
this.color=color; this.locate=locate; }
}
ChangeBallColor.java 代码部分
package Lab9;
import java.awt.*; import java.awt.event.*; import javax.swing.*;
//对事件的处理函数 public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub if(e.getActionCommand().equals("蓝色")) {
this.ball.setColor(1); this.ball.setLocate(150); }else if(e.getActionCommand().equals("红色")) { this.ball.setColor(2); this.ball.setLocate(150); }
this.locate = locate; }
//构造函数 public Balls(int color, int locate) {
this.color=color; this.locate=locate; } }
//增加圆的类 class AddBalls extends Balls {
public AddBalls(int color, int locate) {
//定义我的面板 class MyPanel extends JPanel implements ActionListener {
Balls ball=null; //创建一个集合，用于保存增加的圆 Vector<AddBalls> abList=new Vector<AddBalls>(); int i=150;//表示增加圆的位置，初始为 150 //构造函数 public MyPanel() {
云南大学软件学院
实验报告
姓名： 王增伟 学号： 20111120083 班级： 软件工程 日期： 2014.11.18 成绩：
JAVA 实验九
一、 实验目的：
熟悉 Java 中的图形化编程以及事件监听器的使用。
二、实验要求：
Program 1
Create an application ChangeBallColor that displays a panel. This panel will contain two buttons (one for red and one for blue). It will also display a filled in circle. When the user clicks on a button, the circle should change to that color. So, if a user clicks the blue button, the circle will change to blue. Similarly, if a user clicks the red button, the circle will turn to red.
public class ChangeBallColor extends JFrame {
//定义组件
JPanel jp; JButton jb1,jb2; Panel mp=null;
public static void main(String[] args) { // TODO Auto-generated method stub ChangeBallColor main=new ChangeBallColor();
//定义我的面板 class Panel extends JPanel implements ActionListener {
Balls ball=null;
//构造函数 public Panel() {
//初始化圆 ball=new Balls(0,150); }
public void paint(Graphics g) {
//重绘界面 this.repaint(); } }
运行结果显示： 初始颜色为白色：
点击蓝色按钮后变为蓝色：
点击红色按钮后变为红色：
Program 2：
Balls.java 代码部分
package Lab9;
class Balls { //定义圆的颜色 type，1 表示蓝色，2 表示红色 int color=0; //定义圆的位置 int locate=50;
//注册监听 jb1.addActionListener(mp); jb1.setActionCommand("蓝色"); jb2.addActionListener(mp); jb2.setActionCommand("红色"); jb3.addActionListener(mp); jb3.setActionCommand("加圆");