java代码绘制形状 用Java编写图案

java 绘图程序

我基于你原来画图的方法，添加了事件触发的命令b[j].setActionCommand("b" + j);否则你不能在事件响应处理的方法中使用e.getActionCommand()，而且字符串的比较用equals方法比较好。现在可以运行了，你可以看一下：

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import java.applet.Applet;

import java.awt.*;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

public class drawing extends Applet implements ActionListener {

Button b[] = new Button[5];

String fontname = "仿宋_GB2312";

int style = Font.PLAIN;

int size = 24;

int index = 0;

Font myfont;

public void init() {

setSize(700,700);

myfont = new Font(fontname, style, size);

b[0] = new Button("扇形");

b[1] = new Button("圆形");

b[2] = new Button("三角形");

b[3] = new Button("长方形");

b[4] = new Button("椭圆形");

for (int j = 0; j b.length; j++) {

b[j].setBounds(10, 10, 50, 20);

b[j].addActionListener(this);

b[j].setActionCommand("b" + j);

add(b[j]);

}

}

public void actionPerformed(ActionEvent e) {

if (e.getActionCommand().equals("b0")) {

index = 0;

repaint();

}

if (e.getActionCommand().equals("b1")) {

index = 1;

repaint();

}

if (e.getActionCommand().equals("b2")) {

index = 2;

repaint();

}

if (e.getActionCommand().equals("b3")) {

index = 3;

repaint();

}

if (e.getActionCommand().equals("b4")) {

index = 4;

repaint();

}

}

public void paint(Graphics g) {

switch (index) {

case 0:

g.fillArc(0, 60, 80, 60, 30, 120);

break;

case 1:

g.drawOval( 300, 50, 60, 60);

break;

case 2:

Polygon filledPolygon = new Polygon();

filledPolygon.addPoint(380, 50);

filledPolygon.addPoint(380, 110);

filledPolygon.addPoint(450, 90);

g.drawPolygon(filledPolygon);

break;

case 3:

g.drawRect( 200, 50, 80, 60);

break;

case 4:

g.drawOval(100, 50, 80, 60);

break;

default:

g.fillArc(0, 60, 80, 60, 30, 120);

break;

}

}

/*

* public void paint(Graphics g) { g.fillArc( 0, 60, 80, 60, 30, 120);

* //绘制扇形 g.drawOval( 100, 50, 80, 60); g.drawRect( 200, 50, 80, 60);

* g.drawOval( 300, 50, 60, 60); Polygon filledPolygon=new Polygon();

* filledPolygon.addPoint(380,50); filledPolygon.addPoint(380,110);

* filledPolygon.addPoint(450,90); g.drawPolygon(filledPolygon); }

*/

}

关于java中画图形的paint方法

应该先调用父类的paint，即super.paint(g)，不过最好的方法还是继承出一个JPanel的子类，然后重载它的paint方法，然后把这个子类的实例增加到JFrame的容器里

如何用Java编写一个绘制图形的小程序？

import java.awt.*;

import java.awt.event.*;

import java.awt.geom.*;

import javax.swing.*;

//不规则图形的绘制

public class IrregularShapeDemo extends JFrame {

GeneralPath gPath= new GeneralPath(); //GeneralPath对象实例

Point aPoint;

//构造函数

public IrregularShapeDemo() {

super("不规则图形的绘制"); //调用父类构造函数

enableEvents(AWTEvent.MOUSE_EVENT_MASK|AWTEvent.MOUSE_MOTION_EVENT_MASK); //允许事件

setSize(300, 200); //设置窗口尺寸

setVisible(true); //设置窗口可视

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //关闭窗口时退出程序

}

public void paint(Graphics g) { //重载窗口组件的paint()方法

Graphics2D g2D = (Graphics2D)g;//获取图形环境

g2D.draw(gPath); //绘制路径

}

public static void main(String[] args) {

new IrregularShapeDemo();

}

protected void processMouseEvent(MouseEvent e) { //鼠标事件处理

if(e.getID() == MouseEvent.MOUSE_PRESSED) {

aPoint = e.getPoint(); //得到当前鼠标点

gPath = new GeneralPath(); //重新实例化GeneralPath对象

gPath.moveTo(aPoint.x,aPoint.y); //设置路径点

}

}

protected void processMouseMotionEvent(MouseEvent e) { //鼠标运动事件处理

if(e.getID() == MouseEvent.MOUSE_DRAGGED) {

aPoint = e.getPoint(); //得到当前鼠标点

gPath.lineTo(aPoint.x, aPoint.y); //设置路径

gPath.moveTo(aPoint.x, aPoint.y);

repaint(); //重绘组件

}

}

}

根据以下任务要求，编写Java应用程序？

按照题目要求编写的Java程序如下

注意 请使用你的真实姓名和班级替换Test类中

创建Student对象stu时用的"张三"和"20计算机应用01班"

import java.util.Scanner;

class Student{

private String name,classname;

private int starnum,scorenum;

private int[] scores;

public void setStarNum(int n){

this.starnum=n;

}

public Student(String name,String classname,int scorenum){

this.name=name;

this.classname=classname;

this.scorenum=scorenum;

}

public String getName(){

return this.name;

}

public void printStar(){

for(int i=0;istarnum;i++){

for(int j=0;j2*i+1;j++){

System.out.print("*");

}

System.out.println();

}

}

public void setScore(){

Scanner sc=new Scanner(System.in);

scores=new int[scorenum];

System.out.print("请输入各科成绩：");

for(int i=0;iscorenum;i++){

scores[i]=sc.nextInt();

}

}

public void showInfo(){

System.out.print(name+"同学，你所在的班级是"+classname+"，你各科考试成绩分别为：");

for(int i=0;iscorenum;i++){

if(i==scorenum-1)

System.out.print(scores[i]);

else

System.out.print(scores[i]+"，");

}

System.out.println();

}

public float getAvg(){

float sum=0;

for(int i=0;iscorenum;i++){

sum=sum+scores[i];

}

return sum/scorenum;

}

}

public class Test{

public static void main(String[] args){

Student stu=new Student("张三","20计算机应用01班",5);

stu.setStarNum(4);

stu.printStar();

stu.setScore();

stu.showInfo();

if(stu.getAvg()60){

System.out.println(stu.getName()+"是不合格学生");

}else{

System.out.println(stu.getName()+"是个合格学生");

}

}

}