import java.awt.*;
import java.awt.event.*;
class Mycanvas extends Canvas
{
int x,y,r;
Mycanvas()
{
setBackground(Color.cyan);
}
public void setX(int x)
{
this.x=x;
}
public void setY(int y)
{
this.y=y;
}
public void setR(int r)
{
this.r=r;
}
public void paint(Graphics g)
{
g.drawOval(x, y, 2*r, 2*r);
}
}
class WindowCanvas extends Frame implements ActionListener
{
Mycanvas canvas;
TextField inputR,inputX,inputY;
Button b;
WindowCanvas()
{
canvas=new Mycanvas();
inputR=new TextField(5);
inputX=new TextField(4);
inputY=new TextField(4);
Panel pNorth=new Panel();
Panel pSouth=new Panel();
pNorth.add(new Label("circle's coordinate:"));
pNorth.add(inputX);
pNorth.add(inputY);
pSouth.add(new Label("circle's radius:"));
pSouth.add(inputR);
b=new Button("Enter");
b.addActionListener(this);
pSouth.add(b);
add(canvas,BorderLayout.CENTER);
add(pNorth,BorderLayout.NORTH);
add(pSouth,BorderLayout.SOUTH);
setBounds(100,100,300,200);
setVisible(true);
addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{
System.exit(0);
}
});
}
}
public void actionPerformed(ActionEvent e)
{
int x,y,r;
try{
x=Integer.parseInt(inputX.getText());
y=Integer.parseInt(inputY.getText());
r=Integer.parseInt(inputR.getText());
canvas.setX(x);
canvas.setY(y);
canvas.setR(r);
canvas.repaint();
}
catch(NumberFormatException ee)
{
x=0;y=0;r=0;
}
}
public class p159{
public void main(String args[])
{
new WindowCanvas();
}
}
import java.awt.event.*;
class Mycanvas extends Canvas
{
int x,y,r;
Mycanvas()
{
setBackground(Color.cyan);
}
public void setX(int x)
{
this.x=x;
}
public void setY(int y)
{
this.y=y;
}
public void setR(int r)
{
this.r=r;
}
public void paint(Graphics g)
{
g.drawOval(x, y, 2*r, 2*r);
}
}
class WindowCanvas extends Frame implements ActionListener
{
Mycanvas canvas;
TextField inputR,inputX,inputY;
Button b;
WindowCanvas()
{
canvas=new Mycanvas();
inputR=new TextField(5);
inputX=new TextField(4);
inputY=new TextField(4);
Panel pNorth=new Panel();
Panel pSouth=new Panel();
pNorth.add(new Label("circle's coordinate:"));
pNorth.add(inputX);
pNorth.add(inputY);
pSouth.add(new Label("circle's radius:"));
pSouth.add(inputR);
b=new Button("Enter");
b.addActionListener(this);
pSouth.add(b);
add(canvas,BorderLayout.CENTER);
add(pNorth,BorderLayout.NORTH);
add(pSouth,BorderLayout.SOUTH);
setBounds(100,100,300,200);
setVisible(true);
addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{
System.exit(0);
}
});
}
}
public void actionPerformed(ActionEvent e)
{
int x,y,r;
try{
x=Integer.parseInt(inputX.getText());
y=Integer.parseInt(inputY.getText());
r=Integer.parseInt(inputR.getText());
canvas.setX(x);
canvas.setY(y);
canvas.setR(r);
canvas.repaint();
}
catch(NumberFormatException ee)
{
x=0;y=0;r=0;
}
}
public class p159{
public void main(String args[])
{
new WindowCanvas();
}
}
import java.awt.*;
import java.awt.event.*;
class Mycanvas extends Canvas
{
int x,y,r;
Mycanvas()
{
setBackground(Color.cyan);
}
public void setX(int x)
{
this.x=x;
}
public void setY(int y)
{
this.y=y;
}
public void setR(int r)
{
this.r=r;
}
public void paint(Graphics g)
{
g.drawOval(x, y, 2*r, 2*r);
}
}
class WindowCanvas extends Frame implements ActionListener
{
Mycanvas canvas;
TextField inputR,inputX,inputY;
Button b;
WindowCanvas()
{
canvas=new Mycanvas();
inputR=new TextField(5);
inputX=new TextField(4);
inputY=new TextField(4);
Panel pNorth=new Panel();
Panel pSouth=new Panel();
pNorth.add(new Label("circle's coordinate:"));
pNorth.add(inputX);
pNorth.add(inputY);
pSouth.add(new Label("circle's radius:"));
pSouth.add(inputR);
b=new Button("Enter");
b.addActionListener(this);
pSouth.add(b);
add(canvas,BorderLayout.CENTER);
add(pNorth,BorderLayout.NORTH);
add(pSouth,BorderLayout.SOUTH);
setBounds(100,100,300,200);
setVisible(true);
addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{
System.exit(0);
}
});
}
}
public void actionPerformed(ActionEvent e)
{
int x,y,r;
try{
x=Integer.parseInt(inputX.getText());
y=Integer.parseInt(inputY.getText());
r=Integer.parseInt(inputR.getText());
canvas.setX(x);
canvas.setY(y);
canvas.setR(r);
canvas.repaint();
}
catch(NumberFormatException ee)
{
x=0;y=0;r=0;
}
}
public class p159{
public void main(String args[])
{
new WindowCanvas();
}
}
public void main(String args[]) //这里是public static void main(String args[])
{
new WindowCanvas();
}
}
package practice;import java.awt.*;
import java.awt.event.*;class Mycanvas extends Canvas {
private static final long serialVersionUID = 1L;
int x, y, r; Mycanvas() {
setBackground(Color.cyan);
} public void setX(int x) {
this.x = x;
} public void setY(int y) {
this.y = y;
} public void setR(int r) {
this.r = r;
} public void paint(Graphics g) {
g.drawOval(x, y, 2 * r, 2 * r);
}
}public class WindowCanvas extends Frame implements ActionListener { private static final long serialVersionUID = 1L;
Mycanvas canvas;
TextField inputR, inputX, inputY;
Button b; WindowCanvas() {
canvas = new Mycanvas();
inputR = new TextField(5);
inputX = new TextField(4);
inputY = new TextField(4);
Panel pNorth = new Panel();
Panel pSouth = new Panel();
pNorth.add(new Label("circle's coordinate:"));
pNorth.add(inputX);
pNorth.add(inputY);
pSouth.add(new Label("circle's radius:"));
pSouth.add(inputR);
b = new Button("Enter");
b.addActionListener(this);
pSouth.add(b);
add(canvas, BorderLayout.CENTER);
add(pNorth, BorderLayout.NORTH);
add(pSouth, BorderLayout.SOUTH);
setBounds(100, 100, 300, 200);
setVisible(true);
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
} public void actionPerformed(ActionEvent e) {
int x, y, r;
try {
x = Integer.parseInt(inputX.getText());
y = Integer.parseInt(inputY.getText());
r = Integer.parseInt(inputR.getText());
canvas.setX(x);
canvas.setY(y);
canvas.setR(r);
canvas.repaint();
} catch (NumberFormatException ee) {
x = 0;
y = 0;
r = 0;
}
} public static class p159 {
public static void main(String args[]) {
new WindowCanvas();
}
}
}
P159.java:62: 需要 "class" 或 "interface"
public void actionPerformed(ActionEvent e)
^
1 错误怎么编译出这个结果了,是包没导入吗?
import java.awt.*;
import java.awt.event.*;class Mycanvas extends Canvas
{
int x,y,r;
Mycanvas(){
setBackground(Color.cyan);
}
public void setX(int x){
this.x=x;
}
public void setY(int y){
this.y=y;
}
public void setR(int r){
this.r=r;
}
public void paint(Graphics g){
g.drawOval(x, y, 2*r, 2*r);
}
}class WindowCanvas extends Frame implements ActionListener
{
Mycanvas canvas;
TextField inputR,inputX,inputY;
Button b;
WindowCanvas(){
canvas=new Mycanvas();
inputR=new TextField(5);
inputX=new TextField(4);
inputY=new TextField(4);
Panel pNorth=new Panel();
Panel pSouth=new Panel();
pNorth.add(new Label("circle's coordinate:"));
pNorth.add(inputX);
pNorth.add(inputY);
pSouth.add(new Label("circle's radius:"));
pSouth.add(inputR);
b=new Button("Enter");
b.addActionListener(this);
pSouth.add(b);
add(canvas,BorderLayout.CENTER);
add(pNorth,BorderLayout.NORTH);
add(pSouth,BorderLayout.SOUTH);
setBounds(100,100,300,200);
setVisible(true);
addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e){
System.exit(0);
}
});
} public void actionPerformed(ActionEvent e){
int x,y,r;
try{
x=Integer.parseInt(inputX.getText());
y=Integer.parseInt(inputY.getText());
r=Integer.parseInt(inputR.getText());
canvas.setX(x);
canvas.setY(y);
canvas.setR(r);
canvas.repaint();
}catch(NumberFormatException ee){
x=0;y=0;r=0;
}
}
}
public class TestPy{
public static void main (String args[]){
new WindowCanvas();
}
}
import java.awt.event.*;
/**
* 作者:李 世贵
* JDK: 1.6
* 来源: http://blog.csdn.net/lishigui
* 欢迎转接,请保留作者和来源,谢谢!
* 2009-4-23 下午12:44:42
*/
class Mycanvas extends Canvas {
int x, y, r; Mycanvas() {
setBackground(Color.cyan);
} public void setX(int x) {
this.x = x;
} public void setY(int y) {
this.y = y;
} public void setR(int r) {
this.r = r;
} public void paint(Graphics g) {
g.drawOval(x, y, 2 * r, 2 * r);
}
}public class WindowCanvas extends Frame implements ActionListener {
Mycanvas canvas;
TextField inputR, inputX, inputY;
Button b; WindowCanvas() {
canvas = new Mycanvas();
inputR = new TextField(5);
inputX = new TextField(4);
inputY = new TextField(4);
Panel pNorth = new Panel();
Panel pSouth = new Panel();
pNorth.add(new Label("circle's coordinate:"));
pNorth.add(inputX);
pNorth.add(inputY);
pSouth.add(new Label("circle's radius:"));
pSouth.add(inputR);
b = new Button("Enter");
b.addActionListener(this);
pSouth.add(b);
add(canvas, BorderLayout.CENTER);
add(pNorth, BorderLayout.NORTH);
add(pSouth, BorderLayout.SOUTH);
setBounds(100, 100, 300, 200);
setVisible(true);
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
} public void actionPerformed(ActionEvent e) {
int x, y, r;
try {
x = Integer.parseInt(inputX.getText());
y = Integer.parseInt(inputY.getText());
r = Integer.parseInt(inputR.getText());
canvas.setX(x);
canvas.setY(y);
canvas.setR(r);
canvas.repaint();
} catch (NumberFormatException ee) {
x = 0;
y = 0;
r = 0;
}
} public static void main(String args[]) {
new WindowCanvas();
}}
import java.awt.event.*;
class Mycanvas extends Canvas
{
int x,y,r;
Mycanvas()
{ setBackground(Color.cyan); }
public void setX(int x) {this.x=x;}
public void setY(int y) { this.y=y; }
public void setR(int r) {this.r=r; }
public void paint(Graphics g) { g.drawOval(x, y, 2*r, 2*r); }
}
class WindowCanvas extends Frame implements ActionListener
{
Mycanvas canvas;
TextField inputR,inputX,inputY;
Button b;
WindowCanvas()
{
canvas=new Mycanvas();
inputR=new TextField(5);
inputX=new TextField(4);
inputY=new TextField(4);
Panel pNorth=new Panel();
Panel pSouth=new Panel();
pNorth.add(new Label("circle's coordinate:"));
pNorth.add(inputX);
pNorth.add(inputY);
pSouth.add(new Label("circle's radius:"));
pSouth.add(inputR);
b=new Button("Enter");
b.addActionListener(this);
pSouth.add(b);
add(canvas,BorderLayout.CENTER);
add(pNorth,BorderLayout.NORTH);
add(pSouth,BorderLayout.SOUTH);
setBounds(100,100,300,200);
setVisible(true);
addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{
System.exit(0);
}
});
}
public void actionPerformed(ActionEvent e)
{
int x,y,r;
try{
x=Integer.parseInt(inputX.getText());
y=Integer.parseInt(inputY.getText());
r=Integer.parseInt(inputR.getText());
canvas.setX(x);
canvas.setY(y);
canvas.setR(r);
canvas.repaint(); }
catch(NumberFormatException ee)
{x=0;y=0;r=0; }
}
}
public class P159{
public static void main(String args[])
{ new WindowCanvas(); }
}
//可以了