超级新手求助：not abstract and does not override abstract method是什么错误啊？？

[soar_king]

刚学java没几天，照着tutorial的例子想自己编个试试，结果出错：not abstract and does not override abstract method
请各位指点一下我哪里搞错了，代码如下：

import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;

public class Gettry extends Applet implements MouseListener {
private Spot spot = null;
private Color Gold = new Color(255,215,0);

public void init() {
addMouseListener(this);
}

public void paint(Graphics g) {
g.setColor(Color.gray);
g.fillRect(5,5,getSize().width-5,getSize().height-5);
g.setColor(Color.red);
g.drawRect(2,2,getSize().width-2,getSize().height-2);

g.setColor(Gold);
if (spot != null) {
int[] xPoints = {spot.x+7,spot.x+5,spot.x+12,spot.x+4,spot.x+9};
int[] yPoints = {spot.y+4,spot.y+9,spot.y+6,spot.y+6,spot.y+9};
g.fillPolygon(xPoints,yPoints,5);
}
}

public void MouseClicked(MouseEvent event) {
if(spot == null) {
spot = new Spot(0);
}
spot.x = event.getX();
spot.y = event.getY();
repaint();
}
public void mousePressed(MouseEvent event) {}
public void mouseReleased(MouseEvent event) {}
public void mouseEntered(MouseEvent event) {}
public void mouseExited(MouseEvent event) {}
}

[射天狼]

在类前加一个abstract关键字!!
如下:

public abstract class Gettry extends Applet implements MouseListener {
因为你的程序没有包括MouseListener接口里的所有成员函数
或者你把所有的成员函数都加上,就不用此关键字了!!

[minghuitian]

同意上面仁兄的看法.

[Tasia]

你继承一个abstract类之后，你的类要orverride它的全部abstract方法，否则你的类也要声明为abstract。

[soar_king]

加了abstract可以通过了，但是很奇怪啊，我所有的成员函数都加上了，不应该出现这种错误啊。而且我这个和tutorial里的程序基本没变动什么啊，示例程序却不会出错。示例程序如下；

public class ClickMe extends Applet implements MouseListener {
private Spot spot = null;
private static final int RADIUS = 7;

public void init() {
addMouseListener(this);
}

public void paint(Graphics g) {
//draw a black border and a white background
g.setColor(Color.white);
g.fillRect(0, 0, getSize().width - 1, getSize().height - 1);
g.setColor(Color.black);
g.drawRect(0, 0, getSize().width - 1, getSize().height - 1);

//draw the spot
g.setColor(Color.red);
if (spot != null) {
g.fillOval(spot.x - RADIUS, spot.y - RADIUS, RADIUS * 2, RADIUS * 2);
}
}
public void mousePressed(MouseEvent event) {
if (spot == null) {
spot = new Spot(RADIUS);
}
spot.x = event.getX();
spot.y = event.getY();
repaint();
}
public void mouseClicked(MouseEvent event) {}
public void mouseReleased(MouseEvent event) {}
public void mouseEntered(MouseEvent event) {}
public void mouseExited(MouseEvent event) {}
}

[scottwhb]

同意， MouseListener的接口还有其他的成员

[soar_king]

没了啊，我查了javaapidoc，只有这5个嘛

void mouseClicked(MouseEvent e)

void mouseEntered(MouseEvent e)

void mouseExited(MouseEvent e)

void mousePressed(MouseEvent e)

void mouseReleased(MouseEvent e)

[soar_king]

再顺便问一下下面这段程序起的是什么作用？这个this代表什么啊

public void init() {
addMouseListener(this);
}

[programdolt]

你继承一个abstract类之后，你的类要orverride它的全部abstract方法，否则你的类也要声明为abstract。

addMouseListener(this); 注册鼠标监听事件

[lliushine]

是mouseClicked,而不是MouseClicked

[soar_king]

哦，goddamnit。又没注意大小写敏感，谢谢各位的指教