Question

编译器显示的错误是： -

＆＃34; Slot_Machine不是抽象的，并且不会覆盖java.awt.event.ActionListener中的抽象方法actionPerformed（java.awt.event.ActionEvent）。＆＃34;

该计划是： -

import java.awt.*;
import java.awt.event.*;
import java.applet.*;
public class Slot_Machine extends Applet implements ActionListener
{
public void init()
{
Button B1 = new Button("Start");
B1.addActionListener(this);
add(B1);
}

public void paint(Graphics g)
{
int mm = 5000;
int x1[] = {245,210,210,245,315,350,350,315};
int y1[] = {175,315,385,525,525,385,315,175};
int n1 = x1.length;
int x2[] = {455,420,420,455,525,560,560,525};
int x3[] = {665,630,630,665,735,770,770,735};
g.setColor(Color.red);
g.fillPolygon(x1,y1,n1);
g.fillPolygon(x2,y1,n1);
g.fillPolygon(x3,y1,n1);
int x4[] = {280,245,315};
int y4[] = {210,280,280};
int n4 = x4.length;
int x5[] = {490,455,525};
int x6[] = {700,665,735};
int x7[] = {245,280,315};
int y7[] = {420,490,420};
int n7 = x7.length;
int x8[] = {455,490,525};
int x9[] = {665,700,735};
g.setColor(Color.green);
g.fillPolygon(x4,y4,n4);
g.fillPolygon(x5,y4,n4);
g.fillPolygon(x6,y4,n4);
g.fillPolygon(x7,y7,n7);
g.fillPolygon(x8,y7,n7);
g.fillPolygon(x9,y7,n7);
g.setColor(Color.yellow);
g.fillRect(245,315,70,70);
g.fillRect(455,315,70,70);
g.fillRect(665,315,70,70);
Font F1 = new Font ("courier new", Font.BOLD,20);
g.setFont(F1);
Button B1 = new Button ("Start");
}
}

Answer 1

您已将该类标记为实现ActionListener接口，但您根本没有实际实现它。

您必须在班级中使用此方法

public void actionPerformed(ActionEvent e) {

}

参考：http://www.tutorialspoint.com/awt/awt_action_listener.htm

Answer 2

如果它应该是ActionListener，那么您需要实现ActionListener接口。否则，不要说它是ActionListener

执行：

void actionPerformed(java.awt.event.ActionEvent) {
  // stuff
}

或

public class Slot_Machine extends Applet

在下面的程序中该怎么做才能消除下面给出的编译器错误并使程序最好地工作？

2 个答案: