Java JMenuItem问题。我有五个。其中一个编译起来没有问题。其他的都是相同的,但是他们拒绝编译
由于某些原因,我无法在Eclipse中编译此文件。“退出”菜单项有效,其他菜单项无效。为什么呢Java JMenuItem问题。我有五个。其中一个编译起来没有问题。其他的都是相同的,但是他们拒绝编译,java,swing,action,menuitem,Java,Swing,Action,Menuitem,由于某些原因,我无法在Eclipse中编译此文件。“退出”菜单项有效,其他菜单项无效。为什么呢 import java.awt.*; import java.awt.event.*; import javax.swing.*; public class GUI{ private JFrame frame; public GUI(){ makeFrame(); } //This method makes the overall GUI and adds panels, labels
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class GUI{
private JFrame frame;
public GUI(){
makeFrame();
}
//This method makes the overall GUI and adds panels, labels,
//buttons, and everything else to the GUI.
public void makeFrame(){
frame = new JFrame("Tower Defense");
Container contentPane = frame.getContentPane();
makeMenus();
JButton shootButton = new JButton("Shoot");
contentPane.add(shootButton);
frame.pack();
frame.setVisible(true);
}
//This method makes the menu and all of the items contained
//in the menu which is then called by the makeFrame() method.
//I also add the menuItem's various ActionLiteners here.
public void makeMenus(){
JMenuBar menubar = new JMenuBar();
frame.setJMenuBar(menubar);
JMenu fileMenu = new JMenu("File");
JMenu actionsMenu = new JMenu("Actions");
JMenu buildMenu = new JMenu("Build");
menubar.add(fileMenu);
menubar.add(actionsMenu);
menubar.add(buildMenu);
JMenuItem sellItem = new JMenuItem("Sell");
JMenuItem quitItem = new JMenuItem("Quit");
JMenuItem turretsItem = new JMenuItem("Turrets");
JMenuItem minesItem = new JMenuItem("Mines");
JMenuItem workersItem = new JMenuItem("Workers");
quitItem.addActionListener(new QuitActionListener());
sellItem.addActionListener(new SellActionListener());
turretsItem.addActionListener(new TurretsActionListener());
minesItem.addActionListener(new MinesActionListener());
workersItem.addActionListener(new WorkersActionListener());
fileMenu.add(quitItem);
actionsMenu.add(sellItem);
buildMenu.add(turretsItem);
buildMenu.add(minesItem);
buildMenu.add(workersItem);
}
//Main method. It creates a new GUI.
public static void main(String args []){
GUI gui = new GUI();
}
class QuitActionListener implements ActionListener{
public void actionPerformed(ActionEvent e){
System.exit(0);
}
}
class SellActionListener{
public void actionPerformed(ActionEvent e){
System.exit(0);
}
}
class TurretsActionListener{
public void actionPerformed(ActionEvent e){
System.exit(0);
}
}
class MinesActionListener{
public void actionPerformed(ActionEvent e){
System.exit(0);
}
}
class WorkersActionListener{
public void actionPerformed(ActionEvent e){
System.exit(0);
}
}
class ShootActionListener{
public void actionPerformed(ActionEvent e){
System.exit(0);
}
}
}
它不是编译,因为您提供的操作侦听器(例如
SellActionListener
)没有实现ActionListener
。方法addActionListener
需要一个实现ActionListener
的对象
这:
需要做到这一点:
class SellActionListener implements ActionListener{
public void actionPerformed(ActionEvent e){
System.exit(0);
}
}
(与其他动作侦听器一起)
为子孙后代
这些类型的错误通常可以从编译器的反馈中找出。当eclipse说存在编译错误时,您应该能够看到错误的详细信息。我猜它可能会说“类SellActionListener没有实现接口ActionListener”(或者类似的话)。如果你用谷歌搜索该错误消息,你可能会比等待别人回答你的特定问题更快地找到答案。或者使用testing for sources Object obj=e.getSource()将所有ActionListener放在一个类中;或者调用java.swing.Action+1@mKorbel-1表示一个大ActionListener,+1表示Action(假设每个项目一个;-)
class SellActionListener implements ActionListener{
public void actionPerformed(ActionEvent e){
System.exit(0);
}
}