Question

有源代码不允许编辑，我需要添加一个稍微修改它的方面类。

以下是我所做的课程：

package ext;

import java.awt.event.ActionEvent;
import javax.swing.*;
import battleship.*;

 public privileged aspect AddStrategy {


    JButton playButton1 = new JButton("Play");

    after(BattleshipDialog dialog): this(dialog) && execution(JPanel BattleshipDialog.makeControlPane()){

        dialog.playButton.setText("Practice");
        JPanel buttons = (JPanel) dialog.playButton.getParent();
        buttons.add(playButton1);
        playButton1.setFocusPainted(false);
        playButton1.addActionListener(this::playButton1Clicked);
    }

    BattleshipDialog bd;
    public void playButton1Clicked(ActionEvent event) {
        bd.startNewGame();
    }
}

我能够成功地将原始按钮“Play”重命名为“练习”。每当我点击“练习”按钮时，它都具有重新启动游戏的原始功能，并且工作正常。

但是，当我尝试使用新创建的按钮“Play”模仿该功能时，控制台会显示一堆错误，所有错误都表示blahblahblah（UnknownSource）。

我想我得到了这个问题，因为我需要扩充相同的“对话框”，我正在尝试使用“对话框”和“bd”。但是，我尝试了各种方法使它们使用相同的对话框，但没有一个工作。

TL;博士试图让2个按钮做同样的事情，但只有1个按钮执行它，而另一个按钮向控制台抛出一堆“未知来源”错误。

我不确定它是否会有所帮助，但这是来自BattleshipDialog.java类的相关源代码：

public void playButtonClicked(ActionEvent event) {
    if (isGameOver()) {
        startNewGame();
    } else {
        if (JOptionPane.showConfirmDialog(BattleshipDialog.this, 
            "Play a new game?", "Battleship", JOptionPane.YES_NO_OPTION)
            == JOptionPane.YES_OPTION) {
            startNewGame();
        }
    }
}

/** Start a new game. This will terminate the current play and
 * start a new play. */
private void startNewGame() {
    msgBar.setText("Shots: 0");
    board.reset();
    placeShips();
    repaint();
}

编辑：以下是根据请求的错误消息：

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at ext.AddStrategy.playButton1Clicked(AddStrategy.aj:30)
    at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
    at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
    at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
    at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
    at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
    at java.awt.Component.processMouseEvent(Unknown Source)
    at javax.swing.JComponent.processMouseEvent(Unknown Source)
    at java.awt.Component.processEvent(Unknown Source)
    at java.awt.Container.processEvent(Unknown Source)
    at java.awt.Component.dispatchEventImpl(Unknown Source)
    at java.awt.Container.dispatchEventImpl(Unknown Source)
    at java.awt.Component.dispatchEvent(Unknown Source)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
    at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
    at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
    at java.awt.Container.dispatchEventImpl(Unknown Source)
    at java.awt.Window.dispatchEventImpl(Unknown Source)
    at java.awt.Component.dispatchEvent(Unknown Source)
    at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
    at java.awt.EventQueue.access$500(Unknown Source)
    at java.awt.EventQueue$3.run(Unknown Source)
    at java.awt.EventQueue$3.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
    at java.awt.EventQueue$4.run(Unknown Source)
    at java.awt.EventQueue$4.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
    at java.awt.EventQueue.dispatchEvent(Unknown Source)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.run(Unknown Source)

事件处理程序，新按钮不起作用

0 个答案: