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java - JButton 和 ActionListener 导致许多运行时错误

问题描述

所以我正在尝试使用 Eclipse 和 JSwing 制作康威生命游戏的一个版本，我的问题是当我尝试启动代码以运行一代时，它会产生大量运行时错误当我尝试按下我目前用作下一代模拟的开始按钮的第一个 JButton。Cell 类只是其当前状态及其在按钮数组中的位置的一组 setter 和 getter，当我按下第一个按钮时发生的错误列表位于代码下方

public class MainPage extends JFrame implements ActionListener{

JButton[] screen = new JButton[2500]; 
JButton start = new JButton("Start");
Cell[] cells = new Cell[2500];
int select = 0;

public static void main(String args[]) {

    new MainPage();

}

public MainPage() {
    super("The Game Of Life");
    int k = 0;
    while (k < 2500) {
        screen[k] = new JButton("");
        screen[k].setBackground(Color.BLACK);
        cells[k] = new Cell(k);
        cells[k].setState(0);
        k++;
    }

    Container surface = this.getContentPane();
    surface.setLayout(new GridLayout(50,50));

    // k == row j == col
    for (int i = 0; i < 2500; i++) {

           int finalI = i; // no final modifier
            surface.add(screen[i]);

            screen[i].addActionListener(e -> {


                Color color = screen[finalI].getBackground();
                if (color == Color.BLACK)
                {
                    screen[finalI].setBackground(Color.WHITE);
                    cells[finalI].setState(1);
                }
                else {
                    screen[finalI].setBackground(Color.BLACK);
                    cells[finalI].setState(0);
                }

            });
            screen[0].addActionListener(this);

    }

    this.pack();
    this.setVisible(true);


}
public void setnewstates() {
    int k = 51;
    int screensize = 50;

    while (k < 2500 || k > 50 || k % 50 != 0 || (k + 1) % 50 != 0) // avoid borders for now
    {
        int neighbors = 0;
        int state = cells[k].getState();
        neighbors = cells[k - 1].getState() + neighbors; // check neighbors
        neighbors = cells[k + 1].getState() + neighbors;
        neighbors = cells[k + screensize].getState() + neighbors;
        neighbors = cells[k - screensize].getState() + neighbors;
        neighbors = cells[k + screensize + 1].getState() + neighbors;
        neighbors = cells[k + screensize - 1].getState() + neighbors;
        neighbors = cells[k - screensize - 1].getState() + neighbors;
        neighbors = cells[k - screensize + 1].getState() + neighbors;   

        if (state == 1) {
            if (neighbors < 2)
            {
                cells[k].setState(0);
                screen[k].setBackground(Color.BLACK);
            }
            if (neighbors > 3)
            {
                cells[k].setState(0);
                screen[k].setBackground(Color.BLACK);
            }
        }
        else if (state == 0) {
            if (neighbors == 3)
            {
                cells[k].setState(1);
                screen[k].setBackground(Color.WHITE);
            }
        }
    k++;
    }
}

public void actionPerformed(ActionEvent e) {
    if (e.getSource() == screen[0])
    {
        setnewstates();
    }
}
}

这是我按下第一个按钮时发生的错误

Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: -1
at MainPage.setnewstates(MainPage.java:72)
at MainPage.actionPerformed(MainPage.java:106)
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)

标签： javaarraysswingjbuttonindexoutofboundsexception

解决方案

在setnewstates()中，首先设置 k=0，然后在 while 循环中做的第一件事就是引用cells[k - screensize - 1]

例如：

int neighbors = 0;
int state = cells[k].getState();

if (k > 0) neighbors = cells[k - 1].getState() + neighbors; // check neighbors
if (k < 2500) neighbors = cells[k + 1].getState() + neighbors;
if (k + screensize < 2500) neighbors = cells[k + screensize].getState() + neighbors;

只是一个想法：使用一维数组让你的生活变得非常困难。生活是在二维网格上播放的（你有 50x50），所以我建议你尝试使用二维数组 [50][50]。

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