JButton和ActionListener导致许多运行时错误

Question

所以我正在尝试使用Eclipse和JSwing制作Conway的《人生游戏》的一个版本，我的问题是，当我试图启动代码以运行一代时，它反而会产生大量的运行时错误。当我试图按下第一个JButton时，问题就会出现，我目前正在使用它作为下一代模拟的启动按钮。Cell类只是一组setter和getter，用于它的当前状态和它在按钮阵列中的位置。当我按下第一个按钮时发生的错误列表在代码下面

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();
}
}
}

下面是当我按下的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)

Answer 1

在setnewstates()中，首先设置k=0，然后在while循环中执行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;

只是想一想：使用一维数组会让你的生活变得非常困难。生活是在二维网格上进行的(你有50x50(，所以我建议你用二维阵列[50][50]进行实验。