即时作出一个Java卡片游戏的任务,我已经遇到了问题。Java摇摆卡游戏错误
下面的代码是在不同的类。
cgp class。
private DisplayableDeck deck = new DisplayableDeck("b1fv.png");
DisplayableCard[] cards = new DisplayableCard[10];
private Thread[] theThreads = new Thread[2];
private int[] players = new int[2];
private Deck D = new Deck();
int count = 0;
Graphics g;
CardGamePanel()
{
D.buildDeck();
for(int i=0;i<cards.length;i++)
{
Random r = new Random();
int num1 =r.nextInt(52);
cards[i] = new DisplayableCard("1.png",30,30);
}
}
public void go()
{
if(count < 9)
{
cards[count].display(g); //error here
}
count ++;
}
简单的类继承JApplet的
private CardGamePanel cgp;
private JButton btnD = new JButton("Flip");
private Thread repaintThread;
public void init()
{
cgp = new CardGamePanel();
JPanel panel2 = new JPanel();
panel2.add(btnD);
btnD.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
cgp.go();
}
});
add(cgp, BorderLayout.CENTER);
add(panel2, BorderLayout.SOUTH);
setSize(500,500);
}
-
public class DisplayableCard extends Card implements Displayable {
public int x,y;
private Image image;
private String imageFilename = "";
public DisplayableCard(String s,int x,int y) {
imageFilename = s;
this.x =x;
this.y=y;
}
public void display(Graphics g) {
image = new ImageIcon(getClass().getResource(imageFilename)).getImage();
g.drawImage(image, x, y, null); //ERROR HERE
}
游戏引发错误,当我按一下按钮,并调用go()方法。
错误
Exception in thread "AWT-EventQueue-1"
java.lang.NullPointerException
at DisplayableCard.display(DisplayableCard.java:16)
at CardGamePanel.go(CardGamePanel.java:31)
at simple$1.actionPerformed(simple.java:24)
香港专业教育学院写在代码中出现的错误。
不能确定哪一部分是错误的:■任何帮助是非常赞赏:)
堆栈跟踪,请 – bowmore
异常在线程 “AWT-EventQueue的-1” 显示java.lang.NullPointerException \t在DisplayableCard.display(DisplayableCard.java:16) \t在CardGamePanel.go(CardGamePanel.java:31) \t在简单的$ 1.actionPerformed(simple.java:24) – user2291903
你在哪里定义计数?我没有看到你的代码中的任何地方。 – Vinnie