Question

我收到了这个错误，但我似乎无法找到想要它的原因。它说错误在我初始化变量bet的行上。如果我删除该行并Integer.parseInt(betTextFieldAmount)，则说明错误是在初始化时。

public class RollTheDice extends JFrame implements ActionListener {

    JButton roll = new JButton("Roll the Dice");
    JButton bet1 = new JButton("5$");
    JButton bet2 = new JButton("10$");
    JButton bet3 = new JButton("25$");
    JButton bet4 = new JButton("50$");
    JButton bet5 = new JButton("100$");

    JTextField betTextField = new JTextField(5);
    String betTextFieldAmount = betTextField.getText();
    int bet = Integer.parseInt(betTextFieldAmount);

    int money = 100;

    JLabel currentBet = new JLabel();
    JLabel currentMoney = new JLabel("Your money: " + money + "$");

    int myDice = new Random().nextInt(12) + 1;
    int AIDice = new Random().nextInt(12) + 1;

    public static void RollTheDice() {
        int myDice = new Random().nextInt(12) + 1;
        int AIDice = new Random().nextInt(12) + 1;
    }

    public RollTheDice() {
        setLayout(new FlowLayout());

        add(currentMoney);

        add(bet1);
        bet1.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                if (money < 5) {
                    JOptionPane.showMessageDialog(null, "Not enough money!");
                } else {
                    money -= 5;
                    bet +=5;
                }
                currentMoney.setText(money + "$");
            }           
        });

        add(bet2);
        bet2.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                if (money < 10) {
                    JOptionPane.showMessageDialog(null, "Not enough money!");
                } else {
                    money -= 10;
                    bet +=10;
                }
                currentMoney.setText(money + "$");
            }           
        });

        add(bet3);
        bet3.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                if (money < 25) {
                    JOptionPane.showMessageDialog(null, "Not enough money!");
                } else {
                    money -= 25;
                    bet +=25;
                }
                currentMoney.setText(money + "$");
            }           
        });

        add(bet4);
        bet4.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                if (money < 50) {
                    JOptionPane.showMessageDialog(null, "Not enough money!");
                } else {
                    money -= 50;
                    bet +=50;
                }
                currentMoney.setText(money + "$");
            }           
        });

        add(bet5);
        bet5.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                if (money < 100) {
                    JOptionPane.showMessageDialog(null, "Not enough money!");
                } else {
                    money -= 100;
                    bet +=100;
                }
                currentMoney.setText(money + "$");
            }           
        });

        add(betTextField);
        betTextField.setEditable(false);
        add(roll);
        roll.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                if (myDice > AIDice) {
                    money += bet;
                    JOptionPane.showMessageDialog(null, "You won " + bet + "$");
                } else {
                    JOptionPane.showMessageDialog(null, "You lost " + bet + "$");
                }
                currentMoney.setText(money + "$");
                RollTheDice();
            }           
        });
    }

    @Override
    public void actionPerformed(ActionEvent arg0) {
        // TODO Auto-generated method stub

    }
}

Answer 1

Integer.parseInt(betTextFieldAmount)导致此错误检查betTextFieldAmount以查看它是否具有有效的整数值确保betTextFieldAmount不应为null，或者在开头或结尾包含任何特殊字符或空格。

Answer 2

这是由Integer.parseInt(betTextFieldAmount);的值不是有效整数引起的，因此当您尝试使用parseInt转换它时会抛出异常。

如果发生这种情况，您应该使用try...catch声明围绕var a string func f() { print(a) } func hello() { a = "hello, world" go f() }来电，并向用户显示相应的错误消息。

更好的是，尝试通过限制可以在字段中输入的字符来防止用户首先输入非数字值，并添加空白检查以捕获在字段中未输入任何值的情况。

Answer 3

尝试验证betTextField.getText（）是否为null。我假设你的字段没有值，所以getText将返回null并且解析将失败

无法解析Integer.ParseInt抛出的java.lang.NumberFormatException

3 个答案: