Question

private class CalculateButtonHandler implements ActionListener{

    public CalculateButtonHandler(JTextField initialAmmount, JTextField yearsToMaturity, JTextField interestRate){
        double endingBalance;
        String text = interestRate.getText();
        int interestRateInt = Integer.parseInt(text);

        String text1 = yearsToMaturity.getText();
        int yearsToMaturityInt = Integer.parseInt(text);

        String text2 = initialAmount.getText();
        int initialAmountInt = Integer.parseInt(text);

        endingBalance = initialAmountInt * Math.pow((1 + interestRateInt/1), 1 *           yearsToMaturityInt);
    }

    public void actionPerformed(ActionEvent e){
    }
}

当前运行时错误：线程＆＃34; main＆＃34;中的例外情况java.lang.NumberFormatException：对于输入字符串：＆＃34;＆＃34;

我假设发生运行时错误，因为程序运行时没有输入，并且用户没有机会输入要解析为int的字符串。我无法弄清楚如何检查这一点。

Answer 1

处理按钮单击事件的代码需要在actionPerformed方法中，而不是在构造函数中。

private class CalculateButtonHandler implements ActionListener{

    private final JTextField interestRate;
    private final JTextField yearsToMaturity;
    private final JTextField interestRate;

    public CalculateButtonHandler(JTextField initialAmmount, JTextField     yearsToMaturity, JTextField interestRate) {
        this.initialAmmount = initialAmmount;
        this.yearsToMaturity = yearsToMaturity;
        this.interestRate = interestRate;
    }

    public void actionPerformed(ActionEvent e){
       double endingBalance;
       String text = interestRate.getText();
       int interestRateInt = Integer.parseInt(text);

       String text1 = yearsToMaturity.getText();
       int yearsToMaturityInt = Integer.parseInt(text);

       String text2 = initialAmount.getText();
       int initialAmountInt = Integer.parseInt(text);

       endingBalance = initialAmountInt * Math.pow((1 + interestRateInt/1), 1 *           yearsToMaturityInt);
   }
}

在用户输入之前检查空的JTextField

1 个答案: