java动作监听器

Question

下面的代码是一个项目的操作侦听器。基本上，我有4个单选按钮，当我点击其中一个时，我希望它改变屏幕上的一个变量。当我运行代码时，它只是将所有值相加。还有其他方法吗

class Calc implements ActionListener
    {
     public void actionPerformed(ActionEvent event)
     {
       double base = 0.00;
       double options;
       double total;

      if (Button25.isSelected());
      {
      base = base + 999.99;
      String base2 = Double.toString(base);
      lblBaseAns.setText(base2);
      }

      if (Button32.isSelected());
      {
        base = base + 1049.99;
        String base2 = Double.toString(base);
        lblBaseAns.setText(base2);
      }

      if (Button35.isSelected());
      {
        base = base + 1099.99;
        String base2 = Double.toString(base);
        lblBaseAns.setText(base2);
      }

      if (Button42.isSelected());
      {
        base = base + 1155.99;
        String base2 = Double.toString(base);
        lblBaseAns.setText(base2);
      }


     }
    }

Answer 1

问题是，对于每个if()语句，比如if（Button32.isSelected（）），在末尾有一个;符号。这不应该在那里。这是正确的代码

class Calc implements ActionListener {
    public void actionPerformed(ActionEvent event){
        double base = 0.00;
        double options;
        double total;

        if (Button25.isSelected()){ // changed
            base = base + 999.99;
            String base2 = Double.toString(base);
            lblBaseAns.setText(base2);
        }
        else if (Button32.isSelected()){ // changed
            base = base + 1049.99;
            String base2 = Double.toString(base);
            lblBaseAns.setText(base2);
        }
        else if (Button35.isSelected()){ // changed
            base = base + 1099.99;
            String base2 = Double.toString(base);
            lblBaseAns.setText(base2);
        }
        else if (Button42.isSelected()){ // changed
            base = base + 1155.99;
            String base2 = Double.toString(base);
            lblBaseAns.setText(base2);
        }
    }
}

另一种选择是，为什么不从ActionEvent获取单击的按钮，然后使用if-else分支中的按钮

class Calc implements ActionListener {
    public void actionPerformed(ActionEvent event){
        double base = 0.00;
        double options;
        double total;

        Object clickedObject = event.getSource();
        if (clickedObject instanceof JRadioButton){
            JRadioButton clickedButton = (JRadioButton)clickedObject;

            if (clickedButton == Button25){
                base = base + 999.99;
                String base2 = Double.toString(base);
                lblBaseAns.setText(base2);
            }
            else if (clickedButton == Button32){
                base = base + 1049.99;
                String base2 = Double.toString(base);
                lblBaseAns.setText(base2);
            }
            else if (clickedButton == Button35){
                base = base + 1099.99;
                String base2 = Double.toString(base);
                lblBaseAns.setText(base2);
            }
            else if (clickedButton == Button42){
                base = base + 1155.99;
                String base2 = Double.toString(base);
                lblBaseAns.setText(base2);
            }
        }
    }
}