RadioButton值遞增遞減使用Java

Question

這是一個在線考試系統。 如果答案正確，則標記遞增 1，第二次在同一問題上正常工作 select 錯誤答案 ii 需要減少值

  int marks;
    String cor;
        public void answerCheck()
            {
                String answerAnswer="";

                if(r1.isSelected())
                {
                    answerAnswer = r1.getText();

                }

               else if(r2.isSelected())
                {
                    answerAnswer = r2.getText();

                }

                   else if(r3.isSelected())
                {
                    answerAnswer = r3.getText();

                }

                    else if(r4.isSelected())
                {

                    answerAnswer = r4.getText();

                }

                if(answerAnswer.equals(cor))
                {
                    marks = marks + 1;
                    String Marks = String.valueOf(marks);
                    txtc.setText(Marks);
                }
                else if(!answerAnswer.equals(cor))
                {
                     marks = marks - 1;
                    String Marks = String.valueOf(marks);
                    txtc.setText(Marks);

                }
                else
                {
                    marks =0;
                }

            }

我正在從數據庫中加載所有數據正確答案我也在加載數據庫加載

public void Connection()
   {


             Class.forName("com.mysql.jdbc.Driver");
             con = DriverManager.getConnection("jdbc:mysql://localhost/onlineex","root","");
               String query = "select * from questions";
       pst = con.prepareStatement(query);

             rs = pst.executeQuery();

                  while(rs.next())
            {     
                txtqu.setText(rs.getString("id"));
                txtques.setText(rs.getString("question"));
                r1.setText(rs.getString(3));
                r2.setText(rs.getString(4));
                r3.setText(rs.getString(5));
                r4.setText(rs.getString(6));
                 cor = rs.getString(7);
            }

             } 

接下來我有一個按鈕呼叫

 try
           {

            if(rs.previous())
            {   

                txtques.setText(rs.getString("question"));
                r1.setText(rs.getString(3));
                r2.setText(rs.getString(4));
                r3.setText(rs.getString(5));
                r4.setText(rs.getString(6));

            cor=rs.getString(7);
            }
            else
                {
                    JOptionPane.showMessageDialog(this, "This is first record of student");
                }
        answerCheck();
      }

我之前有按鈕調用

if(rs.next())
        {   

            txtques.setText(rs.getString("question"));
            r1.setText(rs.getString(3));
            r2.setText(rs.getString(4));
            r3.setText(rs.getString(5));
            r4.setText(rs.getString(6));

        cor=rs.getString(7);
        }
        else
            {
                JOptionPane.showMessageDialog(this, "This is first record of student");
            }
    answerCheck();

Answer 1

首先，最后一個 else 中存在一個永遠不會執行的邏輯錯誤，因為答案是正確的或錯誤的，沒有第三個條件。

String cor;
    public void answerCheck()
        {
            String answerAnswer="";

            if(r1.isSelected())
            {
                answerAnswer = r1.getText();

            }

           else if(r2.isSelected())
            {
                answerAnswer = r2.getText();

            }

               else if(r3.isSelected())
            {
                answerAnswer = r3.getText();

            }

                else if(r4.isSelected())
            {

                answerAnswer = r4.getText();

            }

            if(answerAnswer.equals(cor))
            {
                marks = marks + 1;
                String Marks = String.valueOf(marks);
                txtc.setText(Marks);
            }
            else if(!answerAnswer.equals(cor) || ((r1.isSelected() || 
                    r2.isSelected() || r3.isSelected() || r4.isSelected()))
            {
                 marks = marks - 1;
                String Marks = String.valueOf(marks);
                txtc.setText(Marks);

            }

}