我正在准备一个java测试页面，问题来自数据库但是当用户选择一个单选按钮并单击完成按钮时，无法看到他的分数。
所以程序应该比较来自数据库的单选按钮的文本和右选项字段。（最后一个问题是工作正常，因为我自己写的。它不是来自数据库。）
我认为我在单选按钮项侦听器类上有问题，但我无法找到解决方案。
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
import javax.swing.JOptionPane;
public class ExamSystem extends JFrame {
public JLabel q1,q2;
public JButton ok;
public JRadioButton a1,a2,a3,a4,b1,b2,b3,b4;
public JPanel pnl1,pnl2,pnlchoices1,pnlchoices2;
public ButtonGroup grp1,grp2,grp3,grp4,grp5;
public int score=0;
public Connection con;
public Statement st;
public ResultSet rs;
public ExamSystem () {
super("Exam");
Container container = getContentPane();
container.setLayout(new GridLayout(11,1));
pnl1 = new JPanel();
pnl1.setLayout(new GridLayout(1,1));
q1 = new JLabel();
pnl1.add(q1);
pnlchoices1 = new JPanel();
pnlchoices1.setLayout(new GridLayout(2,2));
a1 = new JRadioButton();
a2 = new JRadioButton();
a3 = new JRadioButton();
a4 = new JRadioButton();
pnlchoices1.add(a1);
pnlchoices1.add(a2);
pnlchoices1.add(a3);
pnlchoices1.add(a4);
container.add(pnl1);
container.add(pnlchoices1);
grp1 = new ButtonGroup();
grp1.add(a1);
grp1.add(a2);
grp1.add(a3);
grp1.add(a4);
try {
Class.forName("com.mysql.jdbc.Driver").newInstance();
System.out.print("sürücü yüklendi");
con = DriverManager.getConnection("jdbc:mysql://localhost:3306/etest", "root", "1234");
st = con.createStatement();
String sql = "Select * from questions";
rs = st.executeQuery(sql);
//int id_col = rs.getInt("sid");
//String id = Integer.toString(id_col);
while ( rs.next()) {
String soru = rs.getString("question");
String birinci = rs.getString("first");
String ikinci = rs.getString("second");
String ucuncu = rs.getString("third");
String dorduncu = rs.getString("forth");
String dogru = rs.getString("right");
q1.setText(soru);
a1.setText(birinci);
a2.setText(ikinci);
a3.setText(ucuncu);
a4.setText(dorduncu);
pnl1 = new JPanel();
pnl1.setLayout(new GridLayout(1,1));
q1 = new JLabel();
pnl1.add(q1);
pnlchoices1 = new JPanel();
pnlchoices1.setLayout(new GridLayout(2,2));
a1 = new JRadioButton();
a2 = new JRadioButton();
a3 = new JRadioButton();
a4 = new JRadioButton();
pnlchoices1.add(a1);
pnlchoices1.add(a2);
pnlchoices1.add(a3);
pnlchoices1.add(a4);
container.add(pnl1);
container.add(pnlchoices1);
grp1 = new ButtonGroup();
grp1.add(a1);
grp1.add(a2);
grp1.add(a3);
grp1.add(a4);
}
}
catch (Exception s)
{
System.out.print(s.getMessage());
}
pnl2 = new JPanel();
pnl2.setLayout(new GridLayout(1,1));
q2 = new JLabel(" Which one is biggest?");
pnl2.add(q2);
pnlchoices2 = new JPanel();
pnlchoices2.setLayout(new GridLayout(2,2));
b1 = new JRadioButton(" 1");
b2 = new JRadioButton(" 2");
b3 = new JRadioButton(" 3");
b4 = new JRadioButton(" 4");
pnlchoices2.add(b1);
pnlchoices2.add(b2);
pnlchoices2.add(b3);
pnlchoices2.add(b4);
container.add(pnl2);
container.add(pnlchoices2);
ok = new JButton("Finish");
ok.setBackground(Color.RED);
container.add(ok);
setSize(500,500);
setVisible(true);
RadioButtonHandler handler = new RadioButtonHandler();
a1.addItemListener(handler);
a2.addItemListener(handler);
a3.addItemListener(handler);
a4.addItemListener(handler);
b1.addItemListener(handler);
b2.addItemListener(handler);
b3.addItemListener(handler);
b4.addItemListener(handler);
grp2 = new ButtonGroup();
grp2.add(b1);
grp2.add(b2);
grp2.add(b3);
grp2.add(b4);
ButtonHandler btnHandler = new ButtonHandler();
ok.addActionListener(btnHandler);
}
public static void main(String[]args) {
ExamSystem application = new ExamSystem();
application.setDefaultCloseOperation(EXIT_ON_CLOSE);
}
public class RadioButtonHandler implements ItemListener {
public void itemStateChanged(ItemEvent event) {
if (event.getSource()==b4)
score++;
}
}
public class ButtonHandler implements ActionListener {
public void actionPerformed(ActionEvent event) {
if (event.getSource()==ok) {
JOptionPane.showMessageDialog(null,"Score: " +score,"",JOptionPane.INFORMATION_MESSAGE);
//dispose();
}
}
}
}
答案 0 :(得分：0)
您的代码存在许多问题，但最重要的问题是，即考试系统不计算总分的问题，您只需在最后一个单选按钮更改时增加分数州。您可以为其他问题选择正确或不正确的答案，但由于您的按钮处理程序仅识别单选按钮b4，因此这是唯一会影响分数的单选按钮。
（顺便提一下，当4单选按钮取消选择时，您也会增加分数，这样您可以反复点击{{1}，让分数尽可能高。例如，和4单选按钮。）
为了解决这个问题，我建议做出一些改变。
首先，我建议您不要随时跟踪得分。相反，当您单击“完成”按钮时，请运行“正确”列表。按钮并查看其中有多少个被选中（使用isSelected()方法）。添加一个名为2的字段，并将其声明为correctButtons类型，即
List<JRadioButton>我们会在private List<JRadioButton> correctButtons;
循环之前填充此列表，但在我们添加到列表之前，我们需要添加一个列表。在循环上方添加以下行：
while您还需要添加行
correctButtons = new ArrayList<JRadioButton>();
位于文件顶部。
您的代码生成一组空白单选按钮也存在问题。这是因为您在import java.util.List;
import java.util.ArrayList;
循环之前创建了一组单选按钮，每次循环创建一次。在此循环中，您可以设置最后一组单选按钮的标签并创建一个新集。当然，最后一组按钮永远不会有任何标签设置。最好只在循环内部根据需要创建单选按钮组。从while循环外部删除所有这些代码：
while在 pnl1 = new JPanel();
pnl1.setLayout(new GridLayout(1,1));
q1 = new JLabel();
// ... rest of code omitted, until
grp1.add(a3);
grp1.add(a4);
循环内，在创建标签和单选按钮后，将调用移至while，然后再向下移动。
在循环结束时，我们需要确定哪个答案是正确的，并将相应的按钮添加到正确的按钮列表中。
q1.setText()循环应如下所示：
while由于单选按钮 while ( rs.next()) {
String soru = rs.getString("question");
String birinci = rs.getString("first");
String ikinci = rs.getString("second");
String ucuncu = rs.getString("third");
String dorduncu = rs.getString("forth");
String dogru = rs.getString("right");
// Calls to q1.setText, a1.setText, etc. moved from here.
pnl1 = new JPanel();
pnl1.setLayout(new GridLayout(1,1));
q1 = new JLabel();
pnl1.add(q1);
pnlchoices1 = new JPanel();
pnlchoices1.setLayout(new GridLayout(2,2));
a1 = new JRadioButton();
a2 = new JRadioButton();
a3 = new JRadioButton();
a4 = new JRadioButton();
pnlchoices1.add(a1);
pnlchoices1.add(a2);
pnlchoices1.add(a3);
pnlchoices1.add(a4);
container.add(pnl1);
container.add(pnlchoices1);
grp1 = new ButtonGroup();
grp1.add(a1);
grp1.add(a2);
grp1.add(a3);
grp1.add(a4);
// Calls to q1.setText etc moved here.
q1.setText(soru);
a1.setText(birinci);
a2.setText(ikinci);
a3.setText(ucuncu);
a4.setText(dorduncu);
// Figure out which button is for the correct answer
// and add it to our list of correct buttons.
if (dogru.equals(birinci)) {
correctButtons.add(a1);
} else if (dogru.equals(ikinci)) {
correctButtons.add(a2);
} else if (dogru.equals(ucuncu)) {
correctButtons.add(a3);
} else if (dogru.equals(dorduncu)) {
correctButtons.add(a4);
} else {
// If we get here, the correct answer is not one of the
// options. I don't know how you want to handle this.
}
}
用于另一个正确答案，您可能还想将其添加到b4。
接下来，删除班级correctButtons以及使用它的所有RadioButtonHandler调用。我们不再需要它了。
最后，修改addItemListener班级ButtonHandler，使用以下代码计算得分。在致电actionPerformed method：
JOptionPane.showMessageDialog我对您的代码进行了这些更改，并且它按照我的预期运行。