我遇到这个代码的问题，因为quizzcount变量没有输出正确的值，它使值加倍。
我通过将quizzcount潜水2来找到了解决方法并且它有效，但我真的想弄明白为什么它的价值加倍。
因此，例如，如果不将quizzcount除以2，如果用户在10个问题中得到7个正确，则messagedialog将显示用户得到14个中的14个正确。
造成这种情况的原因是什么？
谢谢你们，任何帮助都将不胜感激。
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.InvalidClassException;
import java.io.IOException;
import java.io.NotSerializableException;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.io.*;
import java.util.*;
import java.awt.* ;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;
import java.awt.Image;
import java.lang.*;
public class MathFiles extends JFrame implements ActionListener
{
private ObjectOutputStream toFile;
private String name;
private boolean open;
private static String response;
private static int menuOption = 0;
private static int numberOfMaths = 0;
private FileInputStream fis;
private ObjectInputStream fromFile;
Math aMath = null;
private int quizcount =0;
String checkbutton = "";
private static int tracker =1;
int count = 0;
int fimage =0;
JRadioButton questA, questB, questC, questD, questE;
ButtonGroup questGroup;
JPanel questPanel;
JLabel question;
JPanel questionPanel;
JTextField resultText;
JLabel resultLabl;
JPanel resultPanel;
JButton nextButton;
JPanel quizPanel;
ImageIcon image;
JLabel imageLabl;
JPanel imagePanel;
JTextArea questionText;
JScrollPane scrollPane;
Random rand;
/** @param fileName is the desired name for the binary file. */
public MathFiles()
{
setTitle( "Math Quiz Competition" );
rand = new Random();
toFile = null;
//tracker = rand.nextInt(5)+1;
tracker = 1;
name = "Quiz"+tracker+".txt";
open = false;
//openFile(); //Use only when creating file
//writeMathsToTextFile(name);
setLayout( new FlowLayout() );
inputFile();
beginquiz();
showquestions();
setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
} // end MathFiles constructor
/** Writes all Maths from a text file and writes them to a binary file.
@param fileName the text file */
public void writeMathsToTextFile(String fileName)
{
Scanner inputFile = null;
Math nextMath = null;
String question_num;
String question;
String answera;
String answerb;
String answerc;
String answerd;
String answer_cor;
String file_name;
String SENTINEL ="DONE";
try
{
inputFile = new Scanner(new File(fileName));
}
catch(FileNotFoundException e)
{
System.out.println("Text file " + fileName + " not found.");
System.exit(0);
}
Scanner keyboard = new Scanner(System.in);
System.out.print("Question number: ");
question_num = keyboard.nextLine();
while (!question_num.equalsIgnoreCase(SENTINEL))
{
System.out.print("Question: ");
question = keyboard.nextLine();
System.out.print("Answer A: ");
answera = keyboard.nextLine();
System.out.print("Answer B: ");
answerb = keyboard.nextLine();
System.out.print("Answer C: ");
answerc = keyboard.nextLine();
System.out.print("Answer D: ");
answerd = keyboard.nextLine();
fimage = rand.nextInt(30)+1;
file_name = "image"+fimage+".gif";
System.out.print(file_name);
System.out.print("Correct Answer: ");
answer_cor = keyboard.nextLine();
nextMath = new Math(question_num, question, answera, answerb,
answerc, answerd, answer_cor, file_name);
writeAnObject(nextMath);
numberOfMaths++;
System.out.print("\nQuestion number: ");
question_num = keyboard.nextLine();
} // end while
System.out.println("successfully created = " + name);
} // end readMathsFromTextFile
/** Opens the binary file for output. */
public void openFile()
{
try
{
FileOutputStream fos = new FileOutputStream(name);
toFile = new ObjectOutputStream(fos);
open = true;
}
catch (FileNotFoundException e)
{
System.out.println("Cannot find, create, or open the file " + name);
System.out.println(e.getMessage());
open = false;
}
catch (IOException e)
{
System.out.println("Error opening the file " + name);
System.out.println(e.getMessage());
open = false;
}
//System.out.println("successfully opened = " + name);
} // end openFile
/** Writes the given object to the binary file. */
public void writeAnObject(Serializable anObject)
{
try
{
if (open)
toFile.writeObject(anObject);
}
catch (InvalidClassException e)
{
System.out.println("Serialization problem in writeAnObject.");
System.out.println(e.getMessage());
System.exit(0);
}
catch (IOException e)
{
System.out.println("Error writing the file " + name);
System.out.println(e.getMessage());
System.exit(0);
}
} // end writeAnObject
public void result()
{
System.out.println("Your score is");
}
public void inputFile()
{
try
{
fromFile = new ObjectInputStream(new FileInputStream(name));
}
catch(StreamCorruptedException e)
{
System.out.println("Error in input stream: " + name);
System.out.println(e.getMessage());
System.exit(0);
}
catch(IOException e)
{
System.out.println("Error reading input stream: " + name);
System.out.println(e.getMessage());
System.exit(0);
}
} // end displayFile
/** Closes the binary file. */
public void closeFile()
{
System.out.println("closed name = " + name);
try
{
toFile.close();
open = false;
}
catch (IOException e)
{
System.out.println("Error closing the file " + name);
System.out.println(e.getMessage());
System.exit(0);
}
} // end closeFile
/** @return the fileís name as a string */
public String getName()
{
return name;
} // end getName
/** @return true if the file is open */
public boolean isOpen()
{
return open;
} // end isOpen
public void beginquiz()
{
try
{
aMath = (Math)fromFile.readObject();
}
catch (ClassNotFoundException e)
{
System.out.println("The class Math is not found.");
System.out.println(e.getMessage());
System.exit(0);
}
catch(StreamCorruptedException e)
{
System.out.println("Error in input stream: " + name);
System.out.println(e.getMessage());
System.exit(0);
}
catch(IOException e)
{
System.out.println("Error reading input stream: " + name);
System.out.println(e.getMessage());
System.exit(0);
}
}
void showquestions()
{
//question group
/*question = new JLabel();
question.setText(aMath.getquestion());
question.setFont(new Font("Arial", Font.BOLD, 20));
question.setForeground(Color.BLUE);
questionPanel = new JPanel();
questionPanel.add( question );*/
questionText = new JTextArea(5,20);
questionText.setWrapStyleWord(true);
questionText.setLineWrap(true);
questionText.setText(aMath.getquestion());
questionText.setFont(new Font("Arial", Font.BOLD, 20));
questionText.setForeground(Color.BLUE);
questionPanel = new JPanel();
questionPanel.setLayout(new BoxLayout(questionPanel, BoxLayout.PAGE_AXIS));
questionPanel.add( questionText );
// quest group
questA = new JRadioButton(aMath.getanswera(), false );
questB = new JRadioButton(aMath.getanswerb(), false );
questC = new JRadioButton(aMath.getanswerc(), false );
questD = new JRadioButton(aMath.getanswerd(), false );
questGroup = new ButtonGroup();
questGroup.add( questA );
questGroup.add( questB );
questGroup.add( questC );
questGroup.add( questD );
questPanel = new JPanel();
questPanel.setLayout( new BoxLayout( questPanel, BoxLayout.Y_AXIS ) );
questPanel.add( new JLabel("Choose the Correct Answer") );
questPanel.add( questA );
questPanel.add( questB );
questPanel.add( questC );
questPanel.add( questD );
// result panel
//resultText = new JTextField(20);
//resultText.setEditable( false );
//resultLabl = new JLabel("Result");
//resultPanel = new JPanel();
//resultPanel.add( resultLabl );
//resultPanel.add( resultText );
//button
nextButton = new JButton("Next");
quizPanel = new JPanel();
quizPanel.add(nextButton);
//Image image1 = new ImageIcon("image/image1.gif").getImage();
image = new ImageIcon("image1.gif");
imageLabl=new JLabel(image);
imagePanel = new JPanel();
imagePanel.add(imageLabl);
// frame: use default layout manager
add( imagePanel);
add( questionPanel);
add( questPanel);
//add( resultPanel);
questA.setActionCommand(aMath.getanswera());
questB.setActionCommand(aMath.getanswerb());
questC.setActionCommand(aMath.getanswerc());
questD.setActionCommand(aMath.getanswerd());
questA.addActionListener(this);
questB.addActionListener(this);
questC.addActionListener(this);
questD.addActionListener(this);
nextButton.setActionCommand( "next" ); // set the command
// register the buttonDemo frame
// as the listener for both Buttons.
nextButton.addActionListener( this );
add(quizPanel);
}
public void actionPerformed( ActionEvent evt)
{
//evt.getActionCommand() = aMath.getanswer_cor();
if (questA.isSelected()&&
aMath.getanswera().equalsIgnoreCase(aMath.getanswer_cor().trim()))
quizcount++;
if (questB.isSelected()&&
aMath.getanswerb().equalsIgnoreCase(aMath.getanswer_cor().trim()))
quizcount++;
if (questC.isSelected()&&
aMath.getanswerc().equalsIgnoreCase(aMath.getanswer_cor().trim()))
quizcount++;
if (questD.isSelected()&&
aMath.getanswerd().equalsIgnoreCase(aMath.getanswer_cor().trim()))
quizcount++;
if(questA.isSelected() || questB.isSelected() || questC.isSelected() || questD.isSelected())
if ( evt.getActionCommand().equals( "next" ))
{
try
{
aMath = (Math)fromFile.readObject();
questionText.setText(aMath.getquestion());
questA.setText(aMath.getanswera());
questB.setText(aMath.getanswerb());
questC.setText(aMath.getanswerc());
questD.setText(aMath.getanswerd());
imageLabl.setIcon(new ImageIcon(aMath.getfile()));
questGroup.clearSelection();
repaint();
}
catch (ClassNotFoundException e)
{
System.out.println("The class Math is not found.");
System.out.println(e.getMessage());
System.exit(0);
}
catch(StreamCorruptedException e)
{
System.out.println("Error in input stream: " + name);
System.out.println(e.getMessage());
System.exit(0);
}
catch(IOException e)
{
if (count<=0)
count = 0;
else
count--;
JOptionPane.showMessageDialog(null,"Your score is "+quizcount/2 +" out of 10");
try{
Thread.sleep(2000);
System.exit(0);
}catch (InterruptedException em) { }
}
}
}
public static void main ( String[] args )
{
MathFiles mat = new MathFiles();
mat.setSize( 450, 550 );
mat.setLocationRelativeTo(null);
mat.setResizable( false );
mat.setVisible( true );
}
} // end MathFiles
class Math implements java.io.Serializable
{
private String question_num;
private String question;
private String answera;
private String answerb;
private String answerc;
private String answerd;
private String answer_cor;
private String file_name;
public Math(String quesno, String quest, String ansa, String ansb, String ansc,
String ansd, String ans_cor, String file)
{
question_num = quesno;
question = quest;
answera = ansa;
answerb = ansb;
answerc = ansc;
answerd = ansd;
answer_cor = ans_cor;
file_name = file;
}
public void setquestion(String lName)
{
question = lName;
} // end setquestion
public void setquestion_num(String fName)
{
question_num = fName;
} // end setquestion_num
public void setanswera(String add)
{
answera = add;
} // end setanswera
public void setanswerb(String cty)
{
answerb = cty;
} // end setanswerb
public void setanswerc(String st)
{
answerc = st;
} // end setanswerc
public void setanswerd(String z)
{
answerd = z;
} // end setanswerd
public void setanswer_cor(String phn)
{
answer_cor = phn;
} // end setanswer_corr
public String getquestion_num()
{
return question_num;
} // end getquestion_num
/** @return the question */
public String getquestion()
{
return question;
} // end getquestion
/** @return the answera*/
public String getanswera()
{
return answera;
} // end getanswera
/** @return the answerb */
public String getanswerb()
{
return answerb;
} // end getanswerb
public String getanswerc()
{
return answerc;
} // end getanswerc
public String getanswerd()
{
return answerd;
} // end getanswerd
public String getanswer_cor()
{
return answer_cor;
} // end getanswer_corr
public String getfile()
{
return file_name;
} // end getanswer_corr
/** @return the Math information */
public String toString()
{
String myMath = getquestion_num() + " " + getquestion() + "\n";
myMath += getanswera() + "\n";
myMath += getanswerb() + " " + getanswerc() + " " + getanswerd() + "\n";
myMath += getanswer_cor() + "\n";
myMath += getfile() + "\n";
return myMath;
} // end toString
} // end Math
答案 0 :(得分：0)
看起来您的问题是您已在单选按钮上注册了ActionListeners。这意味着当您选择答案并单击“下一步”按钮时会触发事件。考虑到这一点，显而易见的是，为什么你的分数会翻倍。
据我所知，单选按钮不需要ActionListeners。您应该只在用户表明已完成选择时检查答案。分数正好加倍，这也表明除了天真地选择一个单选按钮并点击“下一步”之外，你基本上没有测试过程序。在注释掉将侦听器添加到单选按钮的行之前，请尝试更改答案。打开程序，选择正确答案，然后选择错误答案，然后再次选择正确答案并单击“下一步”。看看会发生什么。
使用调试器也可以轻松找到此类错误。只需在actionPerformed中插入一个断点，很明显它会被多个动作调用。