我正在进行测验申请。当我按下视图中的某个键时，模型会通过控制器进行更新。但是模型中的函数最初被称为1次。下次按一次键2次，下次再按3次，等等。
我完全不知道这是怎么回事。我已经尝试过调试它并没有从多个地方调用它。只是从1个地方。它几乎就像关键事件堆积并继续调用方法。
这是我的多个类的代码。
获取关键事件的测验视图：
/**
* This class will show the questions and react on the keyboard events
* @author Matthias Claes
*
*/
public class QuizView extends JPanel implements View {
private Observable $model;
private Controller $controller;
private Question $question;
private boolean $isPressed; /* To check if we already listened to a key press event */
public QuizView(Observable model, Controller controller){
setFocusable(true);
$model = model;
if (controller == null)
$controller = new QuizController(model);
else
$controller = controller;
$question = null;
$isPressed = false;
/* Add a keylistener for every team */
addKeyListener(new KeyAdapter() {
public void keyTyped(KeyEvent e) {
int teamSize; /* team size*/
teamSize = ((QuizModel) getModel()).getTeams().size();
if (Character.getNumericValue(e.getKeyChar()) <= teamSize) { /* If you pressed a number under the teamsize we listen to it, and there hasn't been pressed before */
buttonPressed(Character.getNumericValue(e.getKeyChar()));
// Else ignore the key stroke
}
}
});
}
/**
* If a button gets pressed we call this function
* @param team the team that pressed their button
*/
protected void buttonPressed(int team) {
/* Check if a button is pressed */
if(((QuizModel) getModel()).getTeamPressed() > 0)
$isPressed = true;
else
$isPressed = false;
/* If there hasn't been pressed yet and the question is not null */
if(!$isPressed && $question != null){
minimizeFrame(); /* Minimize the frame */
/* If this question has a media path we need to pause the audio/video, we also check if the user has installed vlcplayer and selected the right path */
if($question.getMediaPath() != null && QuizSoftwareModel.$vlcPath != null)
((QuizController)getController()).pause(); /* Pause the video */
/* Give a pop up message to the admin that a team has pushed their button */
((QuizController)getController()).showScoreView(team);
}
}
public void update(Observable arg0, Object arg1) {
$question = (Question) arg1;
System.out.println("CALLED");
if(((QuizModel) getModel()).getMaximize()) /* Only maximize the JFrame when needed */
maximizeFrame(); /* Maximize the frame first */
repaint();
}
/**
* Maximize the parent JFrame so the teams can see the question
*/
protected void maximizeFrame() {
JFrame topFrame = (JFrame) SwingUtilities.getWindowAncestor(this);
topFrame.setState(JFrame.MAXIMIZED_BOTH);
}
/**
* Minimize the parent JFrame so the teams can't see the question anymore
*/
protected void minimizeFrame() {
JFrame topFrame = (JFrame) SwingUtilities.getWindowAncestor(this);
topFrame.setState(JFrame.ICONIFIED);
}
一个视图显示一个弹出窗口，其中有一个按钮可以转到下一个问题，或者在答案错误时重播相同的问题。按下继续按钮会产生问题。
public class GiveScoreView extends JFrame implements View {
Observable $model;
Controller $controller;
private Question $question; /* Saves the question that is passed by the update */
/*GUI elements */
ArrayList<JLabel> $answerLabels;
ArrayList<JCheckBox> $checkBoxes;
JLabel $questionLabel;
JLabel $teamPressedLabel;
/* 2 buttons to resume/end the question */
JButton $resumeButton;
JButton $calculateButton;
public GiveScoreView(Observable model, Controller controller) {
setModel(model);
setController(controller);
$answerLabels = new ArrayList<JLabel>();
$checkBoxes = new ArrayList<JCheckBox>();
$questionLabel = new JLabel();
$teamPressedLabel = new JLabel();
$resumeButton = new JButton("Resume question"); /* TODO messagebundle */
$calculateButton = new JButton("Calculate score"); /* TODO messagebundle */
initializeFrame();
}
/**
* Initializes the frame
*/
private void initializeFrame() {
setTitle("Give a score to the teams"); /* TODO languagebundle, Change the title of the frame */
getContentPane().setLayout(new GridBagLayout());/* Set the layout to gridbaglayout */
addWindowListener(new WindowAdapter() {
@Override
public void windowClosing(WindowEvent e) {
dispose();
}
});
pack();
setVisible(false); /* Don't display it on default */
}
@Override
public void update(Observable arg0, Object arg1) {
$question = (Question) arg1;
/* Now we need to display this frame */
if(((QuizModel) getModel()).getDisplayScoreView()){
$teamPressedLabel.setText("Team " + Integer.toString(((QuizModel) getModel()).getTeamPressed()) + " is ready to answer!"); /* TODO messagebundle */
$teamPressedLabel.setFont(new Font("Serif", Font.PLAIN, 34)); /* Change the font */
displayScoreView();
setVisible(true); /* Now display the JFrame */
}
}
private void displayScoreView() {
Multipleanswer multipleanswerQuestion; /* a multiple answer question to display the multipleanswer questions */
Multiplechoice multiplechoiceQuestion; /* a multiple choice question to display the multiplechoice questions */
ArrayList<String> answers = null;
GridBagConstraints c = new GridBagConstraints();
/* Set the position of the JFrame so it's centered */
Dimension dim = Toolkit.getDefaultToolkit().getScreenSize();
// Determine the new location of the window
int w = getSize().width;
int h = getSize().height;
int x = (dim.width - w) / 2;
int y = (dim.height - h) / 2;
int i = 0;
// Move the window
setLocation(x - 150, y - 150);
/* Set size */
setSize(550, 300);
/* If the question isn't empty */
if (!($question == null)) {
c.anchor = GridBagConstraints.NORTHWEST;
$questionLabel.setText($question.getQuestion()); /* Set the text of the JLabel to the question itself */
$questionLabel.setFont(new Font("Serif", Font.PLAIN, 26)); /* Change the font */
getContentPane().add($teamPressedLabel,c); /* Add the label to the JFrame, the team that has pressed it's button */
c.weighty = 1.0;
/* Display the question under the team pressed text */
c.gridx = 0;
c.gridy = 1;
getContentPane().add($questionLabel,c); /* Add the label to the JFrame, the question itself */
/* If the type of the question is multipleanswer */
if ($question.getType() == QuestionType.MULTIPLEANSWER) {
/* Cast it to multipleanswer question */
multipleanswerQuestion = (Multipleanswer) $question;
/* Get the answers */
answers = multipleanswerQuestion.getAnswers();
} else if ($question.getType() == QuestionType.MULTIPLECHOICE) {
/* Cast it to multiplechoice question */
multiplechoiceQuestion = (Multiplechoice) $question;
/* Get the answers */
answers = multiplechoiceQuestion.getAnswers();
}
/* Speed questions don't show answers so we only display answers if it's not a speed question */
if ($question.getType() != QuestionType.SPEED) {
/* Make a JLabel and JCheckBox for each answer */
for (i = 0; i < answers.size(); i++) {
$answerLabels.add(new JLabel(answers.get(i))); /* Make a new JLabel with answer string as text */
$checkBoxes.add(new JCheckBox()); /* Make a new JCheckBox */
$answerLabels.get(i).setFont(new Font("Serif", Font.PLAIN, 16));
c.gridx = 0;
c.gridy = i + 2;
getContentPane().add($answerLabels.get(i),c); /* Add the label to the JFrame */
c.gridx = 1;
c.gridy = i + 2;
getContentPane().add($checkBoxes.get(i),c); /* Add the checkbox to the JFrame */
}
}
/* Add actionlisteners to the buttons */
$resumeButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if($question.getMediaPath() != null && QuizSoftwareModel.$vlcPath != null) /* If there is an audio/video piece */
((GiveScoreController)getController()).resumeMP(); /* Resume the mediaplayer if there is an audio/video piece */
((GiveScoreController)getController()).resumeQuestion(); /* Resume the question */
closeFrame(); /* Close the frame */
}
});
$calculateButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if($question.getMediaPath() != null && QuizSoftwareModel.$vlcPath != null) /* If there is an audio/video piece */
((GiveScoreController)getController()).closeMP(); /* Close the mediaplayer */
((GiveScoreController)getController()).nextQuestion(); /* Go on to the next question */
closeFrame(); /* Close the frame */
}
});
/* Place the buttons */
c.gridx = 0;
c.gridy = i + 2;
getContentPane().add($resumeButton);
c.gridx = 1;
c.gridy = i + 2;
getContentPane().add($calculateButton);
}
}
giveScoreView的控制器：
/**
* This class represents the controller of the GiveScoreView
* @author Matthias Claes
*
*/
public class GiveScoreController extends AbstractController {
public GiveScoreController(Observable model) {
super(model);
}
/**
* Resume the question so other teams can answer it
*/
public void resumeQuestion() {
((QuizModel) getModel()).resumeQuestion(); /* Resume the question */
}
}
测验模型：
/**
* The model of the quiz
* @author Matthias Claes
*
*/
public class QuizModel extends Observable {
private ArrayList<Question> $questions;
private ArrayList<Team> $teams;
private Question $currentQuestion;
private MediaPlayer $mp;
private int $i; /* The position in the questions, at which question we are at the moment */
private int $teamPressed; /* The team that pressed their button */
private boolean $running;
private boolean $displayScoreView;
private boolean $maximize; /* A boolean that tells the QuizView if we need to maximize this JFrame again */
/**
* Constructor for QuizModel
* @param questions a list of questions
*/
public QuizModel(ArrayList<Question> questions){
$mp = new MediaPlayer(this, null); /* null -> Give the default controller as parameter */
this.addObserver($mp);
$teams = new ArrayList<Team>();
if (questions != null) {
$questions = questions;
}
else
$questions = new ArrayList<Question>();
$currentQuestion = null;
$teamPressed = 0; /* Default value*/
$maximize = false; /* Default value */
$i = 0;
$running = false;
$displayScoreView = false;
}
/**
* Starts the quiz
*/
public void start() {
if (initialized()) {// quiz properly initialized
$running = true;
nextQuestion();
}
else {
// TODO what happens when the quiz isn't properly initialized yet
}
}
/**
* Will create a view where the admin can choose the score if the answer was right, resume if the answer was false.
* @param i the team that pushed the button
*/
public void showScoreView(int i) {
$teamPressed = i;
setDisplayScoreView(true);
/* Update the view */
System.out.println("show score view");
setChanged();
notifyObservers($currentQuestion);
}
/**
* Get the boolean displayScoreView
* @return returns true of false, depending on the displayScoreView boolean
*/
public boolean getDisplayScoreView(){
return $displayScoreView;
}
/**
* Set the $displayScoreView boolean
* @param displayScoreView the new value of $displayScoreView
*/
public void setDisplayScoreView(boolean displayScoreView){
$displayScoreView = displayScoreView;
}
/**
* Goes to the next question in the quiz
*/
public void nextQuestion(){
if($running == true && $i < $questions.size()){
$currentQuestion = $questions.get($i);
$i++;
/* This question has a mediaPath but the user doesn't have vlc installed or selected the wrong folder, so they can't use this question, so we go to the next one */
if($currentQuestion.getMediaPath() != null && QuizSoftwareModel.$vlcPath == null){
JOptionPane.showMessageDialog(null, QuizSoftwareModel.$messages.getString("videoDisplayError"));
nextQuestion(); /* go the next question */
}
/* Display the question */
else{
System.out.println("Diplay first question");
setChanged();
notifyObservers($currentQuestion);
}
} /* End of the quiz */
else{
/* Show winner TODO */
}
}
public Question getCurrentQuestion() {
return $currentQuestion;
}
public int getI() {
return $i;
}
/**
* Resume the question
*/
public void resumeQuestion() {
$teamPressed = 0; /* Reset the team that has pressed so other teams can press aswell */
$maximize = true; /* Maximize the screen again */
$displayScoreView = false;
/* TODO SAVE THE TEAM INTO AN ARRAY SO THIS TEAM CAN'T PRESS AGAIN */
System.out.println("RESUME");
this.setChanged();
this.notifyObservers($currentQuestion);
}
/**
* Return the $maximize boolean
* @return returns the $maximize boolean
*/
public boolean getMaximize() {
return $maximize;
}
}
我得到的输出是这样的：
Diplay第一个问题
CALLED
显示得分视图
CALLED
RESUME
CALLED
显示得分视图
CALLED
RESUME
CALLED
RESUME
CALLED
因此quizmodel中的resume方法被多次调用。
我不知道是否有人可以帮助我，但谢谢。 我为很长的帖子道歉，但我不知道如何向你们展示它。
答案 0 :(得分：2)
在方法displayScoreView()中，您要为ActionListener引用的按钮添加$resumeButton，最终会调用resumeQuestion()方法。
由于displayScoreView()是一个可以多次调用的实例方法（似乎它会），而$resumeButton包含相同的按钮实例GiveScoreView实例的整个生命周期可能是多个听众在该按钮上注册了同样的事情（即调用resumeQuestion()）。
请注意，如果很难找到代码实际上在做什么，你应该考虑清理它......
答案 1 :(得分：0)
您遇到的这种行为表明，每次程序做出反应时，您都会向输入添加新的侦听器。尝试移动此代码块：
/* Add actionlisteners to the buttons */
$resumeButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if($question.getMediaPath() != null && QuizSoftwareModel.$vlcPath != null) /* If there is an audio/video piece */
((GiveScoreController)getController()).resumeMP(); /* Resume the mediaplayer if there is an audio/video piece */
((GiveScoreController)getController()).resumeQuestion(); /* Resume the question */
closeFrame(); /* Close the frame */
}
});
$calculateButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if($question.getMediaPath() != null && QuizSoftwareModel.$vlcPath != null) /* If there is an audio/video piece */
((GiveScoreController)getController()).closeMP(); /* Close the mediaplayer */
((GiveScoreController)getController()).nextQuestion(); /* Go on to the next question */
closeFrame(); /* Close the frame */
}
});
在构造函数内部，在代码下面：
$resumeButton = new JButton("Resume question"); /* TODO messagebundle */
$calculateButton = new JButton("Calculate score"); /* TODO messagebundle */
这样，你只为每个按钮创建一个监听器。