When JPanel changes, elements of the old JPanel are left behind

Question

I'm using a JTabbedPane, and on each tab there's a panel, which changes when the user does things like click buttons. The problem I'm getting is that elements from the previous panel get left behind. Usually you can't see them until you run the mouse over them, but sometimes you can't see elements of the new panel until you run your mouse over where they should be. So quite often at first only a little is visible, then:

when you run your mouse over more stuff it becomes visible

Then for some reason when you hit 'multiple choice', which is supposed to create the four new buttons, everything becomes perfectly visible.

I've got repaint(); as pretty much every other line, and before I change anything on the GUI I do removeAll(); first, but it all keeps coming back! Any suggestions? The code for this panel is below, if it might help...

package com.GC01.gui;

import java.awt.Color;

public class PracticeQuizPanel extends JPanel implements MouseListener {
    /**
     * This panel will allow the user to practice quiz questions.
     */
private static final long serialVersionUID = 1L;

private User user = new User("misha");

boolean isMultipleChoice=false;
boolean usedClue=false;
boolean isStarted=false;

Calendar calendar = Calendar.getInstance();
AnswerAnalysis aA = new AnswerAnalysis();   
private Quiz qz = new Quiz( Quiz.getQuestionsFromDisk(), 4, TabbedQuiz.getUser().getNumLogins() );

private JTextArea questionArea;
private JTextArea clueArea;
private JTextArea answerArea;

private JButton clueButton;
private JButton multiButton;
private JButton answerButton;
private JButton startButton; 

private int index=0;
private Calendar startCalendar, endCalendar;

private JPanel backPanel;

public PracticeQuizPanel(){
    add(new StartButtonPanel());
}

PracticeQuizPanel(int index) {
    createVisualElements(index);
}

public void offerAnswer(){
    endCalendar = Calendar.getInstance();
    aA.setTimeSpent((int) (endCalendar.getTimeInMillis()-startCalendar.getTimeInMillis()));
    aA.setRight(answerArea.getText());
    JOptionPane.showMessageDialog(null, aA.toString());
    answerArea.setEditable(false);
    qz.setAnswersAnalysis(index, aA);
    index++;
    removeAll(); 
    if( index<qz.getLength() ) createVisualElements(index);
    else {
        removeAll();
        JOptionPane.showMessageDialog(null, qz.toFriendlyString());
        addQuizResultsToUserProgress();
        JOptionPane.showMessageDialog(null, qz.toFriendlyString());
        UserProgress uP = new UserProgress(user);
        System.out.println(uP.toString());
    }
    repaint();
    startCalendar = Calendar.getInstance();
    //JOptionPane.showMessageDialog(null, isStarted);
}

public void addQuizResultsToUserProgress(){
    UserProgress userProgress = new UserProgress(user);
    ArrayList<AnswerAnalysis> asA = userProgress.getAnswersAnalysis();
    for (int i=0; i<qz.getLength(); i++){
        asA.add( qz.getAnswersAnalysis()[i]);
    }
    userProgress.setAnswersAnalysis(asA);
    userProgress.saveProgress();
}



/**
 * This method creates/recreates all the text boxes, buttons etc. without resetting the quiz and
 * the objects in memory.
 */
private void createVisualElements(int index){
    if (TabbedQuiz.getUser().getNumLogins()<0) 
        JOptionPane.showMessageDialog(null, "There was an error. You may have done this quiz before.");
    removeAll();
    repaint();
    startCalendar = Calendar.getInstance();
    this.index=index;
    setBackground(new Color(112, 128, 144)); 
    setBounds(0,0,728,380);
    setLayout(null);

    questionArea = new JTextArea();
    questionArea.setFont(TabbedQuiz.getDefaultFont().deriveFont(20));//new Font("Courier New", 0, 20));
    questionArea.setEditable(false);
    questionArea.setLineWrap(true);
    questionArea.setWrapStyleWord(true);
    questionArea.setBounds(295, 11, 423, 74);
    add(questionArea);
    //int index=0;
    Question q = qz.getQuestions().get(index);
    aA = new AnswerAnalysis(q.getQuestionID());
    questionArea.setText(q.getQuestionText() );

    clueArea = new JTextArea();
    clueArea.setFont(TabbedQuiz.getDefaultFont().deriveFont(20));
    clueArea.setEditable(false);
    clueArea.setLineWrap(true);
    clueArea.setWrapStyleWord(true);
    clueArea.setBounds(295, 104, 423, 55);
    add(clueArea);

    JLabel lblQuestion = new JLabel("QUESTION:");
    lblQuestion.setFont(TabbedQuiz.getDefaultFont().deriveFont(40));
    lblQuestion.setBounds(43, 11, 216, 61);
    add(lblQuestion);

    answerArea = new JTextArea();//index+"");
    answerArea.setFont(TabbedQuiz.getDefaultFont().deriveFont(20));
    answerArea.setLineWrap(true);
    answerArea.setWrapStyleWord(true);
    answerArea.setBounds(295, 301, 423, 50);
    answerArea.addKeyListener(new KeyAdapter() {
        @Override
        public void keyPressed(KeyEvent e) {
            if(e.getKeyCode() == KeyEvent.VK_ENTER) offerAnswer();
        }
    });

    add(answerArea);
    answerArea.setFocusable(true);
    answerArea.requestFocusInWindow();

    clueButton = new JButton("CLUE?");
    clueButton.setFont(TabbedQuiz.getDefaultFont().deriveFont(40));
    clueButton.addMouseListener(this);
    clueButton.setBounds(15, 104, 244, 55);
    add(clueButton);

    multiButton = new JButton("MULTIPLE CHOICE?");
    multiButton.setFont(TabbedQuiz.getDefaultFont().deriveFont(20));
    multiButton.addMouseListener(this);
    multiButton.setBounds(15, 195, 244, 55);
    add(multiButton);

    answerButton = new JButton("ANSWER!");
    answerButton.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent arg0) {
        }
    });
    answerButton.setFont(TabbedQuiz.getDefaultFont().deriveFont(40));
    answerButton.setBounds(15, 301, 244, 55);
    answerButton.addMouseListener(this);
    add(answerButton);

    backPanel = new JPanel();
    backPanel.setBounds(0, 0, 728, 380);
    //add(backPanel);

    this.setVisible(true);
    repaint();
}

@Override
public void mouseClicked(MouseEvent e) {
    if      ( e.getSource().equals(startButton)  ) {
        remove(startButton); repaint(); isStarted=true;
        startCalendar = Calendar.getInstance();
    }
    else if ( e.getSource().equals(answerButton) ) offerAnswer();
    else if ( e.getSource().equals(clueButton )  ) {
        clueArea.setText(clueArea.getText() + qz.getQuestions().get(index).getClueText() + "\n");
        aA.setUsedClue(true);
        //JOptionPane.showMessageDialog(null, "hi");
        }
    else if ( e.getSource().equals(multiButton)  ) {            
        String[] answerOptions = qz.getQuestions().get(index).getAnswerOptions(3);
        JButton[] optionsButtons = new JButton[4];
        for(int j=0;j<4;j++){
            optionsButtons[j]=new JButton(answerOptions[j]);
            if(optionsButtons[j].getText().length()>13) 
                optionsButtons[j].setFont(TabbedQuiz.getDefaultFont().deriveFont(10));
            else optionsButtons[j].setFont(TabbedQuiz.getDefaultFont().deriveFont(15));
            if(j<2) optionsButtons[j].setBounds(295+211*j       , 170, 211, 55);
            else    optionsButtons[j].setBounds(295+211*(j-2)   , 226, 211, 55);
            optionsButtons[j].addMouseListener(this);
            optionsButtons[j].setName("optionsButton"+"["+j+"]");
            add(optionsButtons[j]);
            repaint();
        }
        aA.setMultipleChoice(true);
    }
    else if ( ( (JButton) e.getSource() ).getName().startsWith("optionsButton") ) {
        String answerOffered = ( (JButton) e.getSource() ).getText();
        answerArea.setText(answerOffered);
        offerAnswer();
    }
}

@Override
public void mouseEntered(MouseEvent e) {
    if(e.getSource()!=startButton && e.getSource().getClass().equals( answerButton.getClass()) ){
        ( (JButton) e.getSource() ).setBackground(Color.green);
    }if(index>0 && e.getSource()==startButton) remove(startButton);
}

@Override
public void mouseExited(MouseEvent e) {
    if(e.getSource()!=startButton && e.getSource().getClass().equals( answerButton.getClass()) ){
        ( (JButton) e.getSource() ).setBackground(UIManager.getColor("control"));
    }
}

@Override
public void mousePressed(MouseEvent e) {
}

@Override
public void mouseReleased(MouseEvent e) {
}
}

score 3 · Answer 1 · edited Jun 20 '20 at 09:12

3

and on each tab there's a panel, which changes when the user does things like click buttons.

and before I change anything on the GUI I do removeAll();

Whenever I see comments like that it sounds to me like you should be using a Card Layout so you don't have to worry about all these problems.

edited Jun 20 '20 at 09:12

Community

1
1

answered Nov 11 '11 at 02:15

camickr

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Hovercraft Full Of Eels · Answer 2 · 2011-11-12T04:04:44.577

2

You need to call revalidate after removing or adding components to a container if using layout managers. Then after that you call repaint.

You've posted a lot of code, and most of it is completely unrelated to the problem at hand, but on the other hand, the code posted is incomplete, won't compile, and thus is not code that we can test. Please next time, try not posting a lot of code that's not relevant to the problem. Try to isolate the problem by continually cutting out code, and then if still stuck, post a minimal compiable program that we can study, test, run, and modify ourselves, an sscce.

I've gone through some of your GUI code (for gosh's sake, not all!), and there's some big time badness there where you're stepping on Swing painting such as this code from ProgressPanel.java:

   public void paintComponent(Graphics g) {
      super.paintComponent(g);
      Graphics2D g2d = (Graphics2D) g;
      createAndShowGUI(g2d);
      // drawDifficultyChart(g2d, fontComboBox.getSelectedIndex());
   }

   private void createAndShowGUI(Graphics2D g2d) {
      JButton showChartButton = new JButton("Show new chart!");
      user = TabbedQuiz.getUser();
      showChartButton.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent e) {
            try {
               if (categoryComboBox.getSelectedIndex() == 0
                     && difficultyComboBox.getSelectedIndex() != 0) {
                  drawDifficultyChart((Graphics2D) getGraphics(),
                        difficultyComboBox.getSelectedIndex());
               } else if (difficultyComboBox.getSelectedIndex() == 0
                     && categoryComboBox.getSelectedIndex() != 0) {
                  drawCategoryChart((Graphics2D) getGraphics(),
                        (String) categoryComboBox.getSelectedItem());
               } else
                  drawGeneralChart((Graphics2D) getGraphics(),
                        (String) categoryComboBox.getSelectedItem(),
                        difficultyComboBox.getSelectedIndex());
            } catch (NullPointerException e1) {
               JOptionPane.showMessageDialog(null, "Sign in first.");
            }
         }
      });
      showChartButton.setBounds(10, 90, 96, 26);
      showChartButton.setFont(font);
      add(showChartButton);
   }

The problem is that you're creating and adding components to a container from within a paint/paintComponent method, something you should never be doing and something that is bound to mess up your program's graphics.

edited Nov 12 '11 at 04:04

answered Nov 11 '11 at 01:35

Hovercraft Full Of Eels

283,665
25
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I know, sorry, I've just created quite a big and sprawling project. I'll give `revalidate()` a try now. Thanks! – user1002973 Nov 11 '11 at 01:55
@user1002973: Am trying to get through your massive code post, but there are too many dangling references to be able to make sense of the logic. One unrelated problem I see though is why are you adding MouseListeners to JButtons? Makes no sense and can cause problems later. Why not use Actionlisteners instead? – Hovercraft Full Of Eels Nov 11 '11 at 02:09
I used MouseListeners because I wanted the buttons to change colour when the mouse hovers over them. Then having separate ActionListeners for the actual clicking seemed unnecessary. `revalidate()` didn't seem to do the trick, I might be using it wrongly... If I still can't solve it I'll try to reproduce the problem in a single-class project. – user1002973 Nov 11 '11 at 02:24
Not a good reason to use MouseListener. By doing this, what will happen if you try to disable the buttons? In other words it will make your buttons lose needed behaviors. Better to use a ChangeListener to listen to the button's model and then respond if `isRollover()` is true. – Hovercraft Full Of Eels Nov 11 '11 at 02:27
I've put `revalidate` everywhere, but it doesn't seem to be having the desired effect. I can't reproduce the problem in a JPanel, so I haven't worked out how to reduce the code down to a manageable size to read on this site. I have, though, put the program into a [runnable .jar file](http://dl.dropbox.com/u/20035390/rubyTeacherRunnable.jar). I would have thought it will only work on Windows, and will create a directory C://Dummy/, but it's harmless! The only tabs that really do anything are 'Welcome', 'Practice', 'View Performance' and 'Settings'. Does this seem like it's JTabbedPane's fault? – user1002973 Nov 11 '11 at 20:39
@user1002973: If you're going to upload a Jar file, why not upload one with source code included? Just looking at your running program isn't going to tell me much. And regarding the bug, it's not likely in JTabbedPane -- it's likely in *your* code. – Hovercraft Full Of Eels Nov 11 '11 at 20:41
@user1002973: no data file. Program fails. – Hovercraft Full Of Eels Nov 11 '11 at 22:53
Sorry again! You can use [this one](http://dl.dropbox.com/u/20035390/QuizQuestions.csv), if you put it in C://Dummy/ But you should be able to see the issue just by signing up/signing in. – user1002973 Nov 12 '11 at 01:02
I cannot reproduce your problem. – Hovercraft Full Of Eels Nov 12 '11 at 01:13
Ah, well that might be a good thing! Have you tried signing up? And when you do, does it look like [this -bad](http://i.imgur.com/7qiFg.png)- or [this -good](http://i.imgur.com/TETNd.png)? Thanks so much for the effort! – user1002973 Nov 12 '11 at 02:22
@user1002973: the second one. – Hovercraft Full Of Eels Nov 12 '11 at 03:04
Have changed code so that no JComponents are within the paint method any more. But I don't think that was the problem - I'm still getting it. I should have checked actually though - I didn't get the problem when I signed up for some reason, only when I sign in. Is that the same for you? – user1002973 Nov 12 '11 at 17:30
@user1002973: I am unable to reproduce the problem period. I'm using Windows 7, and had to make changes to your code to make it compliant with Java 1.6 (mainly make JComboBoxes non-generic). – Hovercraft Full Of Eels Nov 12 '11 at 17:57

score 0 · Accepted Answer · answered Nov 14 '11 at 17:41

0

To anyone else with this issue: I eventually solved the problem. setVisible(false); setVisible(true);. Put it EVERYWHERE.

answered Nov 14 '11 at 17:41

user1002973

2,088
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When JPanel changes, elements of the old JPanel are left behind

3 Answers3