java parsing data from component

Question

I am creating a game, and I am doing a character selection screen which has a JTextField for entering the user name, the screen also has a JButton "Create Character", which, when pressed will parse the JTextField and if any problems(space in name, begin with space, etc..) it will put some text to a JLabel next to the JTextField.

I hook up the JButton to an actionPerformed method, which calls a function that parses the data. My problem is that every time I press the button, a new label is being placed on top of the original JLabel.

I create the JLabel like this:

public static JLabel label;
label = new JLabel();
// some properties

And I call the parsing method like so:

parseCharacterSelection(nameInput, label);

where nameInput is the JTextField. My question is, why is there a new Label being created every time I press the JButton

public void parseCharacterCreation(JTextField input, JLabel label) {

    // Variable that hold whether or not
    // the User Name is acceptable

    player_name = input.getText();

    // Make some initial checks on the
    // input string
    //----------------------------------
    if( player_name.isEmpty() ) {
        label.setText("You need to pick a username");
    } else if( player_name.startsWith(" ") ) {
        label.setText("Name Cannot start with a space");
    } else {
        pass = true;
    }

    // Attempt to write to file
    // Catch some errors
    //----------------------------------
    if(pass == true) {
        try {
            if( player_name.contains(" ") ) {
                player_name = player_name.replaceAll("\\s", "_");
                player_file = new File("src/Resources/characters/" + player_name + ".properties");
            }

            if(!player_file.exists()) {
                player_file.createNewFile();
            }

            FileWriter      fw = new FileWriter(player_file.getAbsoluteFile());
            BufferedWriter  bw = new BufferedWriter(fw);

            bw.write(player_name);
            bw.close();

        } catch( IOException e ) {
            e.printStackTrace();
        } finally {
            System.out.println("DONE");
        }
    }
}

// ScreenCharacter Class

public class ScreenCharacter extends JPanel {

public static JButton       create;
public static JTextField    nameInput;
public static JLabel        errorLabel;

public ScreenCharacter() {

    this.setLayout(null);
    this.add(createUserName());
    this.add(createMainArea());
}

private static JPanel createUserName() {

    MatteBorder matteBorder = new MatteBorder(1, 0, 1, 0, Color.decode("#222222"));
    EmptyBorder emptyBorder = new EmptyBorder(10, 75, 10, 10);
    CompoundBorder border   = new CompoundBorder(matteBorder, emptyBorder);

    JPanel userNameArea     = new JPanel();
    userNameArea.setLayout(new FlowLayout(FlowLayout.LEFT, 0, 0));
    userNameArea.setBounds(0, 35, Engine.screenX, 50);
    userNameArea.setBorder(border);
    userNameArea.setBackground(new Color(255, 255, 255, 70));

    JLabel nameLabel        = new JLabel();
    nameLabel.setText("Enter Your Username: ");

    nameInput = new JTextField();
    nameInput.setForeground(Color.black);
    nameInput.setBorder(BorderFactory.createEmptyBorder(0, 5, 0, 0));
    nameInput.setPreferredSize(new Dimension(200, 25));

    errorLabel = new JLabel();
    errorLabel.setText("This is a test label");
    errorLabel.setBorder(BorderFactory.createEmptyBorder(0, 20, 0, 0));
    errorLabel.setPreferredSize(new Dimension(200, 25));
    errorLabel.setAlignmentX(JLabel.LEFT_ALIGNMENT);

    userNameArea.add(nameLabel);
    userNameArea.add(nameInput);
    userNameArea.add(errorLabel);


    return userNameArea;
}

private static JPanel createMainArea() {

    JPanel resetCreatePanel = new JPanel(new GridLayout(1, 2));
    resetCreatePanel.setPreferredSize(new Dimension(300, 30));
    resetCreatePanel.setBackground(Color.black);

    create  = new JButton("Create Character");
    create.setBorder(BorderFactory.createLineBorder(Color.decode("#171717")));
    create.setFont(new Font("Dialog", 1, 11));
    create.setBackground(Color.black);
    create.setForeground(Color.white);
    create.setFocusPainted(false);
    create.setContentAreaFilled(false);
    create.addActionListener(new ActionListener() {

        @Override
        public void actionPerformed(ActionEvent arg0) {
            if(!errorLabel.getText().isEmpty()) {
                errorLabel.setText("");
            } else {
                Engine.p_parser.parseCharacterCreation(nameInput, errorLabel);
            }
        }
    });

    resetCreatePanel.add(create);


}

}

// Engine

public class Engine {
    public static PlayerParser p_parser;
    public Engine() {
        p_parser = new PlayerParser();

    }
}

We'd have to see the code that's doing the parse to say why it's doing something unexpected during the parse, wouldn't we? — Nathaniel Waisbrot, Jun 08 '13 at 20:02
OK `parseCharacterSelection` looks fine. The two lines you post about creating JLabel aren't valid; can you post the actual context for `label = new JLabel()`? — Nathaniel Waisbrot, Jun 08 '13 at 20:13
you say it happens when you click the button. can you show the code that runs after the button is clicked ? code of actionPerformed method and every other method that is called from that code (if therere are) — , Jun 08 '13 at 20:14
@user2444217 you really have the `JLabel` declaration on the line immediately preceding where you initialize it? I can't compile that code. — Nathaniel Waisbrot, Jun 08 '13 at 20:29
@NathanielWaisbrot so, it's part of a class, and the class has a method which creates the JLabel. I wanted to minimize the code I put here, so I cut some parts out which I thought wouldn't affect the problem. — user2444217, Jun 08 '13 at 20:36
Your problem is that you say you keep creating new JLabels. So the code where you call `new JLabel()` is the most important part of your questions. — Nathaniel Waisbrot, Jun 08 '13 at 20:37
@NathanielWaisbrot I made another edit, that has the complete code for the Jlabel — user2444217, Jun 08 '13 at 20:55

score 2 · Answer 1 · answered Jun 09 '13 at 02:04

2

Thanks everyone for the help. The "problem" was that the JPanel that the components were sitting on had a semi-transparent background. And JComponents with transparency get messed up somehow, which made it appear like there are multiple labels being created. But it works fine without transparency.

answered Jun 09 '13 at 02:04

user2444217

581
2
7
16

Thanks for providing closure. :-) What a pain to debug! – Nathaniel Waisbrot Jun 09 '13 at 14:47

java parsing data from component

1 Answers1