Adding a mouseListener to a component drawn with the paintComponent method

Question

I'm trying to add a mouseListener to each Jlabel I create then pass them onto paintComponent.

  private List<JLabel> createTiles (){

    int x = 10;
    int y = 0;
    List<JLabel> tiles = new ArrayList<>();

    //Number of tiles painted
    for (Integer i : gameModelHandle.numbersToDigits()) {

        JLabel tile = new JLabel("" + i, JLabel.CENTER);
        tile.setSize(new Dimension(140, 140));
        tile.setFont(tile.getFont().deriveFont(45f));
        tile.setLocation(x, y);
        tile.addMouseListener(new MouseAdapter() {
            @Override
            public void mouseClicked(MouseEvent e) {

                GameModel.currentSum(i);
                changeColour();
            }

            @Override
            public void mouseReleased(MouseEvent e) {

                if (getBounds().intersects(tile.getBounds())){

                    int number = gameModelHandle.combineDigits(i, Integer.parseInt(tile.getText()));
                    GameModel.currentSum(number);
                }
            }
        });

        tiles.add(tile);
        x+=150;
    }
    return tiles;
}

As you can see, the number of tiles is never the same which is why I can't create them manually; I have a loop for that.

I paint them like so :

  protected void paintComponent(Graphics g) {
    super.paintComponent(g);

    this.removeAll();

    for (JLabel i : createTiles()) {

        g.setColor(tileColours[activeColourIndex]);
        g.fillRoundRect(i.getX(), i.getY(), i.getWidth(), i.getHeight(), 20, 20);
        this.add(i);
    }

    revalidate();
}

And it works, the problem is that my mouseListeners don't seem to work at all. I tried debugging and never got to the mouseClick method.

Any input or guidance would be appreciated.

Answer 1

You don't need to create JLabels inside your paintComponent over and over. Create it once and keep reusing the list of labels for updating them. I was able to create a working example and it seems to be working fine.

The mouse handler is working too.

Here is what I have. Take a look. I had to remove unnecessary parts and tweak the code for compiling and getting it up and running.

public class PaintComponentMouseListener extends JPanel {
    private static final long serialVersionUID = -4235693652966961963L;
    private List<JLabel> tiles;

    private List<JLabel> createTiles() {
        if(tiles == null) {
            tiles = new ArrayList<>();
            int x = 10;
            int y = 0;

            // Number of tiles painted
            for(int i=1;i<=9;i++) {
                String btn = "" + i;
                JLabel tile = new JLabel(btn, JLabel.CENTER);
                tile.setSize(new Dimension(140, 140));
                tile.setFont(tile.getFont().deriveFont(45f));
                tile.setLocation(x, y);
                tile.addMouseListener(new MouseAdapter() {
                    @Override
                    public void mouseClicked(MouseEvent e) {
                        System.out.println("Clicked on button: " + btn);
                    }
                });

                tiles.add(tile);
                x += 150;
            }
        }
        return tiles;
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        this.removeAll();
        for (JLabel i : createTiles()) {
            g.setColor(Color.CYAN);
            g.fillRoundRect(i.getX(), i.getY(), i.getWidth(), i.getHeight(), 20, 20);
            this.add(i);
        }

        revalidate();
    }

    private void start() {
        JFrame frame = new JFrame("Hello");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        this.setLayout(new GridLayout(3, 3));
        frame.setContentPane(this);
        frame.setSize(500, 500);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(()->{
            new PaintComponentMouseListener().start();
        });
    }

}

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Hope this helps!