CODEWITHSUNDEEP
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SnappleCaptain
SnappleCaptain

Reputation: 43

JLabel containing an ImageIcon won't repaint

I'm writing an application that creates a deck of cards in a random order and when a button is pressed moves the top card to the bottom and shows the new top card. (It's to simulate a Planechase deck to those familiar with Magic: the Gathering.) When the button is pressed it is properly cycling through the image files, but when I assign an image to a JLabel with an ImageIcon I can't get the JLabel to refresh with the new image. Here's the code I'm using to refresh

    nextCardButton.addActionListener(new ActionListener() {
        @Override
        public void actionPerformed(ActionEvent e) {
            planechase.topCardIncrement();
            createCardToDisplay();
        }
    });

planechase is an instance of a class CardDeck which stores the randomized deck and has several methods to shuffle, change cards, etc. topCardIncrement() changes the top card to the next in the list.

    private void createCardToDisplay()
    {
    cardToDisplay = new JLabel(new ImageIcon(planechase.getFolderName() + "\\" + planechase.displayTopCard()));
    }

createCardToDisplay assigns cardToDisplay to an image derived from the folder name of the images and the current file. cardToDisplay is placed within JPanel contentPanel which is placed within JFrame frame. I can't figure out the proper way to repaint/revalidate (I'm not quite clear on what the difference is) my GUI to reflect the updated image. I've confirmed via System.out.println calls that

    planechase.getFolderName() + "\\" + planechase.displayTopCard()

is updating as it should, so I assume that the JLabel is being reassigned properly. What is the proper way to redraw this so that it reflects the new ImageIcon?

Upvotes: 0

Views: 692

Answers (1)

MadProgrammer
MadProgrammer

Reputation: 347334

The code is ambiguous...

The first thing that jumps out at me is...

private void createCardToDisplay()
{
    cardToDisplay = new JLabel(new ImageIcon(planechase.getFolderName() + "\\" + planechase.displayTopCard()));
}

This is creating a new instance of cardToDisplay, but is it been added anywhere? Is the previous instance been removed? There's no context to be certain.

Normally, when you want to change the icon of a JLabel, you would simply call setIcon on the instance of the JLabel...

cardToDisplay.setIcon(new ImageIcon(planechase.getFolderName() + "\\" + planechase.displayTopCard()));

Because this is a bound field, it will trigger a repaint request automatically.

Upvotes: 1

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