Question

I have a JFileChooser that lets users choose an image for themselves. I want to limit the images they can choose to ones with square dimensions, for example –

width and height both 50

width and height both 75, etc…

So when they select an image with the JFileChooser and click ‘Open’ I need to validate the image size and if it doesn’t have square dimensions I need to present the user with a dialog informing them “The image must have the same width and height”.

I’m just learning swing so I don’t know how to do this. Any ideas on how to do this? Is there a way of hooking the “Open” button’s event handler?

Answer 1

You can hide all images that do not confirm to the rules with an implementation of a FileFilter:

JFileChooser fileChooser = new JFileChooser(new File(filename));
fileChooser.addChoosableFileFilter(new MyFilter());

// Open file dialog.
fileChooser.showOpenDialog(frame);
openFile(fileChooser.getSelectedFile());

class MyFilter extends javax.swing.filechooser.FileFilter {
    public boolean accept(File file) {
        // load the image
        // check if it satisfies the criteria
        // return boolean result
    }
}