Making a JFileChooser select the text of the file name but not the extension

Question

I'd like the text in the file name field of the JFileChooser save dialog to select just the file name and not the extension.

I currently have this:

And want it to look like this:

This is a simple change, but one that makes saving a file much easier, in my opinion, since the user can start typing the file name right away without erasing the extension accidentally.

I know I can forcefully add the extension if it's missing, but I'd rather not do this because the extension isn't mandatory and I don't feel it should be enforced.

So, is there any way I could achieve this?

Applewhite

I don't know the answer but it is a good question, I will look at see what I can find. – Daybook

Answer 1

The API does not offer that directly but one simple way to do it is to scan the component hierarchy, looking for a JTextField and then change the selection of that textfield.

Here is an example of that solution:

import java.awt.Component;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;

import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;

public class TestJFileChooser {

    public TestJFileChooser() {

    }

    protected void initUI() {
        JFrame frame = new JFrame(TestJFileChooser.class.getSimpleName());
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        final JButton button = new JButton("Click me");
        button.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                JFileChooser chooser = new JFileChooser();
                chooser.setSelectedFile(new File(chooser.getCurrentDirectory(), "save.dat"));
                final JTextField textField = getTexField(chooser);
                if (textField != null) {
                    SwingUtilities.invokeLater(new Runnable() {
                        @Override
                        public void run() {
                            String text = textField.getText();
                            if (text != null) {
                                int index = text.lastIndexOf('.');
                                if (index > -1) {
                                    textField.setSelectionStart(0);
                                    textField.setSelectionEnd(index);
                                }
                            }
                        }
                    });
                }
                chooser.showSaveDialog(button);
            }

            private JTextField getTexField(Container container) {
                for (int i = 0; i < container.getComponentCount(); i++) {
                    Component child = container.getComponent(i);
                    if (child instanceof JTextField) {
                        return (JTextField) child;
                    } else if (child instanceof Container) {
                        JTextField field = getTexField((Container) child);
                        if (field != null) {
                            return field;
                        }
                    }
                }
                return null;
            }
        });
        frame.add(button);
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                TestJFileChooser fc = new TestJFileChooser();
                fc.initUI();
            }
        });
    }
}

Snip

A bit heavier than I was hoping for, but it works like a charm. Thanks! – Applewhite

Answer 2

it seems that it's not possible to configure this on the default component,

i guess you'll have to extend it, this tutorial will help you :

https://today.java.net/pub/a/today/2007/02/22/how-to-write-custom-swing-component.html

Fredenburg

Please avoid posting Link-only answers. This is not very helpful and your link may get broken at some point, loosing all the relevant information. – Snip

Answer 3

I believe you can write a custom JFileChooser by extending com.sun.java.swing.plaf.windows.WindowsFileChooserUI and override its setFileName() method.

Olodort

But the user seems to be on Linux (from the L&F of his screenshot). Anyway, that's not portable at all. I would not go down that road. – Snip

@GuillaumePolet Yes you are right. Its not portable and will be useful only if on Windows OS. – Olodort