Re: Using JFileChooser from modal dialog

From:
"John B. Matthews" <nospam@nospam.invalid>
Newsgroups:
comp.lang.java.gui
Date:
Wed, 11 Sep 2013 06:51:42 -0400
Message-ID:
<nospam-8378C0.06514111092013@news.aioe.org>
In article <c713853a-73c4-4bf3-9e9a-7abf98a52677@googlegroups.com>,
 gosmith666@gmail.com wrote:

On Thursday, February 9, 2012 12:59:29 PM UTC-5, FredK wrote:

How do I pop up and use a JFileChooser from a modal dialog?

I find the methods setModalExclusionType and setModalityType,
but they are methods of Window and Dialog; when I pop the file
chooser using showDialog(), how do I get access to the window
or frame used to display it so that I can set its modality?

[...]

        aFrame.setAlwaysOnTop(true);

[...]

This makes sure the File Chooser is Modal and AlwaysOnTop


I've addressed some issues with the fragment shown in the complete
example below:

- Rather than multiple frames, use a modeless dialog for the
chooser.

- Consider AbstractAction to encapsulate functionality.

- "Note: some platforms might not support always-on-top windows." [1]

- Swing GUI objects should be constructed and manipulated _only_ on
the event dispatch thread. [2]

- Instead of getAbsolutePath(), use the FileReader constructor that
accepts a file [not shown].

SSCCE:

import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.io.File;
import javax.swing.AbstractAction;
import javax.swing.JDialog;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JTextArea;

public class Test {

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                new Test().display();
            }
        });
    }

    private void display() {
        JFileChooser chooser = new JFileChooser();
        chooser.setDialogType(JFileChooser.OPEN_DIALOG);
        chooser.setApproveButtonText("Select");
        
        JTextArea text = new JTextArea(16, 40);
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setLocationByPlatform(true);
        f.add(text, BorderLayout.CENTER);
        f.pack();
        f.setVisible(true);

        JDialog d = new JDialog();
        d.add(chooser, BorderLayout.CENTER);
        d.pack();
        d.setLocationRelativeTo(null);
        d.setAlwaysOnTop(true);
        d.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        chooser.addActionListener(new SelectAction(chooser, text));
        d.setVisible(true);
    }

    private static class SelectAction extends AbstractAction {

        private JFileChooser chooser;
        private JTextArea text;

        public SelectAction(JFileChooser chooser, JTextArea text) {
            this.chooser = chooser;
            this.text = text;
        }

        @Override
        public void actionPerformed(ActionEvent e) {
            if ((e.getActionCommand())
                    .equals(JFileChooser.APPROVE_SELECTION)) {
                File file = chooser.getSelectedFile();
                text.append(file.getPath() + "\n");
            }
        }
    }
}

[1] <http://docs.oracle.com/javase/7/docs/api/java/awt/Window.html>
[2] <http://docs.oracle.com/javase/tutorial/uiswing/concurrency/initial.html>

--
John B. Matthews
trashgod at gmail dot com
<http://sites.google.com/site/drjohnbmatthews>

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