A Java JFileChooser example, with ActionEvent, ActionListener, Insets, actionPerformed, showOpenDialog

This is a Java JFileChooser example from Sun Microsystems that shows how to work with a JFileChooser, and also shows related features, including ActionEvent, ActionListener, the actionPerformed and showOpenDialog methods, and more.

(I’ve included it here because I work with Java Swing applications quite a bit, and I want it to be easier to find on my website.)

/**
 * Copyright (c) 2006 Sun Microsystems, Inc. All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * -Redistribution of source code must retain the above copyright notice, this
 *  list of conditions and the following disclaimer.
 *
 * -Redistribution in binary form must reproduce the above copyright notice,
 *  this list of conditions and the following disclaimer in the documentation
 *  and/or other materials provided with the distribution.
 *
 * Neither the name of Sun Microsystems, Inc. or the names of contributors may
 * be used to endorse or promote products derived from this software without
 * specific prior written permission.
 *
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING
 * ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
 * OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MIDROSYSTEMS, INC. ("SUN")
 * AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE
 * AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
 * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST
 * REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL,
 * INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY
 * OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE,
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 * You acknowledge that this software is not designed, licensed or intended
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 */

import java.awt.BorderLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;

import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JDialog;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;

/**
 * SwingFileChooserDemo.java is a 1.4 application that uses these files:
 * images/Open16.gif images/Save16.gif
 */
public class SwingFileChooserDemo extends JPanel implements ActionListener {
  static private final String newline = "\n";

  JButton openButton, saveButton;

  JTextArea log;

  JFileChooser fc;

  public SwingFileChooserDemo() {
    super(new BorderLayout());

    //Create the log first, because the action listeners
    //need to refer to it.
    log = new JTextArea(5, 20);
    log.setMargin(new Insets(5, 5, 5, 5));
    log.setEditable(false);
    JScrollPane logScrollPane = new JScrollPane(log);

    //Create a file chooser
    fc = new JFileChooser();

    //Uncomment one of the following lines to try a different
    //file selection mode. The first allows just directories
    //to be selected (and, at least in the Java look and feel,
    //shown). The second allows both files and directories
    //to be selected. If you leave these lines commented out,
    //then the default mode (FILES_ONLY) will be used.
    //
    //fc.setFileSelectionMode(JFileChooser.DIRECTORIES_ONLY);
    //fc.setFileSelectionMode(JFileChooser.FILES_AND_DIRECTORIES);

    //Create the open button. We use the image from the JLF
    //Graphics Repository (but we extracted it from the jar).
    openButton = new JButton("Open a File...",
        createImageIcon("images/Open16.gif"));
    openButton.addActionListener(this);

    //Create the save button. We use the image from the JLF
    //Graphics Repository (but we extracted it from the jar).
    saveButton = new JButton("Save a File...",
        createImageIcon("images/Save16.gif"));
    saveButton.addActionListener(this);

    //For layout purposes, put the buttons in a separate panel
    JPanel buttonPanel = new JPanel(); //use FlowLayout
    buttonPanel.add(openButton);
    buttonPanel.add(saveButton);

    //Add the buttons and the log to this panel.
    add(buttonPanel, BorderLayout.PAGE_START);
    add(logScrollPane, BorderLayout.CENTER);
  }

  public void actionPerformed(ActionEvent e) {

    //Handle open button action.
    if (e.getSource() == openButton) {
      int returnVal = fc.showOpenDialog(SwingFileChooserDemo.this);

      if (returnVal == JFileChooser.APPROVE_OPTION) {
        File file = fc.getSelectedFile();
        //This is where a real application would open the file.
        log.append("Opening: " + file.getName() + "." + newline);
      } else {
        log.append("Open command cancelled by user." + newline);
      }
      log.setCaretPosition(log.getDocument().getLength());

      //Handle save button action.
    } else if (e.getSource() == saveButton) {
      int returnVal = fc.showSaveDialog(SwingFileChooserDemo.this);
      if (returnVal == JFileChooser.APPROVE_OPTION) {
        File file = fc.getSelectedFile();
        //This is where a real application would save the file.
        log.append("Saving: " + file.getName() + "." + newline);
      } else {
        log.append("Save command cancelled by user." + newline);
      }
      log.setCaretPosition(log.getDocument().getLength());
    }
  }

  /** Returns an ImageIcon, or null if the path was invalid. */
  protected static ImageIcon createImageIcon(String path) {
    java.net.URL imgURL = SwingFileChooserDemo.class.getResource(path);
    if (imgURL != null) {
      return new ImageIcon(imgURL);
    } else {
      System.err.println("Couldn't find file: " + path);
      return null;
    }
  }

  /**
   * Create the GUI and show it. For thread safety, this method should be
   * invoked from the event-dispatching thread.
   */
  private static void createAndShowGUI() {
    //Make sure we have nice window decorations.
    JFrame.setDefaultLookAndFeelDecorated(true);
    JDialog.setDefaultLookAndFeelDecorated(true);

    //Create and set up the window.
    JFrame frame = new JFrame("SwingFileChooserDemo");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    //Create and set up the content pane.
    JComponent newContentPane = new SwingFileChooserDemo();
    newContentPane.setOpaque(true); //content panes must be opaque
    frame.setContentPane(newContentPane);

    //Display the window.
    frame.pack();
    frame.setVisible(true);
  }

  public static void main(String[] args) {
    //Schedule a job for the event-dispatching thread:
    //creating and showing this application's GUI.
    javax.swing.SwingUtilities.invokeLater(new Runnable() {
      public void run() {
        createAndShowGUI();
      }
    });
  }
}