Alfonso Sanz

Thanks Rob for your prompt and expert answer. Indeed seemed to be linked to focus loss.

Hello,

taking as example the code from:
https://docs.oracle.com/javase/tutorial/uiswing/examples/components/index.html#ListDemo,

being like this:

import java.awt.*; import java.awt.event.*; import javax.swing.*; import javax.swing.event.*; /* ListDemo.java requires no other files. */ public class ListDemo extends JPanel                      implements ListSelectionListener {    private JList list;    private DefaultListModel listModel;    private static final String hireString = "Hire";    private static final String fireString = "Fire";    private JButton fireButton;    private JTextField employeeName;    public ListDemo() {        super(new BorderLayout());        listModel = new DefaultListModel();        listModel.addElement("Jane Doe");        listModel.addElement("John Smith");        listModel.addElement("Kathy Green");        //Create the list and put it in a scroll pane.        list = new JList(listModel);        list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);        list.setSelectedIndex(0);        list.addListSelectionListener(this);        list.setVisibleRowCount(5);        JScrollPane listScrollPane = new JScrollPane(list);        JButton hireButton = new JButton(hireString);        HireListener hireListener = new HireListener(hireButton);        hireButton.setActionCommand(hireString);        hireButton.addActionListener(hireListener);        hireButton.setEnabled(false);        fireButton = new JButton(fireString);        fireButton.setActionCommand(fireString);        fireButton.addActionListener(new FireListener());        employeeName = new JTextField(10);        employeeName.addActionListener(hireListener);        employeeName.getDocument().addDocumentListener(hireListener);        String name = listModel.getElementAt(                              list.getSelectedIndex()).toString();        //Create a panel that uses BoxLayout.        JPanel buttonPane = new JPanel();        buttonPane.setLayout(new BoxLayout(buttonPane,                                           BoxLayout.LINE_AXIS));        buttonPane.add(fireButton);        buttonPane.add(Box.createHorizontalStrut(5));        buttonPane.add(new JSeparator(SwingConstants.VERTICAL));        buttonPane.add(Box.createHorizontalStrut(5));        buttonPane.add(employeeName);        buttonPane.add(hireButton);        buttonPane.setBorder(BorderFactory.createEmptyBorder(5,5,5,5));        add(listScrollPane, BorderLayout.CENTER);        add(buttonPane, BorderLayout.PAGE_END);    }    class FireListener implements ActionListener {        public void actionPerformed(ActionEvent e) {            //This method can be called only if            //there's a valid selection            //so go ahead and remove whatever's selected.            int index = list.getSelectedIndex();            listModel.remove(index);            int size = listModel.getSize();            if (size == 0) { //Nobody's left, disable firing.                fireButton.setEnabled(false);            } else { //Select an index.                if (index == listModel.getSize()) {                    //removed item in last position                    index--;                }                list.setSelectedIndex(index);                list.ensureIndexIsVisible(index);            }        }    }    //This listener is shared by the text field and the hire button.    class HireListener implements ActionListener, DocumentListener {        private boolean alreadyEnabled = false;        private JButton button;        public HireListener(JButton button) {            this.button = button;        }        //Required by ActionListener.        public void actionPerformed(ActionEvent e) {            String name = employeeName.getText();            //User didn't type in a unique name...            if (name.equals("") || alreadyInList(name)) {                Toolkit.getDefaultToolkit().beep();                employeeName.requestFocusInWindow();                employeeName.selectAll();                return;            }            int index = list.getSelectedIndex(); //get selected index            if (index == -1) { //no selection, so insert at beginning                index = 0;            } else {           //add after the selected item                index++;            }            listModel.insertElementAt(employeeName.getText(), index);            //If we just wanted to add to the end, we'd do this:            //listModel.addElement(employeeName.getText());            //Reset the text field.            employeeName.requestFocusInWindow();            employeeName.setText("");            //Select the new item and make it visible.            list.setSelectedIndex(index);            list.ensureIndexIsVisible(index);        }        //This method tests for string equality. You could certainly        //get more sophisticated about the algorithm.  For example,        //you might want to ignore white space and capitalization.        protected boolean alreadyInList(String name) {            return listModel.contains(name);        }        //Required by DocumentListener.        public void insertUpdate(DocumentEvent e) {            enableButton();        }        //Required by DocumentListener.        public void removeUpdate(DocumentEvent e) {            handleEmptyTextField(e);        }        //Required by DocumentListener.        public void changedUpdate(DocumentEvent e) {            if (!handleEmptyTextField(e)) {                enableButton();            }        }        private void enableButton() {            if (!alreadyEnabled) {                button.setEnabled(true);            }        }        private boolean handleEmptyTextField(DocumentEvent e) {            if (e.getDocument().getLength() <= 0) {                button.setEnabled(false);                alreadyEnabled = false;                return true;            }            return false;        }    }    //This method is required by ListSelectionListener.    public void valueChanged(ListSelectionEvent e) {        if (e.getValueIsAdjusting() == false) {            if (list.getSelectedIndex() == -1) {            //No selection, disable fire button.                fireButton.setEnabled(false);            } else {            //Selection, enable the fire button.                fireButton.setEnabled(true);            }        }    }    /**     * Create the GUI and show it.  For thread safety,     * this method should be invoked from the     * event-dispatching thread.     */    private static void createAndShowGUI() {        //Create and set up the window.        JFrame frame = new JFrame("ListDemo");        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);        //Create and set up the content pane.        JComponent newContentPane = new ListDemo();        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();            }        });    } }



When changing:

       employeeName = new JTextField(10);

by:

       try { employeeName = new JFormattedTextField(new MaskFormatter("UUUUUUUU")); } catch (ParseException e) { e.printStackTrace(); }


behaviour changes so much...

This is:

1) Hire button must be pressed twice instead of one to add a new elemet to JList.
2) If press Hire once the JFormattedTextField is emptied, it shows an element.


I would like to have the advantages of original version but having the Formatter as well.

What changes should I do?

Thanks in advance!!

Great!

thank you all!

Hi Iuliana!

First of all, congratulations for the second edition.

I would like to know if the book covers AOP.

Best Regards.

Thanks Peter for your answer. I did not know the book.
BR

Hello Craig,

My question is about the certificate:

does this book cover the whole matters of the certificate? Could be used as a guide to take the exam  with no taking the Pivotal course ?

does it worth get the certification?

Thanks in advance.

Hi!

Under "Understanding Views"

The text says: "... Both of these methods can throw a checked IOException, such as when the view class type is unsupported."  

But public static <V extends FileAttributeView> V getFileAttributeView(Path path, Class<V> type, LinkOption... options) does not throw any IOException.

Regars,

Hi!

I am sure it will be a great book and I hope there will be lots of test-like questions to practice!

Congrats to Sierra, Bates and Robson!

great and very very instructive answer!! I learnt a lot on your explanation. Thanks a lot John Damien Smith!!

PD: Indeed I had already used AudioClip.

Thanks again!

Great post and great book! Thanks Knute Snortum.

For the time being I am just invertigating how to play sounds and still not sure whethrt to use Clip.loop() or Mediaplayer.play(). It's not about JavaFX.

I also consider using "aplay" system call cause so far this approach is working best on Linux, where as I said above, two instanciations of MediaPlayer give sometimes MediaException.

In anycase, I'll consider to buy the book you recommend me. It looks quite interesting.

Thanks again.

Knute Snortum wrote:Instead of
for(int i=0;i<1000000;i++) { System.out.println(i); } // delay what about Thread.sleep(1000); // one second

That may not be the best way of getting a delay in JavaFX, though.

Thread.sleep() has the same effect. Both sounds at a time.

One more question:

Here is the second piece of code:

import java.io.File; import javafx.application.Application; import javafx.scene.media.Media; import javafx.scene.media.MediaPlayer; import javafx.stage.Stage; public class Clip extends Application {        @Override        public void start(Stage primaryStage) {            Media hit = new Media(new File("beep.wav").toURI().toString());            MediaPlayer player = new MediaPlayer(hit);            Media hit2 = new Media(new File("beep2.wav").toURI().toString());            MediaPlayer player2 = new MediaPlayer(hit2);            player.play();            for(int i=0;i<1000000;i++) { System.out.println(i); } // delay             player2.play();                    }        public static void main(String[] args) {             launch(args);        }    }

In spite of the delay, both sounds are being played in parallel. Why? How to make a real "gap"?

By the way... under Windows everything runs conveniently, but under RHEL,  when creating            MediaPlayer player2 = new MediaPlayer(hit2); looks like randomly I get MediaException in init(). Enybody knows??

Thanks in advance.

That's just what I needed! Thanks you Stephan van Hulst!

I'll give it a try.
Thanks!

I have also added Thread.sleep() with a time greater than the beep duration as parameter in between but only one os played.