Develop Reference

MouseAdapter not working

I have a problem with java 7/8 under Ubuntu 15.04. I participate on a project, that's been up for 4 years now, so fixing things in there might be a bigger problem. Nevertheless: When I started using Ubuntu 15.04 the MouseListener stopped working. I minimized the problem to make clear, what I mean:
public class MenuGui {
public MenuGui() {
final JFrame frame = new JFrame("");
JMenuBar bar = new JMenuBar();
JMenu m1 = new JMenu("Start");
JMenuItem i11 = new JMenuItem("Action");
i11.addMouseListener(new MouseAdapter()
{
public void mousePressed(MouseEvent e) {
JOptionPane.showConfirmDialog(frame, "hi");
}
});
m1.add(i11);
bar.add(m1);
frame.setJMenuBar(bar);
frame.setVisible(true);
}
public static void main(String[] args){
new MenuGui();
}
}
When I run this example on my machine, the Menu is on the gnome menu, but clicking the Menu Entry does not do anything. Question now is: is there a way to easily place the menu back to the actual jframe or even better is there a fix for ubuntu 15.04?
Running it as root places the menu back to the jframe and it starts working just fine.

Without being an expert on JMenuItems, I think you need an ActionListener, NOT listen to mouse events.

Java applet game does not work on Macs, even though it does work on PCs

I made a game that is based in a jpanel. When I add the jpanel to a jframe, it works fine on both pc's and macs.
here is the class where I add the jpanel to the jframe:
import javax.swing.JFrame;
public class Start{
public static void main(String[] args){
JFrame f = new JFrame("Rocks");
f.setSize(600,500);
f.setResizable(false);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Board b = new Board();
f.add(b);
f.setVisible(true);
}
}
However, when I add this jpanel to a japplet, it still works perfectly on pc's, but not on macs. In the eclipse applet tester, the first screen paints, but it doesn't accept keyboard input to start the game. In any browser/html page though, the game doesn't seem to load at all, and when I open the java console of chrome I see no errors.
here is the class where I add the jpanel to the japplet
import javax.swing.JApplet;
public class rockAppletStart extends JApplet{
public void init(){
Board b;
b = new Board();
add(b);
b.focus();
}
public void start(){}
public void stop(){}
public void destroy(){}
}
I would appreciate any help that could be offered, and I'm willing to provide more information if necessary. I could even provide the other classes of the game, but there very long and messy, and I'd rather not unless necessary.
The applet version of the game can be found here at gamejolt.com, if you feel like testing it out. If you have a pc, it should work fine, but with a mac it won't.
** edit **
here you can download the .jar file of all the classes and resources. Feel free to use the files to test out your solution yourself if you want... Otherwise, Ill have access to a mac on Tuesday and I will test all solutions then.
http://dl.dropbox.com/u/18832480/Rocks_Source_file.jar

This is just a SWAG, but since Swing threading issues can often cause pernicious, unpredictable and hard to detect errors, what if you create your applet in a thread-safe manner? i.e.,
public void init() {
try {
javax.swing.SwingUtilities.invokeAndWait(new Runnable() {
public void run() {
createGUI();
}
});
} catch (Exception e) {
System.err.println("createGUI didn't successfully complete");
}
}
private void createGUI() {
Board b;
b = new Board();
getContentPane().add(b);
b.focus()
}

The JApplet is stealing the focus from the Board. To prevent it, add the following to the end of your init() method:
setFocusable(false);

Flashing JFrame

I would like to create a JFrame with two specifal features:
JFrame should not grab focus while maximized from minimized state.
When a JFrame created or became maximized from minimized state, it should flash in the Windows bar until a user will grant a focus to it. (like as in ICQ clients ).
Does anybody know how the second requirement can be implemented?
Little self-explained example:
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
public class JFrameTest {
private static JFrame childFrame;
public static Container getParentContentPane() {
JPanel panel = new JPanel();
JButton button = new JButton("Create\\Restore child frame");
button.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e) {
createOrRestoreChildFrame();
}
});
panel.add(button);
return panel;
}
private static void createOrRestoreChildFrame() {
if (childFrame == null) {
childFrame = new JFrame("Child Frame");
childFrame.setLocation(200, 200);
childFrame.add(new JLabel("Child Frame"));
childFrame.pack();
setChildFrameVisible();
} else {
setChildFrameVisible();
}
}
private static void setChildFrameVisible() {
childFrame.setFocusableWindowState(false);
childFrame.setVisible(true);
flashInWindowsBar(childFrame);
childFrame.toFront();
childFrame.setFocusableWindowState(true);
}
/**
* Should Make child frame flash in Windows bar.
* Currently, it does not work for me.
* Could anybody help me to fix this please? )
*/
private static void flashInWindowsBar(JFrame childFrame) {
childFrame.setState(JFrame.ICONIFIED);
childFrame.toFront();
}
private static void createAndShowGUI() {
JFrame parentFrame = new JFrame("JFrame Demo");
parentFrame.setLocation(100, 100);
parentFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
parentFrame.setContentPane(getParentContentPane());
parentFrame.pack();
parentFrame.setVisible(true);
}
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}
Thanks!

The following code worked for me exactly as you described:
f.setState(JFrame.ICONIFIED);
f.toFront();
f is a JFrame.

Unfortunately, this isn't something that you can do natively under any Java platform. Anyone who manages to get it working by using the kind of 'trickery' that you've shown, will be disappointed to find that it is unlikely to work on another version of Windows, or even another computer with the same version of Windows. The only times I've ever seen a Java window flash is due to some glitch in Swing when minimizing all windows to the taskbar.
As this article on making Java applications feel native shows, it's the same on Mac OS.
Your best bet is to use the techniques described in the above article to make a JNI which does the Windows API call, or get a license for JNIWrapper (search for it) which does it all for you (best option if you are making a commercial app, or making it for a client who is willing to pay for such a feature). It looks like you can get a 30-day trial for that.
The only other thing I could suggest is create a poor-man's equivalent of a pop-up notification system. When you want to alert the user, create a Frame without a border, put it in the bottom-right corner of the screen, make it non-focusable and show it for a brief period of time.

The JPanel does not flash. Try it instead of JFrame.

Desktop application - how do I dynamically create and destroy forms

I'm creating a small crypto app for the desktop using java.
I'm using JFrames (import javax.swing.JFrame) with Oracle
JDeveloper 11g under Linux.
I want to have a "welcome" form/frame where users can choose
their encryption method, and then on choosing the method,
I want to dynamically create the appropriate form for the
chosen encryption method and also destroy/free/dispose() of
the welcome form. When the user has finished their encrypting,
they should close the frame/form (either by clicking on the
x at the top right - or using the Exit button or by any
method) and the welcome frame should be dynamically recreated
and appear.
I've tried various things - btnEncode_actionPerformed(ActionEvent e)
then this.dispose() - and I've fiddled with this_windowClosed(WindowEvent e)
and dispose(), but nothing seems to work.
Even a workaround using setVisibl(true/false) would be acceptable at
this stage - this has been wrecking my head all day. It's very
easy to do in Delphi!
TIA and rgs,
Paul...

something like this usually does the trick: (Note I haven't tested this)
public class WelcomeMsg extends JFrame
.
.
.
public void btnContinue_actionPerformed(ActionEvent e)
{
this.dispose();
SwingUtilities.invokeLater(new Runnable(){ new JFrameAppropriateWindow(args) });
}
where btnContinue is the Continue button on your welcome form and JFrameAppropriateWindow is the next frame you would like to show depending on the user's choice. Args are any arguments you need to pass.
When you are ready, you can simply dispose the current frame and relaunch an instance of WelcomeMsg

I put together this simple example for creating and displaying a panel depending on a user choice.
public class Window extends JFrame {
public Window() {
this.setLayout(new BorderLayout());
JComboBox encryptionCombobox = new JComboBox();
encryptionCombobox.addItem("foo");
encryptionCombobox.addItem("bar");
//...
encryptionCombobox.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
// find choices and the correct panel
JPanel formPanel = new JPanel();
formPanel.setOpaque(true);
formPanel.setBackground(Color.RED);
//...
Window.this.add(formPanel, BorderLayout.CENTER);
Window.this.validate();
Window.this.repaint();
}
});
add(encryptionCombobox, BorderLayout.NORTH);
}
public static void main(String[] args) {
new Window().setVisible(true);
}
}
When I come to think about it, you should probably use a CardLayout instead, which allows you to switch between different panels (cards).

Making a Java panel fullscreen

How would you make a JComponent (panel, frame, window, etc.) fullscreen, so that it also overlaps everything on the screen including the windows start bar?
I don't want to change the resolution or anything with the graphics device like bitdepth etc, I just want to overlap everything else.

Check out this tutorial describing Java's Full-Screen mode API.
Example code (taken from the tutorial). Note that the code operates on a Window so you would need to embed your JPanel with a Window (e.g. JFrame) in order to do this.
GraphicsDevice myDevice;
Window myWindow;
try {
myDevice.setFullScreenWindow(myWindow);
...
} finally {
myDevice.setFullScreenWindow(null);
}

You can try some of the codes in this page, allowing a container to fill the screen (so it is not a solution for an individual component, but for a set of components within a container like a JFrame)
public class MainWindow extends JFrame
{
public MainWindow()
{
super("Fullscreen");
getContentPane().setPreferredSize( Toolkit.getDefaultToolkit().getScreenSize());
pack();
setResizable(false);
show();
SwingUtilities.invokeLater(new Runnable() {
public void run()
{
Point p = new Point(0, 0);
SwingUtilities.convertPointToScreen(p, getContentPane());
Point l = getLocation();
l.x -= p.x;
l.y -= p.y;
setLocation(l);
}
});
}
...
}

You need to use the following API: http://java.sun.com/docs/books/tutorial/extra/fullscreen/index.html
Going full screen isn't as simple as making a large panel, you need to look into the underlying OS graphics. But your JPanel code should translate just fine.

I needed to search a lot, to do the same. Here is completely a working version of it by steps, so that i can find it later also, and use it.
Step 1: create a file called fullscreen.java
Step 2: copy this code and paste it as it is:
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class fullscreen extends Window
{
private Button button;
public fullscreen()
{
super(new Frame());
button = new Button("Close");
button.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
System.exit(0);
}
});
setLayout(new FlowLayout());
add(button);
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
setBounds(0,0,screenSize.width, screenSize.height);
}
public static void main(String[] args)
{
// This will take over your whole screen tested and works in my:
// Fedora 12/13/14
// CentOS 5.0
// if this works for you, in other platforms, please leave a comments which OS it worked.
// happy coding!
new fullscreen().setVisible(true);
}
}
Step 3: compile the code and run
Done.

If I were you I would try to make Java not draw the border of the Jframe, then make it take all the screen.
import java.awt.GraphicsEnvironment;
import java.awt.Rectangle;
import javax.swing.JFrame;
public class FenNoBorder extends JFrame {
public FenNoBorder () {
setUndecorated(true);
setVisible(true);
GraphicsEnvironment graphicsEnvironment=GraphicsEnvironment.getLocalGraphicsEnvironment();
Rectangle maximumWindowBounds=graphicsEnvironment.getMaximumWindowBounds();
setBounds(maximumWindowBounds);
}
}