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javamacosswingjoptionpane

Getting JOptionPane.showConfirmDialog() to function on Mac OSX

I am having trouble getting message boxes and to a degree dialog boxes to show/function properly in Mac (v10.9.5).

I just updated the JRE and JDK to the latest version (8u31). A "java -version" from a terminal window shows that I am indeed using 8u31. (I was previously using 8u20, which exhibited the same behavior.)

The code below works perfectly in Windows and a couple of different versions of Linux that I tested, no issues. I just have issues on a Mac. I streamlined my code, which is SWT based, but this example uses Swing, to the following:

package myTest;

import java.awt.Dimension;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;

public class EntryCode
{
    public static EntryCode oEntryCode;

    public EntryCode()
    {
        // TODO Auto-generated constructor stub
    }

    public static void main(String[] args)
    {
        oEntryCode = new EntryCode();

        oEntryCode.open();
    }

    public void open()
    {
        JPanel panel = new JPanel();
        panel.setMinimumSize(new Dimension(200,200));

        JFrame frame = new JFrame("JOptionPane showMessageDialog component example");
        System.out.println("open(): entry - With frame");
        JOptionPane.showConfirmDialog(frame, "Wow, works on the Mac!", "Inside open()", JOptionPane.YES_NO_OPTION);
        System.out.println("Point 1");

        System.exit(0);
    }
}

I see the first system out line, and the code hangs on the message box request. In the real code, I simply use a null as the first argument. The original version of this test code used a null too, just I was experimenting with specifying a component. I thought that might be the problem. It is not.

When displaying SWT dialog boxes, there is a tendency that clicking on a button will hang the interface. The hang is somewhere between the button being depressed and the event handler firing. The event handler never fires.

I did not include a dialog box here. I figure that since my confirmation/message box exhibits the same problem that solve one, get the other for free.

I did a search on Google for displaying java applications on a Mac, but nothing turned up.

I would think that updating the JRE/JDK to the latest version would solve any OS related issues.

I compile the code to a jar and use the following to run from a terminal window. I to press Ctrl+C to quite the hung app.

java -XstartOnFirstThread -jar myTest.jar

Thoughts?

UPDATE:

I deleted the original update but am leaving the original question, now that I understand the problem better.

The real problem is how to initiate a proper Mac OSX Cocoa restriction friendly SWT application, which uses dialog and message boxes. (To the best of my knowledge, the only way to display message boxes is to use JOptionPane.show*, which is a Swing thing, thereby sort of mixing Swing and SWT.

It is interesting to note that the problem always relates to buttons, be it on a dialog box (a purely SWT implementation) or message boxes. In the former, the issue is a hang calling the event handler and the latter displaying a message box (null first argument, as no Swing frame exists in a SWT application).

Solution

  • Not quite sure if this might be the error since I can't test it on my Mac at the moment. But you never setting visibility of the JFrame to true. When you pass the frame as a parameter to the JOptionPane the pane tries to show the pane in the frame.

    So try : 

     public void open()
{
    JFrame frame = new JFrame("JOptionPane showMessageDialog component example");
    System.out.println("open(): entry - With frame");
    frame.setSize(300,300);
    frame.setLocationRelativeTo(null);
    frame.setVisible(true);

    JOptionPane.showConfirmDialog(frame, "Wow, works on the Mac!", "Inside open()", JOptionPane.YES_NO_OPTION);
    System.out.println("Point 1");

    System.exit(0);
}

    Also why do you create the JPanel the panel is never used as far as I can see ?

    Since the frame is not visible this could cause problems. Just a guess... This would also explain why it looks like your application is "freezing". Its because it is waiting for you to make the selection in your JOptionPane but you can't make that selection because you can't see the JOptionPane.

    I know you wrote you also tried with passing null as argument but I could think this could also cause problems when there is no other JFrame shown. As i said just a guess. Just try it out and come back here to provide further information.

    EDIT Just tested and looks like your code is fine. Your error has to lie in your mac or java setup.

    EDIT 2 I think I found your answer. Looks like the startOnFirstThread is the problem here. I just tested via javac and java on command line. Have a look at this:

    Swing stops working, because -XstartOnFirstThread implies that that
    someone else (very likely the SWT) is going to come around, and start
    pumping the event loop on thread 0 with CFRunLoop or the like

    This could explain why your JOptionPane struggles to show up. (Taken from: here

    Also a bit older but describes your problem:

    The AWT problems generally come down to which thread the jvm was started on. When using the java launcher (as pde does) on Mac, java by default starts on the second thread (which is what AWT wants) unless you specify -XstartOnFirstThread (which is what SWT wants). (https://bugs.eclipse.org/bugs/show_bug.cgi?id=212617)