Re: [platform-swt-dev] Display.asyncExec premepts pending events

["Steve Northover" <Steve_Northover@xxxxxxx>]

Thanks Randy.  Silenio and I have fixed the "re-posts itself" problem.  Can
you try your code in the latest SWT?



                                                                                                                                           
                      hudsonr@xxxxxxxxxx                                                                                                   
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                      eclipse.org                     Subject: Re: [platform-swt-dev] Display.asyncExec premepts pending events            
                                                                                                                                           
                                                                                                                                           
                      07/24/02 05:57 PM                                                                                                    
                      Please respond to                                                                                                    
                      platform-swt-dev                                                                                                     
                                                                                                                                           
                                                                                                                                           




In readAndDispatch(), it seems like SWT prioritizes pending OS events above
Runnables that were posted asynchronously (based on the fact that this
method calls runDeferredEvents(), and then runAsyncMessages()). The problem
for me is that runAsyncMessages() in Display does not behave like I expect.
At the time when runAsyncMessages() is called, I would expect it to run
*only* the messages that are currently on the queue at that time.  But, if
one of those Runnables re-posts itself to the async queue, runAsyncMessages
() never returns.  This is the problem I am having.

It seems like readAndDispatch() might also work if it never dispatched more
than a single message, therefore runAsyncMessages() would only run the
first item in the queue.

Here is the AWT version of what I am trying to do.  (BTW, it works, meaning
UI events are prioritized)

public static void main(String[] args) {
        Frame frame = new Frame();
        Panel contents = new Panel();

        final JPanel panel = new JPanel();
        panel.setPreferredSize(new Dimension(30,30));
        frame.add(contents);
        frame.setSize(300,300);

        contents.add(new Button("foo"));
        contents.add(new Button("foo"));
        contents.add(panel);

        SwingUtilities.invokeLater(new Runnable() {
                public void run() {
                        if (panel.getBackground() == Color.gray)
                                panel.setBackground(Color.darkGray);
                        else
                                panel.setBackground(Color.gray);
                        panel.repaint();
                        SwingUtilities.invokeLater(this);
                }
        });
        frame.addWindowListener(new WindowAdapter() {
                public void windowClosing(WindowEvent e) {
                        System.exit(0);
                }
        });
        frame.show();
}