Re: Need help/tutoring off-list

[Chimera <ch...@ennersea.net>]

Is there anyone available/willing to help people anymore on this list?   
This list has become dangerously quiet with the absence/busy-ness of 
Thomas and a few others. :(



Chimera wrote:

> Would anyone on the list be willing to look through my code (multiple 
> files) and help me where I am having errors?  It should be a simple 
> newbie error, easy for you guys to spot.
> This is the situation.  I am building an app to learn from, and am 
> combining Ivor Horton's Beginning Java 2 (1.4 Edition) and the SVG 
> Example from the Batik website.  My end goal is an open source 
> wargame, just something I have always wanted to do, combined with the 
> learning to program goal I have.
>
> The application has multiple classes.
> OpenWarSim        main class
> AppMainFrame      the actual application frame
> MapView           class that loads an SVG file that works in the SVG 
> viewer
> StatusBar         bottom bar that gives feedback and data
> ( a few other supporting files )
>
> The OpenWarSim file is the main class that when launched, fires a 
> splashscreen class (now commented out for speed) and the 
> AppMainFrame.  AppMainFrame consists of a menu bar (two things 
> working:  Game > Load Map, Game > Exit and Close) a JPanel and a 
> Status Bar that gives feedback.
>
> Now, the StatusBar class works.  I have successfully pumped the SVG 
> listener events to give output to this bar.  However, the process 
> stops at addGVTTreeBuilderListener which is what started my problems.  
> addGVTTreeRendererListener never fires.  As a note, the Batik .jars 
> are included fine, and when I build SVGTestExample.java (the Batik 
> example from the site) in this same package as a standalone class, it 
> builds fine.  It was this that I used to troubleshoot any svg errors 
> in my file. :)
>
> I suspect that this is a simple problem with how I have constructed 
> things.  Inside the JScrollPane in the AppMainFrame center, I am 
> trying to create the JSVGCanvas.
>
> //  Begin AppMainFrame class code...
>
>        // TODO - This is where we are seemingly failing.  The MapView 
> JScrollPane is not
>        //           being created at all.        JScrollPane 
> panel        = new JScrollPane();
>              // Set up the main window data.
>        panel.setPreferredSize(new java.awt.Dimension(mapWidth, 
> mapHeight));
>              // The main map, displaying elements, routes and objectives.
>        panel.setToolTipText("Situation and Update Map");
>        JSVGCanvas svgCanvas = new JSVGCanvas();
>        panel.add(svgCanvas);
>
>        // Add the windowTabbedPane to the MasterFrame, centered.
>        getContentPane().add(panel, java.awt.BorderLayout.CENTER);
>              MapView mapView            = new MapView(mainApp, panel);
>  
>  // .... skip a lot of menu building code ...
>
>    private void 
> loadMapMenuItemActionPerformed(java.awt.event.ActionEvent evt) {
>        JFileChooser chooser = new JFileChooser(owsMapsDirectory);
>        int choice = chooser.showOpenDialog(mapView);
>        if (choice == JFileChooser.APPROVE_OPTION) {
>            File file = chooser.getSelectedFile();
>            try {
>                svgCanvas.setURI(file.toURL().toString());
>            } catch (IOException ex) {
>                ex.printStackTrace();
>            }
>        }
>    }
>
> //  End AppMainFrame class code...
>
>
> //  Begin MapView class code...
>
> public MapView(OpenWarSim mainApp, JScrollPane panel) {
>        // Default constructor
>        this.mainApp    = mainApp;
>        panel.setPreferredSize(new java.awt.Dimension(mapWidth, 
> mapHeight));
>        createMapView(panel);
>    }
>
>    public JScrollPane createMapView(JScrollPane panel) {
>        JSVGCanvas svgCanvas = new JSVGCanvas();
>        panel.add(svgCanvas);
>          // Below here, the SVG Event Listeners are set up.
>
> //  End MapView class code...
>
> Now this morning when I started futzing with it, it was working up to 
> the addGVTTreeRendererListener event not firing... but no errors.  
> Now, after messing... it errors out with the following errors:
>
> java.lang.NullPointerException
>    at AppMainFrame.loadMapMenuItemActionPerformed(AppMainFrame.java:308)
>    at AppMainFrame.access$1(AppMainFrame.java:302)
>    at AppMainFrame$2.actionPerformed(AppMainFrame.java:143)
>    at 
> javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1786)
>    at 
> javax.swing.AbstractButton$ForwardActionEvents.actionPerformed(AbstractButton.java:1839) 
>
>    at 
> javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:420) 
>
>    at 
> javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:258)
>    at javax.swing.AbstractButton.doClick(AbstractButton.java:289)
>    at 
> javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:1113)
>    at 
> javax.swing.plaf.basic.BasicMenuItemUI$MouseInputHandler.mouseReleased(BasicMenuItemUI.java:943) 
>
>    at java.awt.Component.processMouseEvent(Component.java:5100)
>    at java.awt.Component.processEvent(Component.java:4897)
>    at java.awt.Container.processEvent(Container.java:1569)
>    at java.awt.Component.dispatchEventImpl(Component.java:3615)
>    at java.awt.Container.dispatchEventImpl(Container.java:1627)
>    at java.awt.Component.dispatchEvent(Component.java:3477)
>    at 
> java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:3483)
>    at 
> java.awt.LightweightDispatcher.processMouseEvent(Container.java:3198)
>    at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3128)
>    at java.awt.Container.dispatchEventImpl(Container.java:1613)
>    at java.awt.Window.dispatchEventImpl(Window.java:1606)
>    at java.awt.Component.dispatchEvent(Component.java:3477)
>    at java.awt.EventQueue.dispatchEvent(EventQueue.java:456)
>    at 
> java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:201) 
>
>    at 
> java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151) 
>
>    at 
> java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:145)
>    at 
> java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:137)
>    at java.awt.EventDispatchThread.run(EventDispatchThread.java:100)
>
> This is dying at the try block in the loadMapView() method, 
> specifically at the setURI call.
>
> I can zip and send the entire thing so that someone could help me 
> figure out what I am doing wrong.  My guess is that for some reason, 
> the JSVGCanvas component is not properly referenced/linked into the 
> application.  I have tried setting the JScrollPane's background color, 
> as well as the JSVGCanvas, neither of which work... which makes me 
> think that this is a simple reference error on my part... but I can't 
> find it.  :(
>
> Many thanks in advance.  Just email me and I can forward the files.
>


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