java-gnome-developer

[Java-gnome-developer] using inherited methods in glade signal handlers

[Lars W. <la...@di...>]

Hi all,

is it not possible to call inherited methods in signal handlers
specified in glade?  For example, if I have a class Frame with a method
doClose() and an instance of the class Preferences that inherits from
Frame and acts as the owner of a glade-generated preferences window, is
it not possible for me to specify doClose() as the handler for a signal
in glade?

Currently, when I try to do something like the above, I get the
following:

        ListenerDelegate.fireEvent(org.gnu.gtk.event.ButtonEvent[source=org.gnu.gtk.Button@1bdc9d8,id=CLICK]): java.lang.IllegalAccessException: Class org.gnu.glade.ListenerDelegate can not access a member of class org.zentren.zinfo.ui.Frame with modifiers "public"
        java.lang.IllegalAccessException: Class
        org.gnu.glade.ListenerDelegate can not access a member of class
        org.zentren.zinfo.ui.Frame with modifiers "public"
        	at
        sun.reflect.Reflection.ensureMemberAccess(Reflection.java:65)
        	at java.lang.reflect.Method.invoke(Method.java:578)
        	at
        org.gnu.glade.ListenerDelegate.fireEvent(ListenerDelegate.java:88)
        	at
        org.gnu.glade.ListenerDelegate.fireEvent(ListenerDelegate.java:60)
        	at
        org.gnu.glade.ButtonDelegate.buttonEvent(ButtonDelegate.java:20)
        	at org.gnu.gtk.Button.fireButtonEvent(Button.java:306)
        	at org.gnu.gtk.Button.handleClick(Button.java:316)
        	at org.gnu.gtk.Gtk.gtk_main(Native Method)
        	at org.gnu.gtk.Gtk.main(Gtk.java:54)
        	at org.zentren.zinfo.ui.Viewer.main(Viewer.java:55)
        params:[Ljava.lang.Object;@1a918d5, ret:null
        
Is there a nice way around this problem or do I need to provide methods
like:

        public void doClose() {
          super.doClose();
        }
        
?

Regards,
Lars

Re: [Java-gnome-developer] using inherited methods in glade signal handlers

[Lars W. <la...@di...>]

Hello again,

since nobody answered to my previous question, let me try to ask it
again a little bit different and perhaps more clearly.

Let's say I have a class Foo:

        public class Foo {
                public void doFoo() {
                        System.out.println("Foo!");
                }
        }

Then I have another class called Bar extending Foo:

        public class Bar extends Foo {
                public Bar() {
                        try {
                                ui = new LibGlade("UI.glade", this);
                        }
                        catch(Exception e) {
                                e.printStackTrace();
                        }
                }
        }
        
Shouldn't it now be possible for me to specify the method doFoo() as a
signal handler in UI.glade (e.g. for a button click)?  Currently, when I
try to do something like this (or at least something similar), I get an
IllegalAccessException.

Regards,
Lars

Re: [Java-gnome-developer] using inherited methods in glade signal handlers

[Andrew C. <an...@op...>]

On Wed, 2006-04-01 at 14:59 +0100, Lars Weber wrote:
> Shouldn't it now be possible for me to specify the method doFoo() as a
> signal handler in UI.glade (e.g. for a button click)? 

You'd think so.

> Currently, when I
> try to do something like this (or at least something similar), I get an
> IllegalAccessException.

Huh. The only time I tried to do something like this I was overriding
abstract methods anyway so they were implemented in the Bar class
anyway.

Suggestions:

1) put
	doFoo() {
		super.doFoo();
	}
into Bar.java

2) look at the code for LibGlade(). It's pretty hairy but it could well
be doing something un-java-ish that it needs to be doing. It sounds like
it's looking for a method doFoo in Bar only, not in Bar and its
supertypes. I've not done much with reflection but I suspect that
whatever LibGlade (and it's C JNI counterpart) are doing it's not doing
it quite right.

3) Be smart about it and don't use signal auto-connection. Use
addListener() instead.

AfC
Sydney

-- 
Andrew Frederick Cowie
Operational Dynamics

Website: http://www.operationaldynamics.com/
Blog: http://research.operationaldynamics.com/blogs/andrew/
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