Problems with Observable
Hi all,
I'm having problems to add an observer to its observable object.
I have the class Foo, which extends Observable and the class ObserveFoo which implements Observer.
At the constructor of ObserveFoo, I have something like:
public ObserveFoo()
{
Foo f =new Foo();
f.addObserver(this);
}
I have a method which is supposed to notify those observers, so I do:
publicvoid updateObservers(Object event)
{
setChanged();
notifyObservers(event);
System.out.println(countObservers());
}
The problem is that this println is printing 0!
I think I'm having problems with some references here. Could anybody give me a light on this?
[1006 byte] By [
Valerianoa] at [2007-11-27 5:43:05]
Hi Valeriano,
I've been looking to your code, which doesn't seems to be logic. Because, the point of Foo, the Observable, is to notify the Observer. So creating an observable in the observer is not logic.
Let me give you a code example:
Foo.java
public class Foo extends Observable {
public void doSomething() {
this.setChanged();
System.out.println("foo observers: " + this.countObservers());
this.notifyObservers();
}
public static void main(String arg[]) {
Foo foo = new Foo();
FooObserver checkFoo = new FooObserver();
foo.addObserver(checkFoo);
foo.doSomething();
}
}
FooObserver.java
public class FooObserver implements Observer {
public void update(Observable o, Object arg) {
System.out.println(o + " updated, " + arg);
}
}
When i run this code, i'll get this output:
foo observers: 1
Foo@42e816 updated, null
Hope i've helped you.
