Help with my custom event

Question

Hi all!
I've extended JTextField to add some custom features. They can add my custom event called ValueChangedListener which listens for change in my textfields. Theese changes is registered in my JFrame holding the textfields so I can determine whether or not to save data to file on exit.
My question is this:
Can I listen to my custom events in a global way in my JFrame? Instead of adding the listener to each and every custom textfield (JFlexTextField) I would like to add ONE listener in my JFrame by calling MyJFrame.addValueChangedListener(ValueChangedEvent vce). (The method addValueChangedListener is located in my custom textfields).
Thanks in advance.

Answer 1

You need some kind of glue between the object that creates the message and the listeners. When the events are generated by your textfields, then those textfields needs at least one "address" to send the events to. Obviously, if the listener list is stored in the JFrame, your textfields will have difficulties using it.
What you can do, which might help if you want to add several listeners to all the textfields, is:
- Add only the JFrame as a listener to the textfields
- Other listeners registers themselves with the JFrame
- The JFrame keeps track of all the other listeners,
- The 'valueChanged' method in the JFrame you forward the event to all the other listeners.
You still have to call addValueChangedListener once for every textfield, though.
You can also send a reference to the JFrame to the constructor for the textfields, and do the addValueChangedListener call in that constructor.