java中怎样自定义监听器

    // Declare the event. It must extend EventObject.

    public class MyEvent extends EventObject {

        public MyEvent(Object source) {

            super(source);

        }

    }

    

    // Declare the listener class. It must extend EventListener.

    // A class must implement this interface to get MyEvents.

    public interface MyEventListener extends EventListener {

        public void myEventOccurred(MyEvent evt);

    }

    

    // Add the event registration and notification code to a class.

    public class MyClass {

        // Create the listener list

        protected javax.swing.event.EventListenerList listenerList =

            new javax.swing.event.EventListenerList();

    

        // This methods allows classes to register for MyEvents

        public void addMyEventListener(MyEventListener listener) {

            listenerList.add(MyEventListener.class, listener);

        }

    

        // This methods allows classes to unregister for MyEvents

        public void removeMyEventListener(MyEventListener listener) {

            listenerList.remove(MyEventListener.class, listener);

        }

    

        // This private class is used to fire MyEvents

        void fireMyEvent(MyEvent evt) {

            Object[] listeners = listenerList.getListenerList();

            // Each listener occupies two elements - the first is the listener class

            // and the second is the listener instance

            for (int i=0; i<listeners.length; i+=2) {

                if (listeners[i]==MyEventListener.class) {

                    ((MyEventListener)listeners[i+1]).myEventOccurred(evt);

                }

            }

        }

    }

    MyClass c = new MyClass();

    

    // Register for MyEvents from c

    c.addMyEventListener(new MyEventListener() {

        public void myEventOccurred(MyEvent evt) {

            // MyEvent was fired

        }

    });