|
| |
| 15. 1. 16. 事件源和监听 |
|
|
|
import java.util.ArrayList;
import java.util.EventListener;
import java.util.EventObject;
abstract class TestEventSource {
public abstract void addListener(TestEventListener l);
public abstract void removeListener(TestEventListener l);
public abstract void fireEvent(java.util.EventObject o);
public void test() {
addListener(new TestEventListener("A"));
fireEvent(new java.util.EventObject(this));
}
}
class TestEventListener implements EventListener {
String id;
public TestEventListener(String id) {
this.id = id;
}
public void handleEvent(EventObject o) {
System.out.println(id + " called");
if (id.equals("C")) {
((TestEventSource) o.getSource()).removeListener(this);
}
}
}
public class Main extends TestEventSource {
ArrayList listeners = new ArrayList();
public void addListener(TestEventListener l) {
listeners.add(l);
}
public void removeListener(TestEventListener l) {
listeners.remove(l);
}
public void fireEvent(EventObject o) {
for (int i = 0; i < listeners.size(); i++) {
TestEventListener l = (TestEventListener) listeners.get(i);
l.handleEvent(o);
}
}
public static void main(String[] args) {
Main pfles = new Main();
pfles.test();
}
}
|
|
|
