Android Development Detailed (vi)--------------event handling mechanism

1. Engineering Catalogue

2, Fireevent.java

Package Com.example.fireeevent;import java.util.eventobject;//Fire event class, binding event source public class FireEvent extends EventObject { Private Object Eventsource;public FireEvent (object source) {super (source);//TODO Auto-generated constructor Stubthis.eventsource = source;} Public Object Geteventsource () {return eventSource;}}

3, Listener.java

Package Com.example.fireeevent;import java.util.eventlistener;//Fire listener, monitoring fire events public Interface Listener extends EventListener {public void Listen (FireEvent e);}

4, Firelistener.java

Package Com.example.fireeevent;public class Firelistener implements Listener {public void Listen (FireEvent e) {//TODO Aut O-generated method StubSystem.out.println ("The House is on fire!!! ");}}

5, House.java

Package Com.example.fireeevent;import Java.util.arraylist;import java.util.list;//Event Source House category public class Home {private Boolean flag = false;private List listeners = new ArrayList ();p ublic boolean getflag () {return flag;} public void Setflag (Boolean flag) {This.flag = FLAG;IF (flag) {ntf ();}} public void AddListener (Listener l) {listeners.add (L);} Public List Getlisteners () {return listeners;} public void ntf () {for (int i = 0; i < listeners.size (); i++) {Listener L = (Listener) listeners.get (i); L.listen (New Fi Reevent (this));}}}

6, Test.java

Package com.example.fireeevent;//Testing class public class Test {public static void main (string[] args) {House H = new House (); H.add Listener (New Firelistener ()); H.addlistener (new Listener () {public void Listen (FireEvent e) {//TODO auto-generated Method StubSystem.out.println ("Smoke!!! ");}}); H.setflag (True);}}

Note: Build a Java project.

Event handling mechanism:

(1) Event object: Is the event when the specific "event", for the corresponding method of listener, as a parameter, generally exist in the listener method.

(2) Event Source: The entity that specifically accepts the event, for example, if you click a button, then the button is the event source.

(3) Event listener: Events Listener, when it has its corresponding event object generated, it calls the appropriate method for processing. This approach is also called method callback (callback)

Android Development Detailed (vi)--------------event handling mechanism