如何在J2ME / Blackberry中引发自定义事件？

Question

Just started doing some code porting from .Net CF to Blackberry JDE 4.6.1. But haven't found how to implement custom events.

I have a custom syncManager that raise events in .Net CF so I can update the UI (sort of the observer patron).

Any pointers or help where I can start?

Answer 1

I can recommend the j2me-observer project. It has a liberal license and will give you an implementation of the observer pattern which isn't included in J2ME. It can be used to allow UI changes to happen based on fired events.

Answer 2

you can send custom event using.

//you can use any int value for CUSTOM_EVENT
    fieldChangeNotify(CUSTOM_EVENT);

and you can handle that event using

public void fieldChanged(Field field, int context) {  
   if(cotext == CUSTOM_EVENT){
   Dialog.alert("custom event");  
   }

}  

Answer 3

I can recommend the open source project javaEventing. It's available at http://code.google.com/p/javaeventing , and makes it easy to define, register for and trigger custom events, much like in C#. An example:

Class MyEvent extends EventManager.EventObject {}

EventManager.registerEventListener(new EventManager.GenericEventListener(){
public void eventTriggered(Object sender, Event event) { // <-- The event is triggered, do something.
} }, new MyEvent()); EventManager.triggerEvent(this, new MyEvent()); // <-- Trigger the event

bob