Adding Your Own Library Events

domizai

Hi! How to make my custom event handler and event class that fires an event every second by updating a integer value?

I was following this tutorial Library-Basics.

What i actually much want to accomplish is pretty much the same as in the sDrop library-basic example, to use my own kind of event handler. I don't really know how to actually fire an event as described here: Describing Your Library --> public void makeEvent(EventClass event)

Let's say EventClass is updating a value every second which i want to treat as a fake event. In the main Sketch i want to get the updated value like this:

void fancyEvent(EventClass event){  
  println(event.count); 
}

Now, how can i actually make that EventClass to fire an Event every second and updating (int)count and listen to it?

thx!

/ / / / / / / / / / / / / / / / / / / / /

So after an intensive day of research about reflection i found the solution.

import processing.core.*; // registerMethod
import java.lang.reflect.*;

EventObj obj;
Handler hand;

void setup(){
  hand = new Handler(this);
  obj = new EventObj(hand);
}

void draw(){ }


// handler method
void getSth(EventObj event){ println( event.getVal() ); }

// fire an event in the EventObj Object
void mousePressed(){ obj.process(); }


// This class handles the EventObj-Event
public class Handler {
  private Method myMethod;
  protected Object parent;
  protected PApplet parentSketch;
  
  public Handler(PApplet parent){ // Object theObject
    this.parent = parent;
    Class myClass = parent.getClass();
    parent.registerMethod("dispose", this);
        
    try {
      myMethod = myClass.getDeclaredMethod("getSth", new Class[] { EventObj.class } ); 
      myMethod.setAccessible(true);
    } catch (Exception e) { println(e); }
  }
  
  protected void invokeEvent(EventObj event){
    try {
      myMethod.invoke( parent, new Object[] { event });
      println("Handler received event from an EventObj-Object.");
     } catch (Exception e) { println(e); }
  }
  
  
  public void dispose(){  System.out.println("Handler says bye."); }
}



// This Class fires an Event and passes it to the Handler Object
public class EventObj {
  Handler handler; int val = 0;

  protected EventObj(Handler theHandler){ handler = theHandler; }  
  public int getVal(){ return this.val; }  
  // this will tell the Handler Object than an event happened.
  protected void process() { 
    val++; // the actuall event.
    println("EventObj fired an Event.");
    handler.invokeEvent(this); }
}

/*
Outputs:
EventObj fired an Event.
1
Handler received event from an EventObj-Object.
EventObj fired an Event.
2
Handler received event from an EventObj-Object.
EventObj fired an Event.
3
Handler received event from an EventObj-Object.
Handler says bye.
*/