Custom event listener on Android app

Question

I need to set up a simple event listener to refresh a ListView once in a while. The problem is I don\'t know how could I generate an event.

I know that

Answer 1

1. Define a callback interface

           public interface NewsUpdateListener 
           {
               void onNewsUpdate();
           }
   

2. Provide a registration facility on the background thread which gets the RSS feed

       class  
       {
       ....
           ArrayList listeners = new ArrayList ();
       .... 
           public void setOnNewsUpdateListener (NewsUpdateListener listener) 
           {
               // Store the listener object
               this.listeners.add(listener);
           }
       ....
       }
   

3. Fire the callback when news is available

   ....
   for (listener : listeners) 
   {
       listener.onNewsUpdate();
   }
   ....
   

4. Register listener somewhere during initialization

   ....
       .registerListener
   (
       new OnNewsUpdateListener() {
           onNewsUpdate() {
               // process news data
               runOnUIThread(new Runnable() {
                   public void run() {
                       // refresh list view
                   }
               }
           }
   }
   ....