Custom event listener on Android app

Solution 1:

1. Define a callback interface

           public interface NewsUpdateListener 
           {
               void onNewsUpdate(<News data to be passed>);
           }
   

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

       class <Background processing class name> 
       {
       ....
           ArrayList<NewsUpdateListener> listeners = new ArrayList<NewsUpdateListener> ();
       .... 
           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(<News data to be passed>);
   }
   ....
   

4. Register listener somewhere during initialization

   ....
       <class <Background processing class object>.registerListener
   (
       new OnNewsUpdateListener() {
           onNewsUpdate(<News Data>) {
               // process news data
               runOnUIThread(new Runnable() {
                   public void run() {
                       // refresh list view
                   }
               }
           }
   }
   ....
   

Solution 2:

try this:

interface MyHandlerInterface
{
   void onHandle(Object obj)
}
class myListClass
{
   MyHandlerInterface myHandler;
   public void setHandlerListener(MyHandlerInterface listener)
   {
      myHandler=listener;
   }
   protected void myEventFired(myObj)
   {
      if(myHandler!=null)
         myHandler.onHandle(myObj);
   }
}