title: Replace callbacks with observables from RxJava
body: <p>Im using listeners as callbacks to observe asynchronous operations with Android, but I think that could be great replacing this listeners with RxJava, Im new using this library but I really like it and Im always using it with Android projects.</p>
  
  <p>Here is my code to refactor:</p>
  
  <pre><code>public void getData( final OnResponseListener listener ){
     if(data!=null &amp;&amp; !data.isEmpty()){
         listener.onSuccess();
     }
     else{
         listener.onError();
     }
  }
  </code></pre>
  
  <p>A simple callback:</p>
  
  <pre><code>public interface OnResponseListener {
     public void onSuccess();
     public void onError(); 
  }
  </code></pre>
  
  <p>And the "observer":</p>
  
  <pre><code>object.getData( new OnResponseListener() {
      @Override
      public void onSuccess() {
         Log.w(TAG," on success");
      }
  
      @Override
      public void onError() {
         Log.e(TAG," on error");
      }
  });
  </code></pre>
  
  <p>Thanks!</p>