title: Implement interface of fragment in multiple activities
body: <p>Ok so i have an activity A that has a fragment A, and an Activity B that has a fragment B. Activity A is the main screen(like a login screen). Now in fragment B, i try to do some work and when there is a session expired, i send a message, logout and go back to the main screen A. </p>
  
  <p>Now fragment B has an interface which it uses to communicate with the Activity B for other different functions. Should My Activity A implement this same interface of fragment B just for this logout session or is there a better way?</p>
  
  <p>An illustration:</p>
  
  <pre><code>public class fragmentB extends Fragment {
  
  
      public interface FragmentBProgressListener {
          public void onShowDataDialog();
          public void onRemoveData();
          public void onSessionError(String errordata);
      }
  
  
     //or should i have another interface that implements this only in activity A 
  
  }
  </code></pre>
  
  <p>Activity B:</p>
  
  <pre><code>public class ActivityB extends Activity implements FragmentBProgressListener {
  
  
      public void onShowDataDialog(){
  
        }
  
  
       public void onRemoveData(){
  
      }
  
  
      public void onSessionError(String errordata){
            // finish Activity here
     }
  
  
  }
  </code></pre>
  
  <p>Activity A:</p>
  
  <pre><code>public class ActivityA extends Activity implements FragmentAListener, FragmentBFragmentBProgressListener {
  
  
       public void onFragA(){
  
     }
  
  
       public void onShowDataDialog(){
  
        }
  
  
       public void onRemoveData(){
  
      }
  
  
      public void onSessionError(String errordata){
            // show error dialog here from fragment B
     }
  }
  </code></pre>
  
  <p>is this a good way? any pitfalls i should be aware of?</p>