title: facebook android sdk sharedialog callback is always success
body: <p>Using Facebook android sdk version <strong>4.1.1</strong>, I managed to open a shareDialog and share a content using the below code:</p>
  
  <pre><code>if (ShareDialog.canShow(ShareLinkContent.class)) {
          ShareLinkContent linkContent = new ShareLinkContent.Builder()
                  .setContentTitle("Hello Facebook")
                  .setContentDescription(
                          "The 'Hello Facebook' sample  showcases simple Facebook integration")
                  .setContentUrl(Uri.parse("http://developers.facebook.com/android"))
                  .build();
  
          shareDialog.show(linkContent);
          shareDialog.registerCallback(callbackManager, new FacebookCallback&lt;Sharer.Result&gt;() {
  
              @Override
              public void onSuccess(Result result) {
                  //always gets called
  
              }
  
              @Override
              public void onCancel() {
                  //do something
  
              }
  
              @Override
              public void onError(FacebookException error) {
                  // TODO Auto-generated method stub
  
              }
  
          });
      }
  </code></pre>
  
  <p>and the callback on ActivityResult code:</p>
  
  <pre><code>@Override
  protected void onActivityResult(final int requestCode, final int resultCode, final Intent data) {
      super.onActivityResult(requestCode, resultCode, data);
      callbackManager.onActivityResult(requestCode, resultCode, data);
  }
  </code></pre>
  
  <p>the resultCode is always -1 which is <strong>RESULT_OK</strong> regardless whether user pressed <strong>back</strong> or <strong>post</strong> button of the dialog. and the callback's onSuccess function is always called and the postId is always null regardless whether the content is posted or cancelled. Anyone know why is it acting this way?</p>