Facebook SDK 3.8.0 share dialog: manage the cancellation by the user

Question

I'm developing an application that uses the Facebook share dialog. Here's my dialog implementation:

FacebookDialog shareDialog = new FacebookDialog.ShareDialogBuilder(this)
                        .setLink(playStoreLink)
                        .setName(appName)
                        .setDescription("I'm here with "+name)
                        .setPicture(linkPicture)
                        .build();
                    uiHelper.trackPendingDialogCall(shareDialog.present());

And here's the onActivityResult

@Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        uiHelper.onActivityResult(requestCode, resultCode, data, new FacebookDialog.Callback() {
            @Override
            public void onError(FacebookDialog.PendingCall pendingCall, Exception error, Bundle data) {
                Utilities.GeneralDismissableDialog(context, String.format("Error: %s", error.toString()));
            }

            @Override
            public void onComplete(FacebookDialog.PendingCall pendingCall, Bundle data) {
                Toast.makeText(context, "Success!", Toast.LENGTH_LONG).show();
            }
        });
    }

Now if the user press the back button, the onComplete method is invoked, so the application prints the success message "Success!". I read the dcomunetation but i didn't find any suggestions.

How can i manage the cancellation by the user?