i send image or video but when i check at parse.com in my recipientIds arrray seems like null how is that possible ?

public static final String TAG = RecipientsActivity.class.getSimpleName();

protected List<ParseUser> mFriends;
protected ParseRelation<ParseUser> mFriendsRelation;
protected ParseUser mCurrentUser;
protected MenuItem mSendMenuItem;
protected ListView recipientsListView;

protected Uri mMediaUri;
protected String mFileType;


// burasını silebilirim sora
private ListView mListView;

protected ListView getListView() {
    if (mListView == null) {
        mListView = (ListView) findViewById(android.R.id.list);
    }
    return mListView;
}

protected void setListAdapter(ListAdapter adapter) {
    getListView().setAdapter(adapter);
}

//buraya kadarını tabe


@Override
protected void onCreate(Bundle savedInstanceState) {
    //requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_recipients);



    mMediaUri = getIntent().getData();
    mFileType = getIntent().getExtras().getString(ParseConstants.KEY_FILE_TYPE);


    recipientsListView = (ListView) findViewById(R.id.recipientListView);
    recipientsListView.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);
    recipientsListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            if (recipientsListView.getCheckedItemCount() > 0){
                mSendMenuItem.setVisible(true);
            } else {
                mSendMenuItem.setVisible(false);
            }
        }
    });
}

public void onResume() {
    super.onResume();
    mCurrentUser = ParseUser.getCurrentUser();
    mFriendsRelation = mCurrentUser.getRelation(ParseConstants.KEY_FRIENDS_RELATION);

    //setProgressBarIndeterminateVisibility(true);

    ParseQuery<ParseUser> query = mFriendsRelation.getQuery();
    query.addAscendingOrder(ParseConstants.KEY_USERNAME);
    query.findInBackground(new FindCallback<ParseUser>() {
        @Override
        public void done(List<ParseUser> friends, ParseException e) {
            // setProgressBarIndeterminateVisibility(false);

            if (e == null) {
                mFriends = friends;

                String[] usernames = new String[mFriends.size()];
                int i = 0;
                for (ParseUser user : mFriends) {
                    usernames[i] = user.getUsername();
                    i++;
                }
                ArrayAdapter<String> adapter = new ArrayAdapter<String>(recipientsListView.getContext(),
                        android.R.layout.simple_list_item_checked,
                        usernames);
                recipientsListView.setAdapter(adapter);
            } else {
                Log.e(TAG, e.getMessage());
                AlertDialog.Builder builder = new AlertDialog.Builder(RecipientsActivity.this);
                builder.setMessage(e.getMessage())
                        .setTitle(R.string.error_title)
                        .setPositiveButton(android.R.string.ok, null);
                AlertDialog dialog = builder.create();
                dialog.show();
            }
        }
    });
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu_recipients, menu);
    mSendMenuItem = menu.getItem(0);
    return (super.onCreateOptionsMenu(menu));
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()){
        case android.R.id.home:

            NavUtils.navigateUpFromSameTask(this);
           return true;
        case R.id.action_send:
            ParseObject message = createMessage();
            if(message == null){
                //error
                AlertDialog.Builder builder = new AlertDialog.Builder(this);
                builder.setMessage(R.string.error_selecting_file)
                        .setTitle(R.string.error_selecting_file_title)
                        .setPositiveButton(android.R.string.ok, null);
                        AlertDialog dialog = builder.create();
                        dialog.show();
            }
            else{
                send(message);
                finish();
            }


            return true;
    }
    return super.onOptionsItemSelected(item);
}

protected ParseObject createMessage(){
    ParseObject message = new ParseObject(ParseConstants.CLASS_MESSAGES);
    message.put(ParseConstants.KEY_SENDER_ID, ParseUser.getCurrentUser().getObjectId());
    message.put(ParseConstants.KEY_SENDER_NAME, ParseUser.getCurrentUser().getUsername());
    message.put(ParseConstants.KEY_RECIPIENT_IDS, getRecipientIds());
    message.put(ParseConstants.KEY_FILE_TYPE, mFileType);

    byte[] fileBytes = FileHelper.getByteArrayFromFile(this, mMediaUri);

    if(fileBytes == null){
        return null;

    }
    else{
        if(mFileType.equals(ParseConstants.TYPE_IMAGE)){
            fileBytes = FileHelper.reduceImageForUpload(fileBytes);

        }

        String fileName = FileHelper.getFileName(this, mMediaUri, mFileType);
        ParseFile file = new ParseFile(fileName, fileBytes);
        message.put(ParseConstants.KEY_FILE,file);

        return message;
    }

}

protected ArrayList<String> getRecipientIds(){
    ArrayList<String> recipientIds = new ArrayList<String>();
    for(int i = 0; i < getListView().getCount(); i++){
        if(getListView().isItemChecked(i)){
            recipientIds.add(mFriends.get(i).getObjectId());
        }
    }
    return recipientIds;

}


protected void send(ParseObject message){
    message.saveInBackground(new SaveCallback() {
        @Override
        public void done(ParseException e) {
            if(e == null){
                // success!
                Toast.makeText(RecipientsActivity.this, R.string.success_message, Toast.LENGTH_LONG);
            }
            else{
                AlertDialog.Builder builder = new AlertDialog.Builder(RecipientsActivity.this);
                builder.setMessage(R.string.error_sending_message)
                        .setTitle(R.string.error_selecting_file_title)
                        .setPositiveButton(android.R.string.ok, null);
                AlertDialog dialog = builder.create();
                dialog.show();
            }

        }
    });
}