private ActivityChooserModel(Context context,String historyFileName){
  mContext=context.getApplicationContext();
  if (!TextUtils.isEmpty(historyFileName) && !historyFileName.endsWith(HISTORY_FILE_EXTENSION)) {
    mHistoryFileName=historyFileName + HISTORY_FILE_EXTENSION;
  }
 else {
    mHistoryFileName=historyFileName;
  }
}

private ActivityChooserModel ( Context context , String historyFileName ) { mContext = context . getApplicationContext ( ) ; if ( ! TextUtils . isEmpty ( historyFileName ) && ! historyFileName . endsWith ( HISTORY_FILE_EXTENSION ) ) { mHistoryFileName = historyFileName + HISTORY_FILE_EXTENSION ; } else { mHistoryFileName = historyFileName ; } }
creates a new instance .
