parse string to datetime
dependencies:
intl: ^0.17.0
import 'package:intl/intl.dart';
DateFormat dateFormat = DateFormat("yyyy-MM-dd HH:mm:ss");
String string = dateFormat.format(DateTime.now()); //Converting DateTime object to String
DateTime dateTime = dateFormat.parse("2019-07-19 8:40:23"); //Converting String to DateTime object