Use String split method to remove :00.000
var formatedTime = currentTime.toString().split(':')
Text(formatedTime[0])
======= OR USE BELOW code for YYYY-MM-DD HH:MM:SS format without using library ====
var stringList = DateTime.now().toIso8601String().split(new RegExp(r"[T\.]"));
var formatedDate = "${stringList[0]} ${stringList[1]}";