Clock TimeStamp recorder in flutter

TimeStampClock.dart

import 'dart:async';

import 'package:flutter/material.dart';

final Color darkBlue = Color.fromARGB(255, 18, 32, 47);

void main() {
  runApp(MaterialApp(
      theme: ThemeData.light().copyWith(scaffoldBackgroundColor: darkBlue),
      debugShowCheckedModeBanner: false,
      home: TimeStampClock()));
}

class TimeStampClock extends StatefulWidget {
  @override
  ClockState createState() => ClockState();
}

class ClockState extends State<TimeStampClock> {
  DateTime now;
  String strTime;
  List<String> timeStamps = [];

  @override
  void initState() {
    super.initState();
    now = DateTime.now();
    strTime = timeToString(now);

    new Timer.periodic(Duration(seconds: 1), (Timer t) {
      setState(() {
        now = DateTime.now();
        strTime = timeToString(now);
      });
    });
  }

  String timeToString(DateTime time) {
    return "${time.hour.toString().padLeft(2, '0')}:${time.minute.toString().padLeft(2, '0')}:${time.second.toString().padLeft(2, '0')}";
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: const Text('Timer App'),
        ),
        body: Row(
          mainAxisAlignment: MainAxisAlignment.spaceBetween,
          mainAxisSize: MainAxisSize.max,
          children: [
            Expanded(
                flex: 3,
                child: InkWell(
                  onTap: () {
                    timeStamps.add(strTime);
                  },
                  child: Container(
                    padding: const EdgeInsets.symmetric(horizontal: 12.0),
                    child: Text("$strTime",
                        textAlign: TextAlign.center,
                        style: TextStyle(
                          fontSize: 20,
                          fontWeight: FontWeight.bold,
                          color: Colors.white,
                        )),
                  ),
                )),
            Expanded(
                flex: 7,
                child: ListView.builder(
                    itemCount: timeStamps.length,
                    itemBuilder: (context, idx) {
                      return InkWell(
                          child: Card(
                              color: Colors.white70,
                              child: Padding(
                                  padding: EdgeInsets.symmetric(
                                      vertical: 24.0, horizontal: 16.0),
                                  child: Text(
                                      "${timeStamps[timeStamps.length - idx - 1]}",
                                      style: TextStyle(
                                        fontSize: 20,
                                        fontWeight: FontWeight.bold,
                                        color: Colors.black,
                                      )))),
                          onTap: () {
                            timeStamps.removeAt(timeStamps.length - idx - 1);
                          });
                    })),
          ],
        ));
  }
}