Add Material date picker, time picker, and Cupertino date-time picker to a flutter app.

date_picker.dart

import 'dart:async';

import 'package:flutter/material.dart';
import 'package:flutter/cupertino.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  DateTime selectedDate = DateTime.now();
  TimeOfDay selectedTime = TimeOfDay.now();

  Future<Null> _selectDate(BuildContext context) async {
    final DateTime pickedDate = await showDatePicker(
        context: context,
        initialDate: selectedDate,
        firstDate: DateTime(1920, 8),
        lastDate: DateTime(2101));
    if (pickedDate != null && pickedDate != selectedDate)
      setState(() {
        selectedDate = pickedDate;
      });
  }

  Future<Null> _selectTime(BuildContext context) async {
    final TimeOfDay pickedTime = await showTimePicker(
      initialTime: TimeOfDay.now(),
      context: context,
    );
    if (pickedTime != null && pickedTime != selectedTime) {
      setState(() {
        selectedTime = pickedTime;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: <Widget>[
            Text('Selected:'),
            SizedBox(
              height: 20.0,
            ),
            Text('${selectedDate.toLocal()}'.split(' ')[0]),
            Text(selectedTime.format(context)),
            SizedBox(
              height: 20.0,
            ),
            RaisedButton(
              child: Text('Material - Select date'),
              onPressed: () => _selectDate(context),
            ),
            RaisedButton(
              child: Text('Material - Select time'),
              onPressed: () => _selectTime(context),
            ),
            RaisedButton(
              child: Text('Cupertino - Select date+time'),
              onPressed: () {
                showModalBottomSheet(
                  context: context,
                  builder: (BuildContext builder) {
                    return Container(
                      height: MediaQuery.of(context).copyWith().size.height / 3,
                      child: CupertinoDatePicker(
                        initialDateTime: DateTime.now(),
                        onDateTimeChanged: (DateTime newDate) {
                          print(newDate);
                          setState(
                            () {
                              selectedDate = newDate;
                              selectedTime = TimeOfDay.fromDateTime(newDate);
                            },
                          );
                        },
                        use24hFormat: false,
                        maximumDate: new DateTime(2022, 12, 30),
                        minimumYear: 2010,
                        maximumYear: 2022,
                        minuteInterval: 1,
                        mode: CupertinoDatePickerMode.dateAndTime,
                      ),
                    );
                  },
                );
              },
            ),
            RaisedButton(
              child: Text('Cupertino - Select just time'),
              onPressed: () {
                showModalBottomSheet(
                  context: context,
                  builder: (BuildContext builder) {
                    return Container(
                      height: MediaQuery.of(context).copyWith().size.height / 3,
                      child: CupertinoDatePicker(
                        mode: CupertinoDatePickerMode.time,
                        initialDateTime: DateTime.now(),
                        minuteInterval: 5,
                        onDateTimeChanged: (DateTime newDate) {
                          print(newDate);
                          setState(
                            () {
                              selectedDate = newDate;
                              selectedTime = TimeOfDay.fromDateTime(newDate);
                            },
                          );
                        },
                      ),
                    );
                  },
                );
              },
            ),
          ],
        ),
      ),
    );
  }
}