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rakesh kumar
rakesh kumar

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Validation and Logic on datetime in Flutter

How to Compare Two DateTime in Dart/Flutter
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Question

How to Compare Two DateTime in Dart/Flutter
How to add and subtract days from current date
Flutter get Weekend and Month
How to Get Current Date and Time on Default Format:
How to Get Year/Month/Day and Hour/Minute/Second/
How to Get Date in Formatted String
How to get Time on Formatted String
How to get Time on 12-Hour Formatted String with AM and PM:
Get Last Month Date In Flutter / Dart
How get the name of the days of the week in Dart

How to Compare Two DateTime in Dart/Flutter

How to Compare Two DateTime in Dart/Flutter

How to Compare Two DateTime in Dart/Flutter 

DateTime.compareTo(DateTime other):
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DateTime dt1 = DateTime.parse("2021-12-23 11:47:00");
DateTime dt2 = DateTime.parse("2018-02-27 10:09:00");

if(dt1.compareTo(dt2) == 0){
    print("Both date time are at same moment.");
}

if(dt1.compareTo(dt2) < 0){
    print("DT1 is before DT2");
}

if(dt1.compareTo(dt2) > 0){
    print("DT1 is after DT2");
}
 DateTime.isAtSameMomentAs(DateTime other):
DateTime dt1 = DateTime.parse("2021-12-23 11:47:00");
DateTime dt2 = DateTime.parse("2018-02-27 10:09:00");

if(dt1.isAtSameMomentAs(dt2)){
   print("Both DateTime are at same moment.");
}
 DateTime.isBefore(DateTime other):
DateTime dt1 = DateTime.parse("2021-12-23 11:47:00");
DateTime dt2 = DateTime.parse("2018-02-27 10:09:00");

if(dt1.isBefore(dt2)){
   print("DT1 is before DT2");
}
 DateTime.isAfter(DateTime other):
DateTime dt1 = DateTime.parse("2021-12-23 11:47:00");
DateTime dt2 = DateTime.parse("2018-02-27 10:09:00");

if(dt1.isAfter(dt2)){
   print("DT1 is after DT2");
}
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** Flutter/Dart Full Example**:

import 'package:flutter/material.dart';

void main() {
  runApp( MaterialApp(
       home: Home()
  ));
}

class Home extends  StatefulWidget {
  @override
  State<Home> createState() => _HomeState();
}

class _HomeState extends State<Home> {

  @override
  Widget build(BuildContext context) {

    DateTime dt1 = DateTime.parse("2021-12-23 11:47:00");
    DateTime dt2 = DateTime.parse("2018-02-27 10:09:00");

    return Scaffold(
         appBar: AppBar(
            title: Text("Compare Date Time in FLutter"),
            backgroundColor: Colors.redAccent,
         ),
          body: Container(
             alignment: Alignment.center,
             padding: EdgeInsets.all(20),
             child: Column(
               children:[

                      Text("DT 1:" + dt1.toString()),
                      Text("DT 2" + dt2.toString()),

                      Text(dt1.isAfter(dt2)?"DT1 is after DT2":"DT1 is not after DT2"),
                      Text(dt1.isBefore(dt2)?"DT1 is before DT2":"DT1 is not before DT2"),

                ]
             ),
          )
      );
  }
}
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Output Screenshot:
Image description

How to Comparing only dates of DateTimes in Dart or Flutter Programming| Dart by Example

How to Compare only dates of DateTimes in Dart?
Create three Date time objects,

  1. First object date1 is using now() - 2022-04-10 20:48:56.354
  2. Second object date2 created by adding duration of 10 seconds - 2022-04-10 20:49:06.354
  3. Third object date3 created by adding duration of 10 days - 2022-04-20 20:48:56.354
  4. date1 and date2 are equal, and date1,and date3 or date2 and date3 are not equal

There are multiple ways we can check only the Dates of a DateTime object.

void main() {
  DateTime date1 = DateTime.now();
  print(date1); //2022-04-10 20:48:56.354


  var date2 = date1.add(Duration(seconds: 10));
  print(date2); //2022-04-10 20:49:06.354

  var date3 = date1.add(Duration(days: 10));
  print(date3); //2022-04-20 20:48:56.354


  print(date1.isDateEqual(date2)); // true
  print(date1.isDateEqual(date3)); // false

  print(date1.isDateEqual(date3)); // false
}

extension CompareDates on DateTime {
  bool isDateEqual(DateTime date2) {
    return year == date2.year && month == date2.month && day == date2.day;
  }
}
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Output

2022-04-10 20:48:56.354
2022-04-10 20:49:06.354
2022-04-20 20:48:56.354
true
false
false
use the difference and inDays method
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Duration difference(DateTime other)

It returns the Duration object, calls inDays that returns a number of days, checks days are zero or not.

Here is an example program.

void main() {
  DateTime date1 = DateTime.now();
  print(date1); //2022-04-10 20:48:56.354

  var date2 = date1.add(Duration(seconds: 10));
  print(date2); //2022-04-10 20:49:06.354

  var date3 = date1.add(Duration(days: 10));
  print(date3); //2022-04-20 20:48:56.354

  print(date1.difference(date2).inDays == 0); // true
  print(date1.difference(date3).inDays == 0); // false

  print(date2.difference(date3).inDays == 0); // false
}
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Output

2022-04-10 20:48:56.354
2022-04-10 20:49:06.354
2022-04-20 20:48:56.354
true
false
false
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How to Get Current Date and Time on Flutter

In this example, we are going to show you the easiest way to get the current date and time on the Flutter app with the dart. We will also show you to get date and time with different kinds of formats as well. See below for more details.

How to Get Current Date and Time on Default Format: 

String datetime = DateTime.now().toString();
print(datetime);
// 2021-08-27 19:14:57.142575
 How to Get Year/Month/Day and Hour/Minute/Second/
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var dt = DateTime.now();
print(dt.year); 
// -> Year | Output: 2021

print(dt.month); 
// -> Month | Output: 8

print(dt.day); 
// -> Day | Output: 27

print(dt.hour); 
// -> Hour | Output: 19

print(dt.minute); 
// -> Minute | Output: 19

print(dt.second); 
// -> Second | Output: 2
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How to Get Date in Formatted String

To get date and time on a formatted string, first, you need to add intl flutter package on your project dependency by adding the following lines on pubspec.yaml file.

dependencies:
  flutter:
    sdk: flutter
  intl: ^0.17.0
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import 'package:intl/intl.dart';
Now to get date on a formatted string, follow the steps below:

String cdate = DateFormat("yyyy-MM-dd").format(DateTime.now());
print(cdate);
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output: 2021-08-27
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String cdate1 = DateFormat("EEEEE, dd, yyyy").format(DateTime.now());
print(cdate1);
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 output: Friday, 27, 2021
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String cdate2 = DateFormat("MMMM, dd, yyyy").format(DateTime.now());
print(cdate2);
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output:  August, 27, 2021
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String cdate3 = DateFormat("MMM, EEE, yyyy").format(DateTime.now());
print(cdate3);
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 output:  Aug, Fri, 2021
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How to get Time on Formatted String 

String tdata = DateFormat("HH:mm:ss").format(DateTime.now());
print(tdata);
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 output: 19:36:01
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How to get Time on 12-Hour Formatted String with AM and PM 

String tdata = DateFormat("hh:mm:ss a").format(DateTime.now());
print(tdata);
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 output: 07:38:57 PM
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Get Last Month Date In Flutter / Dart

ou can just use

var prevMonth = new DateTime(date.year, date.month - 1, date.day);
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with

var date = new DateTime(2018, 1, 13);
you get

2017-12-13
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How get the name of the days of the week in Dart

Use 'EEEE' as a date pattern

 DateFormat('EEEE').format(date);
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  Thursday
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