flutter-时间日期相关

1、获取当前时间

var now = new DateTime.now();
print ("${now.year}-${now.month}-${now.day}");
print(now);//2022-02-07 04:12:18.125116

2、设置时间

var d =new DateTime(2022, 2, 7, 18, 37 , 26);

print(d);//2022-02-07 18:37:26.000

3、创建UTC时间

var ds = new DateTime.utc(2019, 10, 10, 9, 30);

print(ds);//2019-10-10 09:30:00.000Z

4、解析时间

var d1 = DateTime.parse('2018-10-10 09:30:36');

print(d1);//2020-10-10 09:30:36.000

var d2 = DateTime.parse('2018-10-10 09:30:30+0800');

print(d2);//2020-10-10 01:30:30.000Z

5、时间加减

var now = new DateTime.now();//2022-02-07 04:17:30.905388

print(now.add(new Duration(minutes: 10)));//加10分钟  2022-02-07 04:27:37.905388

print(now.add(new Duration(minutes: -10)));//减10分钟  2022-02-07 04:07:37.905388

print(now.add(new Duration(hours: 2)));//加2小时 2022-02-07 06:17:37.905388

print(now.add(new Duration(hours: -2)));//减2小时 2022-02-07 02:17:37.905388

6、 比较时间

var d3 = new DateTime(2019, 6, 20);

var d4 = new DateTime(2019, 7, 20);

var d5 = new DateTime(2019, 6, 20);

print(d3.isAfter(d4));//是否在d4之后 false

print(d3.isBefore(d4));//是否在d4之前 true

print(d3.isAtSameMomentAs(d5));//是否相同 true

7、计算时间差

var d6 = new DateTime(2019, 6, 19, 16 , 30);

var d7 = new DateTime(2019, 6, 20, 15, 20);

var difference = d7.difference(d6);

print([difference.inDays, difference.inHours,difference.inMinutes]);//d6与d7相差的天数与小时,分钟

8、时间戳

var now = new DateTime.now();

print(now.millisecondsSinceEpoch);//单位毫秒，13位时间戳  1644178922997

print(now.microsecondsSinceEpoch);//单位微秒，16位时间戳  1644178922997751

9、打印当前时间

var now = new DateTime.now();

// padLeft(int width,String sring)：如果字符串长度小于width，在左边填充sring

String  timeStr="${now.year.toString()}-${now.month.toString().padLeft(2,'0')}-${now.day.toString().padLeft(2,'0')} ${now.hour.toString().padLeft(2, '0')}:${now.minute.toString().padLeft(2, '0')}:${now.second.toString().padLeft(2, '0')}";

print(timeStr);//2022-02-10 02:29:40

10、手机当前的时区

print('${DateTime.now().timeZoneName}');//CST

11、手机当前的时区的偏移量

print('${DateTime.now().timeZoneOffset}');//8:00:00.000000  缩写为+8.00

12、某年的某月有多少天

  int _getDaysInMonth() {
    return DateUtils.getDaysInMonth(_selectedYear, _selectedMonth);
  }

13、某年某月的第一天是星期几

final weekday = DateTime(_selectedYear, _selectedMonth).weekday;

https://www.jianshu.com/p/58a21acf156a