DateTime有用代码段

DateTime.Parse(DateTime.Now.Tostring("yyyy-MM-dd")).AddDays(-7).ToString("yyyy-MM-dd");

2.生日计算

class AgeByBirthUtils {
  static String getAge(DateTime brt){
    int age = 0;
    DateTime dateTime = DateTime.now();
    if (dateTime.isBefore(brt)) { //出生日期晚于当前时间，无法计算
      return '出生日期不正確';
    }
    int yearNow = dateTime.year;  //当前年份
    int monthNow = dateTime.month;  //当前月份
    int dayOfMonthNow = dateTime.day; //当前日期

    int yearBirth = brt.year;
    int monthBirth = brt.month;
    int dayOfMonthBirth = brt.day;
    age = yearNow - yearBirth;   //计算整岁数
    if (monthNow <= monthBirth) {
      if (monthNow == monthBirth) {
        if (dayOfMonthNow < dayOfMonthBirth) age--;//当前日期在生日之前，年龄减一
      } else {
        age--;//当前月份在生日之前，年龄减一
      }
    }
    return age.toString();
  }
}

3.flutter dart 获取当前时间戳

static int currentTimeMillis() {
    return new DateTime.now().millisecondsSinceEpoch;
  }

 var now = new DateTime.now();
    var format = new DateFormat('HH:mm a');
    var date = new DateTime.fromMillisecondsSinceEpoch(timestamp * 1000);
    var diff = now.difference(date);
    var time = '';

    if (diff.inSeconds <= 0 || diff.inSeconds > 0 && diff.inMinutes == 0 || diff.inMinutes > 0 && diff.inHours == 0 || diff.inHours > 0 && diff.inDays == 0) {
      time = format.format(date);