iOS时间字符串格式化输出技巧详解

一.前言

最近项目开发过程中用到了大量的关于时间的处理,将后台返回的时间字符串转换为指定的格式时间再显示在UI上.

例如: 将后台返回的时间字符串2017-04-16 13:08:06转换为:2017年04月16日、2017年04月、04月16日、2017-04-16、2017-04、04-16、13:08、星期几等等.

项目是多人开发,由于前期没有统一处理时间转换的问题,后期发现项目中好多关于时间转换的代码,大部分都是通过(- : 等字符)截取成字符串数组再取相应时间拼接成指定格式,输出在UI显示的地方,代码非常的臃肿,并且这种方式非常不可取.

原因:后台返回的时间字符串 并不都是 2017-04-16 13:08:06这种格式,还有2017-04-16这种格式,截取前需要长度格式等校验,多了很多校验代码.非常不可取.

既然是时间,我们便要通过时间的思维来完成转换问题,不要通过截取字符串的方式

于是我便写了一个类,来统一处理转换问题.

二.效果

具体怎么操作:

三.将时间字符串->NSDate

首先我们要将2017-04-16 13:08:06或2017-04-16这种格式时间字符串转换为NSDate

我们新建一个NSDate的Category,笔者取名为NSDate+XHCategory,写一个时间字符串->NSDate方法,代码如下:

+(NSDate*)xh_dateWithFormat_yyyy_MM_dd_HH_mm_ss_string:(NSString *)string
{
  NSDateFormatter* dateFormat = [[NSDateFormatter alloc] init];
  [dateFormat setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
  NSDate *date =[dateFormat dateFromString:string];
  return date;
}

为了兼用其他格式时间字符串,我们把可能的情况都写上,如下

+(NSDate *)xh_dateWithFormat_yyyy_MM_dd_HH_mm_string:(NSString *)string
{
  NSDateFormatter* dateFormat = [[NSDateFormatter alloc] init];
  [dateFormat setDateFormat:@"yyyy-MM-dd HH:mm"];
  NSDate *date =[dateFormat dateFromString:string];
  return date;
}

+(NSDate *)xh_dateWithFormat_yyyy_MM_dd_HH_string:(NSString *)string
{
  NSDateFormatter* dateFormat = [[NSDateFormatter alloc] init];
  [dateFormat setDateFormat:@"yyyy-MM-dd HH"];
  NSDate *date =[dateFormat dateFromString:string];
  return date;
}

+(NSDate *)xh_dateWithFormat_yyyy_MM_dd_string:(NSString *)string
{
  NSDateFormatter* dateFormat = [[NSDateFormatter alloc] init];
  [dateFormat setDateFormat:@"yyyy-MM-dd"];
  NSDate *date =[dateFormat dateFromString:string];
  return date;
}

+(NSDate *)xh_dateWithFormat_yyyy_MM_string:(NSString *)string
{
  NSDateFormatter* dateFormat = [[NSDateFormatter alloc] init];
  [dateFormat setDateFormat:@"yyyy-MM"];
  NSDate *date =[dateFormat dateFromString:string];
  return date;
}

再写一个统一转换时间字符串为 NSDate的方法,如下:

+(NSDate *)xh_dateWithDateString:(NSString *)dateString
{
  NSDate *date = nil;
  date = [self xh_dateWithFormat_yyyy_MM_dd_HH_mm_ss_string:dateString];
  if(date) return date;
  date = [self xh_dateWithFormat_yyyy_MM_dd_HH_mm_string:dateString];
  if(date) return date;
  date = [self xh_dateWithFormat_yyyy_MM_dd_HH_string:dateString];
  if(date) return date;
  date = [self xh_dateWithFormat_yyyy_MM_dd_string:dateString];
  if(date) return date;
  date = [self xh_dateWithFormat_yyyy_MM_string:dateString];
  if(date) return date;
  return nil;
}

四.将NSDate -> NSDateFormatter

为什么要再转换为NSDateFormatter,有些人可能已经明白了,我们点开NSDateFormatter可以看到NSDateFormatter有以下属性

@property (nullable, copy) NSCalendar *calendar NS_AVAILABLE(10_7, 4_0);
@property (nullable, copy) NSTimeZone *timeZone NS_AVAILABLE(10_7, 4_0);
@property NSInteger era;
@property NSInteger year;
@property NSInteger month;
@property NSInteger day;
@property NSInteger hour;
@property NSInteger minute;
@property NSInteger second;
@property NSInteger nanosecond NS_AVAILABLE(10_7, 5_0);
@property NSInteger weekday;
@property NSInteger weekdayOrdinal;
@property NSInteger quarter NS_AVAILABLE(10_6, 4_0);
@property NSInteger weekOfMonth NS_AVAILABLE(10_7, 5_0);
@property NSInteger weekOfYear NS_AVAILABLE(10_7, 5_0);
@property NSInteger yearForWeekOfYear NS_AVAILABLE(10_7, 5_0);
@property (getter=isLeapMonth) BOOL leapMonth NS_AVAILABLE(10_8, 6_0);
@property (nullable, readonly, copy) NSDate *date NS_AVAILABLE(10_7, 4_0);

@end

我们新建一个NSDateComponents 的Category,笔者取名NSDateComponents+XHCategory,并实现如下方法:

+(NSDateComponents *)xh_dateComponentsFromDate:(NSDate *)date
{
  NSDateComponents *components = [[NSCalendar currentCalendar] components:NSCalendarUnitYear| NSCalendarUnitMonth | NSCalendarUnitDay | NSCalendarUnitWeekOfYear | NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond | NSCalendarUnitWeekday | NSCalendarUnitWeekdayOrdinal fromDate:date];
  return components;

}

接着我们就可以进行转换操作了,我们新建一个NSString的Category,笔者取名NSString+XHDateFormat

在NSString+XHDateFormat.h文件中写上需要转换的类型如下:

/**
 * x年x月x日
 */
@property(nonatomic,copy,readonly)NSString *xh_formatNianYueRi;

/**
 * x年x月
 */
@property(nonatomic,copy,readonly)NSString *xh_formatNianYue;

/**
 * x月x日
 */
@property(nonatomic,copy,readonly)NSString *xh_formatYueRi;

/**
 * x年
 */
@property(nonatomic,copy,readonly)NSString *xh_formatNian;

/**
 * x时x分x秒
 */
@property(nonatomic,copy,readonly)NSString *xh_formatShiFenMiao;

/**
 * x时x分
 */
@property(nonatomic,copy,readonly)NSString *xh_formatShiFen;

/**
 * x分x秒
 */
@property(nonatomic,copy,readonly)NSString *xh_formatFenMiao;

/**
 * yyyy-MM-dd
 */
@property(nonatomic,copy,readonly)NSString *xh_format_yyyy_MM_dd;

/**
 * yyyy-MM
 */
@property(nonatomic,copy,readonly)NSString *xh_format_yyyy_MM;

/**
 * MM-dd
 */
@property(nonatomic,copy,readonly)NSString *xh_format_MM_dd;

/**
 * yyyy
 */
@property(nonatomic,copy,readonly)NSString *xh_format_yyyy;

/**
 * HH:mm:ss
 */
@property(nonatomic,copy,readonly)NSString *xh_format_HH_mm_ss;

/**
 * HH:mm
 */
@property(nonatomic,copy,readonly)NSString *xh_format_HH_mm;

/**
 * mm:ss
 */
@property(nonatomic,copy,readonly)NSString *xh_format_mm_ss;

#pragma mark - 转换为星期几
@property(nonatomic,copy,readonly)NSString *xh_formatWeekDay;

在 NSString+XHDateFormat.m 实现如下:

-(NSString *)xh_formatNianYueRi
{
  NSDate *date = [NSDate xh_dateWithDateString:self];
  return [NSString stringWithFormat:@"%ld年%02ld月%02ld日",date.year,date.month,date.day];
}
-(NSString *)xh_formatNianYue
{
  NSDate *date = [NSDate xh_dateWithDateString:self];
  return [NSString stringWithFormat:@"%ld年%02ld月",date.year,date.month];
}
-(NSString *)xh_formatYueRi
{
  NSDate *date = [NSDate xh_dateWithDateString:self];
  return [NSString stringWithFormat:@"%02ld月%02ld月",date.month,date.day];
}
-(NSString *)xh_formatNian
{
  NSDate *date = [NSDate xh_dateWithDateString:self];
  return [NSString stringWithFormat:@"%ld年",date.year];
}
-(NSString *)xh_formatShiFenMiao
{
  NSDate *date = [NSDate xh_dateWithDateString:self];
  return [NSString stringWithFormat:@"%ld时%02ld分%02ld秒",date.hour,date.minute,date.seconds];
}
-(NSString *)xh_formatShiFen
{
  NSDate *date = [NSDate xh_dateWithDateString:self];
  return [NSString stringWithFormat:@"%ld时%02ld分",date.hour,date.minute];
}
-(NSString *)xh_formatFenMiao
{
  NSDate *date = [NSDate xh_dateWithDateString:self];
  return [NSString stringWithFormat:@"%02ld分%02ld秒",date.minute,date.seconds];
}
-(NSString *)xh_format_yyyy_MM_dd
{
  NSDate *date = [NSDate xh_dateWithDateString:self];
  return [NSString stringWithFormat:@"%ld-%02ld-%02ld",date.year,date.month,date.day];
}
-(NSString *)xh_format_yyyy_MM
{
  NSDate *date = [NSDate xh_dateWithDateString:self];
  return [NSString stringWithFormat:@"%ld-%02ld",date.year,date.month];
}
-(NSString *)xh_format_MM_dd
{
  NSDate *date = [NSDate xh_dateWithDateString:self];
  return [NSString stringWithFormat:@"%02ld-%02ld",date.month,date.day];
}
-(NSString *)xh_format_yyyy
{
  NSDate *date = [NSDate xh_dateWithDateString:self];
  return [NSString stringWithFormat:@"%ld",date.year];
}
-(NSString *)xh_format_HH_mm_ss
{
  NSDate *date = [NSDate xh_dateWithDateString:self];
  return [NSString stringWithFormat:@"%02ld:%02ld:%02ld",date.hour,date.minute,date.seconds];
}
-(NSString *)xh_format_HH_mm
{
  NSDate *date = [NSDate xh_dateWithDateString:self];
  return [NSString stringWithFormat:@"%02ld:%02ld",date.hour,date.minute];
}
-(NSString *)xh_format_mm_ss
{
  NSDate *date = [NSDate xh_dateWithDateString:self];
  return [NSString stringWithFormat:@"%02ld:%02ld",date.minute,date.seconds];
}

-(NSString *)xh_formatWeekDay
{
  NSString *weekStr=nil;
  NSDate *date = [NSDate xh_dateWithDateString:self];
  switch (date.weekday) {
    case 2:
      weekStr = @"星期一";
      break;
    case 3:
      weekStr = @"星期二";
      break;
    case 4:
      weekStr = @"星期三";
      break;
    case 5:
      weekStr = @"星期四";
      break;
    case 6:
      weekStr = @"星期五";
      break;
    case 7:
      weekStr = @"星期六";
      break;
    case 1:
      weekStr = @"星期天";
      break;
    default:
      break;
  }
  return weekStr;
}

五.调用:

  self.timeString = @"2017-04-16 13:08:06";

  //星期
  NSString *time0 = self.timeString.xh_formatWeekDay;

  //2017年04月16日
  NSString *time1 = self.timeString.xh_formatNianYueRi;

  //2017年04月
  NSString *time2 = self.timeString.xh_formatNianYue;

  //04月16日
  NSString *time3 = self.timeString.xh_formatYueRi;

  //2017年
  NSString *time4 = self.timeString.xh_formatNian;

  //13时08分01秒
  NSString *time5 = self.timeString.xh_formatShiFenMiao;

  //13时08分
  NSString *time6 = self.timeString.xh_formatShiFen;

  //08分01秒
  NSString *time7 = self.timeString.xh_formatFenMiao;

  //2017-04-16
  NSString *time8 = self.timeString.xh_format_yyyy_MM_dd;

  //2017-04
  NSString *time9 = self.timeString.xh_format_yyyy_MM;

  //04-16
  NSString *time10 = self.timeString.xh_format_MM_dd;

  //2017
  NSString *time11 = self.timeString.xh_format_yyyy;

  //13:08:06
  NSString *time12 = self.timeString.xh_format_HH_mm_ss;

  //13:08
  NSString *time13 = self.timeString.xh_format_HH_mm;

  //08:06
  NSString *time14 = self.timeString.xh_format_mm_ss;

github地址：https://github.com/CoderZhuXH/XHDate

完整项目下载地址：XHDate_jb51.rar

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