当前时间显示

NSLog(@"%@",[self formateDate:@"2016-05-13 17:30" withFormate:@"YYYY-MM-dd HH:mm"]);

/**
和当前时间比较
1）1分钟以内       显示 :   刚刚
2）1小时以内       显示 :   X分钟前
3）今天或者昨天     显示 :   今天 09:30   昨天 09:30
4) 今年           显示 :   09月12日
5) 大于本年        显示 :   2013/09/09
*/

- (NSString *)formateDate:(NSString *)dateString withFormate:(NSString *) formate
{
@try {
//实例化一个NSDateFormatter对象
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:formate];

NSDate * nowDate = [NSDate date];

//  将需要转换的时间转换成 NSDate 对象
NSDate * needFormatDate = [dateFormatter dateFromString:dateString];
//  取当前时间和转换时间两个日期对象的时间间隔
//  这里的NSTimeInterval 并不是对象，是基本型，其实是double类型，是由c定义的:  typedef double NSTimeInterval;
NSTimeInterval time = [nowDate timeIntervalSinceDate:needFormatDate];

// 再然后，把间隔的秒数折算成天数和小时数：
NSString *dateStr = @"";

if (time <= 60) {  // 1分钟以内的
dateStr = @"刚刚";
}else if(time <= 60*60){  //  一个小时以内的

int mins = time/60;
dateStr = [NSString stringWithFormat:@"%d分钟前",mins];

}else if(time <= 60*60*24*2){   // 在两天内的

[dateFormatter setDateFormat:@"YYYY/MM/dd"];
NSString * need_yMd = [dateFormatter stringFromDate:needFormatDate];
NSString *now_yMd = [dateFormatter stringFromDate:nowDate];

[dateFormatter setDateFormat:@"HH:mm"];
if ([need_yMd isEqualToString:now_yMd]) {
// 在同一天
dateStr = [NSString stringWithFormat:@"今天 %@",[dateFormatter stringFromDate:needFormatDate]];
}else{
//  昨天
dateStr = [NSString stringWithFormat:@"昨天 %@",[dateFormatter stringFromDate:needFormatDate]];
}
}else {

[dateFormatter setDateFormat:@"yyyy"];
NSString * yearStr = [dateFormatter stringFromDate:needFormatDate];
NSString *nowYear = [dateFormatter stringFromDate:nowDate];

if ([yearStr isEqualToString:nowYear]) {
//  在同一年
[dateFormatter setDateFormat:@"MM月dd日"];
dateStr = [dateFormatter stringFromDate:needFormatDate];
}else{
[dateFormatter setDateFormat:@"yyyy/MM/dd"];
dateStr = [dateFormatter stringFromDate:needFormatDate];
}
}
return dateStr;
}
@catch (NSException *exception) {
return @"";
}
}

更准确的方法

[self formateDate:@"2016-05-30 21:57:46" withFormat:@"YYYY-MM-dd HH:mm:ss"];

- (void)formateDate:(NSString *)dateString withFormat:(NSString *) formate{

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:formate];
NSDate * nowDate = [NSDate date];
NSDate * needFormatDate = [dateFormatter dateFromString:dateString];

NSTimeInterval secondsPerDay = 24 * 60 * 60;
NSDate *yearsterDay =  [[NSDate alloc] initWithTimeIntervalSinceNow:-secondsPerDay];
NSTimeInterval thirdPerDay = 48 * 60 * 60;
NSDate * qian = [[NSDate alloc] initWithTimeIntervalSinceNow:-thirdPerDay];
//假设这是你要比较的date：NSDate *yourDate = ……
//日历
NSCalendar* calendar = [NSCalendar currentCalendar];
unsigned unitFlags = NSYearCalendarUnit | NSMonthCalendarUnit |  NSDayCalendarUnit;
NSDateComponents* comp1 = [calendar components:unitFlags fromDate:needFormatDate];
NSDateComponents* comp2 = [calendar components:unitFlags fromDate:yearsterDay];
NSDateComponents * comp3 = [calendar components:unitFlags fromDate:qian];

if ( comp1.year == comp2.year && comp1.month == comp2.month && comp1.day == comp2.day) {
NSLog(@"昨天");
}
if (comp1.year == comp3.year && comp1.month == comp3.month && comp1.day == comp3.day) {
NSLog(@"前天");
}
}