IOS 判断日期是今天，昨天还是明天

git地址: https://github.com/JsoonLi/NSDate-Extension
 
– (NSString *)compareDate:(NSDate *)date{

    NSTimeInterval secondsPerDay = 24 * 60 * 60;
    NSDate *today = [[NSDate alloc] init];
    NSDate *tomorrow, *yesterday;

    tomorrow = [today dateByAddingTimeInterval: secondsPerDay];
    yesterday = [today dateByAddingTimeInterval: -secondsPerDay];

// 10 first characters of description is the calendar date:
    NSString * todayString = [[today description] substringToIndex:10];
    NSString * yesterdayString = [[yesterday description] substringToIndex:10];
    NSString * tomorrowString = [[tomorrow description] substringToIndex:10];

    NSString * dateString = [[date description] substringToIndex:10];

    if ([dateString isEqualToString:todayString])
    {
        return @”今天“;
    } else if ([dateString isEqualToString:yesterdayString])
    {
        return @”昨天“;
    }else if ([dateString isEqualToString:tomorrowString])
    {
        return @”明天“;
    }
    else
    {
        return dateString;
    }
}

//———————————————-
 
/**
/////  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){   //// 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 @””;
    }
}