时间戳:时间戳是指格林威治时间1970年01月01日00时00分00秒(北京时间1970年01月01日08时00分00秒)起至现在的总秒数

本文对时间戳的处理主要仿照微信聊天对时间的显示,根据时间戳判断出今天,昨天,前天,以及以往的时间.

1. iOS 获取当前时间戳的方法:

NSTimeInterval  timeNow=[[NSDate date] timeIntervalSince1970];

2.由时间戳转换到标准时间格式的工具类

#import <UIKit/UIKit.h>

@interface TimeStampToString : NSObject

///由时间戳转为时间格式
+(NSString *)timeStampToString:(CGFloat)timeStamp;

@end

#import "TimeStampToString.h"

@implementation TimeStampToString


+(NSString *)timeStampToString:(CGFloat)timeStamp {

    NSString *timeString = [[NSString alloc]init];
    
    //当前时间的时间戳
    NSTimeInterval  timeNow=[[NSDate date] timeIntervalSince1970];
    
    //将传来的时间戳转为标准时间格式
    NSTimeInterval time = timeStamp;
    NSDate *date = [NSDate dateWithTimeIntervalSince1970:time];
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc]init];
    [dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
    NSString *tempStr= [dateFormatter stringFromDate:date];

    timeString = [NSString stringWithFormat:@"%@年%@月%@日 %@",[tempStr substringWithRange:NSMakeRange(0,4)],[tempStr substringWithRange:NSMakeRange(5,2)],[tempStr substringWithRange:NSMakeRange(8,2)],[tempStr substringWithRange:NSMakeRange(11,8)]];

    //当前时间
    NSDate *nowDate = [NSDate date];
    NSString *nowDateStr= [dateFormatter stringFromDate:nowDate];
    
    //时间戳判断逻辑
    if ([[timeString substringWithRange:NSMakeRange(0, 4)] isEqualToString:[nowDateStr substringWithRange:NSMakeRange(0, 4)]]) {
        
        if ([[timeString substringWithRange:NSMakeRange(5,2)] isEqualToString:[nowDateStr substringWithRange:NSMakeRange(5,2)]]) {
            
            float daySubtract = [[nowDateStr substringWithRange:NSMakeRange(8,2)] floatValue] - [[timeString substringWithRange:NSMakeRange(8,2)] floatValue];
            
            if (daySubtract < 3) {
                
                if (daySubtract == 0) {
                    
                    NSString *string = [NSString stringWithFormat:@"今天 %@",[timeString substringWithRange:NSMakeRange(11,6)]];
                    return  string;
                    
                }else if (daySubtract == 1) {
                
                    NSString *string = [NSString stringWithFormat:@"昨天 %@",[timeString substringWithRange:NSMakeRange(11,6)]];
                    return  string;
                }else {
                
                    if ((timeNow - time) > 3600*24*2) {
                        
                        return timeString;
                    }else {
                    
                        NSString *string = [NSString stringWithFormat:@"前天 %@",[timeString substringWithRange:NSMakeRange(11,6)]];
                        return  string;
                    }

                }
                           
            }else{
            
               return timeString; 
            }
            
        }else {
        return timeString;
            
        }
        
    }else {
    
        return timeString;
    }
   
}
@end