iOS时间显示今天昨天

一、前言

　　今天无意间想起写这个功能，仔细考虑了一下，其实很简单，整体思路如下：

　　先获取你所要转换的时间的年月日，然后再获取今天和昨天的年月日，然后对比，进而返回不同的字符串。

二、实现步骤

　　首先，我们设置一下时间格式：

 NSDateFormatter *format = [[NSDateFormatter alloc] init];
    [format setDateFormat:@"YYYY年MM月dd日"];
   NSDateFormatter *fo = [[NSDateFormatter alloc] init];
    [fo setDateFormat:@"HH:mm"];

//获取传过来的时间的时分
    NSString *hoursandSec = [fo stringFromDate:date];
    
    //获取传过来的时间的date
    NSString *createDate = [format stringFromDate:date];

//获取今天
    NSDate *nowDate = [NSDate date];
    NSString *today = [format stringFromDate:nowDate];
    
    //获取昨天
    NSDate *yesterdayDate = [NSDate dateWithTimeIntervalSinceNow:-(24*60*60)];
    NSString *yesterday = [format stringFromDate:yesterdayDate];

if ([createDate isEqualToString:today]) {
        return [NSString stringWithFormat:@"今天%@",hoursandSec];
    }else if ([createDate isEqualToString:yesterday])
    {
         return [NSString stringWithFormat:@"昨天%@",hoursandSec];
    }else
    {
        return [NSString stringWithFormat:@"%@ %@",createDate,hoursandSec];
    }

　　完成。

三、附加方法源码

/获取时间：今天昨天
+(NSString *)getYMD:(NSDate *)date
{
    NSDateFormatter *format = [[NSDateFormatter alloc] init];
    [format setDateFormat:@"YYYY年MM月dd日"];
    
    //获取传过来的时间的时分
    NSDateFormatter *fo = [[NSDateFormatter alloc] init];
    [fo setDateFormat:@"HH:mm"];
    NSString *hoursandSec = [fo stringFromDate:date];
    
    //获取传过来的时间的date
    NSString *createDate = [format stringFromDate:date];
    
    //获取今天
    NSDate *nowDate = [NSDate date];
    NSString *today = [format stringFromDate:nowDate];
    
    //获取昨天
    NSDate *yesterdayDate = [NSDate dateWithTimeIntervalSinceNow:-(24*60*60)];
    NSString *yesterday = [format stringFromDate:yesterdayDate];
    
    if ([createDate isEqualToString:today]) {
        return [NSString stringWithFormat:@"今天%@",hoursandSec];
    }else if ([createDate isEqualToString:yesterday])
    {
         return [NSString stringWithFormat:@"昨天%@",hoursandSec];
    }else
    {
        return [NSString stringWithFormat:@"%@ %@",createDate,hoursandSec];
    }
}