最近做了一个小应用程序，是读取新浪微博的。微博上面对于新发的微博，不是告诉你具体什么时候发布的，而是告诉你几秒钟之前，几分钟之前，几个小时之前之类的相对于现在的时间。可以使用下面代码来计算这个时间差。
![复制代码]()
-
(NSString
*
)timestamp
{
//
Calculate distance time string
//
time_t now;
time(
&
now);
int
distance
=
(
int
)difftime(now, createdAt);
if
(distance
<
0
) distance
=
0
;
if
(distance
<
60
) {
self.timestamp
=
[NSString stringWithFormat:
@"
%d %s
"
, distance, (distance
==
1
)
?
"
second ago
"
:
"
seconds ago
"
];
}
else
if
(distance
<
60
*
60
) {
distance
=
distance
/
60
;
self.timestamp
=
[NSString stringWithFormat:
@"
%d %s
"
, distance, (distance
==
1
)
?
"
minute ago
"
:
"
minutes ago
"
];
}
else
if
(distance
<
60
*
60
*
24
) {
distance
=
distance
/
60
/
60
;
self.timestamp
=
[NSString stringWithFormat:
@"
%d %s
"
, distance, (distance
==
1
)
?
"
hour ago
"
:
"
hours ago
"
];
}
else
if
(distance
<
60
*
60
*
24
*
7
) {
distance
=
distance
/
60
/
60
/
24
;
self.timestamp
=
[NSString stringWithFormat:
@"
%d %s
"
, distance, (distance
==
1
)
?
"
day ago
"
:
"
days ago
"
];
}
else
if
(distance
<
60
*
60
*
24
*
7
*
4
) {
distance
=
distance
/
60
/
60
/
24
/
7
;
self.timestamp
=
[NSString stringWithFormat:
@"
%d %s
"
, distance, (distance
==
1
)
?
"
week ago
"
:
"
weeks ago
"
];
}
else
{
static
NSDateFormatter
*
dateFormatter
=
nil;
if
(dateFormatter
==
nil) {
dateFormatter
=
[[NSDateFormatter alloc] init];
[dateFormatter setDateStyle:NSDateFormatterShortStyle];
[dateFormatter setTimeStyle:NSDateFormatterShortStyle];
}
NSDate
*
date
=
[NSDate dateWithTimeIntervalSince1970:createdAt];
self.timestamp
=
[dateFormatter stringFromDate:date];
}
return
timestamp;
}
![复制代码]()
