获得当前系统时间毫秒的最佳方法是什么?
当前回答
试试这个:
NSDate * timestamp = [NSDate dateWithTimeIntervalSince1970:[[NSDate date] timeIntervalSince1970]];
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"YYYY-MM-dd HH:mm:ss.SSS"];
NSString *newDateString = [dateFormatter stringFromDate:timestamp];
timestamp = (NSDate*)newDateString;
在本例中,dateWithTimeIntervalSince1970与格式化程序@"YYYY-MM-dd HH:mm:ss结合使用。它将返回带有年、月、日的日期和带有小时、分钟、秒和毫秒的时间。参见示例:"2015-12-02 04:43:15.008"。我使用NSString来确保格式之前已经写过。
其他回答
我需要一个NSNumber对象,包含[[NSDate date] timeIntervalSince1970]的确切结果。因为这个函数被调用了很多次,我并不真的需要创建一个NSDate对象,性能不是很好。
所以要得到原始函数给我的格式,试试这个:
#include <sys/time.h>
struct timeval tv;
gettimeofday(&tv,NULL);
double perciseTimeStamp = tv.tv_sec + tv.tv_usec * 0.000001;
这应该给你完全相同的结果[[NSDate date] timeIntervalSince1970]
It may be useful to know about CodeTimestamps, which provide a wrapper around mach-based timing functions. This gives you nanosecond-resolution timing data - 1000000x more precise than milliseconds. Yes, a million times more precise. (The prefixes are milli, micro, nano, each 1000x more precise than the last.) Even if you don't need CodeTimestamps, check out the code (it's open source) to see how they use mach to get the timing data. This would be useful when you need more precision and want a faster method call than the NSDate approach.
http://eng.pulse.me/line-by-line-speed-analysis-for-ios-apps/
CFAbsoluteTimeGetCurrent ()
Absolute time is measured in seconds relative to the absolute reference date of Jan 1 2001 00:00:00 GMT. A positive value represents a date after the reference date, a negative value represents a date before it. For example, the absolute time -32940326 is equivalent to December 16th, 1999 at 17:54:34. Repeated calls to this function do not guarantee monotonically increasing results. The system time may decrease due to synchronization with external time references or due to an explicit user change of the clock.
获取当前日期的毫秒数。
斯威夫特4 +:
func currentTimeInMilliSeconds()-> Int
{
let currentDate = Date()
let since1970 = currentDate.timeIntervalSince1970
return Int(since1970 * 1000)
}
let timeInMiliSecDate = Date()
let timeInMiliSec = Int (timeInMiliSecDate.timeIntervalSince1970 * 1000)
print(timeInMiliSec)
推荐文章
- 如何删除默认的导航栏空间在SwiftUI导航视图
- 如何在iOS中使用Swift编程segue
- Swift -整数转换为小时/分钟/秒
- Swift:声明一个空字典
- 在成功提交我的应用程序后,“太多符号文件”
- 首先添加一个UIView,甚至是导航栏
- 我如何改变UIButton标题颜色?
- 在Swift中如何调用GCD主线程上的参数方法?
- NSLayoutConstraints是可动画的吗?
- iOS -构建失败,CocoaPods无法找到头文件
- Xcode 4挂在“附加到(应用程序名称)”
- CFNetwork SSLHandshake iOS 9失败
- 如何解析unix时间戳到时间。时间
- 如何使用yyyyMMddHHmmss格式格式化当前时间?
- 请求失败:不可接受的内容类型:文本/html使用AFNetworking 2.0